Cleveland Clinic Journal of Medicine

On examination, her lung fields were clear, with no audible murmurs, and she had no lower-extremity edema. Her oxygen saturation was 98% on room air.

BREAST CALCIFICATIONS CAN MIMIC PULMONARY NODULES

Diffuse bilateral calcifications on mammography are typically benign and represent either dermal calcification (spherical lucent- centered calcification that develops from a degenerative metaplastic process) or fibrocystic changes.¹ Up to 10% of women have fibroadenomas, and 19% of fibroadenomas have microcalcifications.^2–4 Therefore, given the high prevalence, calcified breast masses should be considered in the differential diagnosis when evaluating initial chest radiographs in women.

Calcifications in the breast can overlie the lung fields and mimic pulmonary nodules. When assessing pulmonary nodules, prior imaging of the chest should always be assessed if available to determine if a lesion is new or has remained stable.

Given our patient’s age and 35-pack-year history of smoking, apparent pulmonary lesions caused concern and prompted chest CT to clarify the diagnosis. However, if the patient has no risk factors for lung malignancy, it can be safe to proceed with mammography.

By including breast calcifications in the differential diagnosis of apparent pulmonary nodules on chest radiography, the clinician can approach the case differently and inquire about a history of fibroadenomas and prior mammograms before pursuing a further workup. This can avoid unnecessary radiation exposure, the costs of CT, and apprehension in the patient raised by unwarranted concern for malignancy.

On examination, her lung fields were clear, with no audible murmurs, and she had no lower-extremity edema. Her oxygen saturation was 98% on room air.

BREAST CALCIFICATIONS CAN MIMIC PULMONARY NODULES

Diffuse bilateral calcifications on mammography are typically benign and represent either dermal calcification (spherical lucent- centered calcification that develops from a degenerative metaplastic process) or fibrocystic changes.¹ Up to 10% of women have fibroadenomas, and 19% of fibroadenomas have microcalcifications.^2–4 Therefore, given the high prevalence, calcified breast masses should be considered in the differential diagnosis when evaluating initial chest radiographs in women.

Calcifications in the breast can overlie the lung fields and mimic pulmonary nodules. When assessing pulmonary nodules, prior imaging of the chest should always be assessed if available to determine if a lesion is new or has remained stable.

Given our patient’s age and 35-pack-year history of smoking, apparent pulmonary lesions caused concern and prompted chest CT to clarify the diagnosis. However, if the patient has no risk factors for lung malignancy, it can be safe to proceed with mammography.

By including breast calcifications in the differential diagnosis of apparent pulmonary nodules on chest radiography, the clinician can approach the case differently and inquire about a history of fibroadenomas and prior mammograms before pursuing a further workup. This can avoid unnecessary radiation exposure, the costs of CT, and apprehension in the patient raised by unwarranted concern for malignancy.

On examination, her lung fields were clear, with no audible murmurs, and she had no lower-extremity edema. Her oxygen saturation was 98% on room air.

BREAST CALCIFICATIONS CAN MIMIC PULMONARY NODULES

Diffuse bilateral calcifications on mammography are typically benign and represent either dermal calcification (spherical lucent- centered calcification that develops from a degenerative metaplastic process) or fibrocystic changes.¹ Up to 10% of women have fibroadenomas, and 19% of fibroadenomas have microcalcifications.^2–4 Therefore, given the high prevalence, calcified breast masses should be considered in the differential diagnosis when evaluating initial chest radiographs in women.

Calcifications in the breast can overlie the lung fields and mimic pulmonary nodules. When assessing pulmonary nodules, prior imaging of the chest should always be assessed if available to determine if a lesion is new or has remained stable.

Given our patient’s age and 35-pack-year history of smoking, apparent pulmonary lesions caused concern and prompted chest CT to clarify the diagnosis. However, if the patient has no risk factors for lung malignancy, it can be safe to proceed with mammography.

By including breast calcifications in the differential diagnosis of apparent pulmonary nodules on chest radiography, the clinician can approach the case differently and inquire about a history of fibroadenomas and prior mammograms before pursuing a further workup. This can avoid unnecessary radiation exposure, the costs of CT, and apprehension in the patient raised by unwarranted concern for malignancy.

Acute pancreatitis accounted for more than 300,000 admissions and $2.6 billion in associated healthcare costs in the United States in 2012.¹ First-line management is early aggressive fluid resuscitation and analgesics for pain control. Guidelines recommend estimating the clinical severity of each attack using a validated scoring system such as the Bedside Index of Severity in Acute Pancreatitis.² Clinically severe pancreatitis is associated with necrosis.

Acute pancreatitis results from inappropriate activation of zymogens and subsequent auto­digestion of the pancreas by its own enzymes. Though necrotizing pancreatitis is thought to be an ischemic complication, its pathogenesis is not completely understood. Necrosis increases the morbidity and mortality risk of acute pancreatitis because of its association with organ failure and infectious complications. As such, patients with necrotizing pancreatitis may need admission to the intensive care unit, nutritional support, antibiotics, and radiologic, endoscopic, or surgical interventions.

Here, we review current evidence regarding the diagnosis and management of necrotizing pancreatitis.

PROPER TERMINOLOGY HELPS COLLABORATION

Managing necrotizing pancreatitis requires the combined efforts of internists, gastroenterologists, radiologists, and surgeons. This collaboration is aided by proper terminology.

A classification system was devised in Atlanta, GA, in 1992 to facilitate communication and interdisciplinary collaboration.³ Severe pancreatitis was differentiated from mild by the presence of organ failure or the complications of pseudocyst, necrosis, or abscess.

The original Atlanta classification had several limitations. First, the terminology for fluid collections was ambiguous and frequently misused. Second, the assessment of clinical severity required either the Ranson score or the Acute Physiology and Chronic Health Evaluation II score, both of which are complex and have other limitations. Finally, advances in imaging and treatment have rendered the original Atlanta nomenclature obsolete.

In 2012, the Acute Pancreatitis Classification Working Group issued a revised Atlanta classification that modernized the terminology pertaining to natural history, severity, imaging features, and complications. It divides the natural course of acute pancreatitis into early and late phases.⁴

Early vs late phase

In the early phase, findings on computed tomography (CT) neither correlate with clinical severity nor alter clinical management.⁶ Thus, early imaging is not indicated unless there is diagnostic uncertainty, lack of response to appropriate treatment, or sudden deterioration.

Moderate pancreatitis describes patients with pancreatic necrosis with or without transient organ failure (organ dysfunction for ≤ 48 hours).

Severe pancreatitis is defined by pancreatic necrosis and persistent organ dysfunction.⁴ It may be accompanied by pancreatic and peripancreatic fluid collections; bacteremia and sepsis can occur in association with infection of necrotic collections.

Interstitial edematous pancreatitis vs necrotizing pancreatitis

The revised Atlanta classification maintains the original classification of acute pancreatitis into 2 main categories: interstitial edematous pancreatitis and necrotizing pancreatitis.

Necrotizing pancreatitis is further divided into 3 subtypes based on extent and location of necrosis:

• Parenchymal necrosis alone (5% of cases)
• Necrosis of peripancreatic fat alone (20%)
• Necrosis of both parenchyma and peripancreatic fat (75%).

Peripancreatic involvement is commonly found in the mesentery, peripancreatic and distant retroperitoneum, and lesser sac.

Of the three subtypes, peripancreatic necrosis has the best prognosis. However, all of the subtypes of necrotizing pancreatitis are associated with poorer outcomes than interstitial edematous pancreatitis.

Fluid collections

Acute pancreatic fluid collections contain exclusively nonsolid components without an inflammatory wall and are typically found in the peripancreatic fat. These collections often resolve without intervention as the patient recovers. If they persist beyond 4 weeks and develop a nonepithelialized, fibrous wall, they become pseudocysts. Intervention is generally not recommended for pseudocysts unless they are symptomatic.

Radiographic imaging is not usually necessary to diagnose acute pancreatitis. However, it can be a valuable tool to clarify an ambiguous presentation, determine severity, and identify complications.

The timing and appropriate type of imaging are integral to obtaining useful data. Any imaging obtained in acute pancreatitis to evaluate necrosis should be performed at least 3 to 5 days from the initial symptom onset; if imaging is obtained before 72 hours, necrosis cannot be confidently excluded.⁸

COMPUTED TOMOGRAPHY

CT is the imaging test of choice when evaluating acute pancreatitis. In addition, almost all percutaneous interventions are performed with CT guidance. The Balthazar score is the most well-known CT severity index. It is calculated based on the degree of inflammation, acute fluid collections, and parenchymal necrosis.⁹ However, a modified severity index incorporates extrapancreatic complications such as ascites and vascular compromise and was found to more strongly correlate with outcomes than the standard Balthazar score.¹⁰

Contrast-enhanced CT is performed in 2 phases:

The pancreatic parenchymal phase

The pancreatic parenchymal or late arterial phase is obtained approximately 40 to 45 seconds after the start of the contrast bolus. It is used to detect necrosis in the early phase of acute pancreatitis and to assess the peripancreatic arteries for pseudoaneurysms in the late phase of acute pancreatitis.¹¹

Pancreatic necrosis appears as an area of decreased parenchymal enhancement, either well-defined or heterogeneous. The normal pancreatic parenchyma has a postcontrast enhancement pattern similar to that of the spleen. Parenchyma that does not enhance to the same degree is considered necrotic. The severity of necrosis is graded based on the percentage of the pancreas involved (< 30%, 30%–50%, or > 50%), and a higher percentage correlates with a worse outcome.^12,13

Peripancreatic necrosis is harder to detect, as there is no method to assess fat enhancement as there is with pancreatic parenchymal enhancement. In general, radiologists assume that heterogeneous peripancreatic changes, including areas of fat, fluid, and soft tissue attenuation, are consistent with peripancreatic necrosis. After 7 to 10 days, if these changes become more homogeneous and confluent with a more mass-like process, peripancreatic necrosis can be more confidently identified.^12,13

The portal venous phase

The later, portal venous phase of the scan is obtained approximately 70 seconds after the start of the contrast bolus. It is used to detect and characterize fluid collections and venous complications of the disease.

Drawbacks of CT

A drawback of CT is the need for iodinated intravenous contrast media, which in severely ill patients may precipitate or worsen pre-existing acute kidney injury.

Further, several studies have shown that findings on CT rarely alter the management of patients in the early phase of acute pancreatitis and in fact may be an overuse of medical resources.¹⁴ Unless there are confounding clinical signs or symptoms, CT should be delayed for at least 72 hours.^9,10,14,15

MAGNETIC RESONANCE IMAGING

Magnetic resonance imaging (MRI) is not a first-line imaging test in this disease because it is not as available as CT and takes longer to perform—20 to 30 minutes. The patient must be evaluated for candidacy, as it is difficult for acutely ill patients to tolerate an examination that takes this long and requires them to hold their breath multiple times.

MRI is an appropriate alternative in patients who are pregnant or who have severe iodinated-contrast allergy. While contrast is necessary to detect pancreatic necrosis with CT, MRI can detect necrosis without the need for contrast in patients with acute kidney injury or severe chronic kidney disease. Also, MRI may be better in complicated cases requiring repeated imaging because it does not expose the patient to radiation.

On MRI, pancreatic necrosis appears as a heterogeneous area, owing to its liquid and solid components. Liquid components appear hyperintense, and solid components hypointense, on T2 fluid-weighted imaging. This ability to differentiate the components of a walled-off pancreatic necrosis can be useful in determining whether a collection requires drainage or debridement. MRI is also more sensitive for hemorrhagic complications, best seen on T1 fat-weighted images.^12,16

Magnetic resonance cholangiopancreatography is an excellent method for ductal evaluation through heavily T2-weighted imaging. It is more sensitive than CT for detecting common bile duct stones and can also detect pancreatic duct strictures or extravasation into fluid collections.¹⁶

SUPPORTIVE MANAGEMENT OF EARLY NECROTIZING PANCREATITIS

In the early phase of necrotizing pancreatitis, management is supportive with the primary aim of preventing intravascular volume depletion. Aggressive fluid resuscitation in the first 48 to 72 hours, pain control, and bowel rest are the mainstays of supportive therapy. Intensive care may be necessary if organ failure and hemodynamic instability accompany necrotizing pancreatitis.

Prophylactic antibiotic and antifungal therapy to prevent infected necrosis has been controversial. Recent studies of its utility have not yielded supportive results, and the American College of Gastroenterology and the Infectious Diseases Society of America no longer recommend it.^9,17 These medications should not be given unless concomitant cholangitis or extrapancreatic infection is clinically suspected.

Early enteral nutrition is recommended in patients in whom pancreatitis is predicted to be severe and in those not expected to resume oral intake within 5 to 7 days. Enteral nutrition most commonly involves bedside or endoscopic placement of a nasojejunal feeding tube and collaboration with a nutritionist to determine protein-caloric requirements.

Compared with enteral nutrition, total parenteral nutrition is associated with higher rates of infection, multiorgan dysfunction and failure, and death.¹⁸

Necrotizing pancreatitis is a defining complication of acute pancreatitis, and its presence alone indicates greater severity. However, superimposed complications may further worsen outcomes.

Infected pancreatic necrosis

Infection occurs in approximately 20% of patients with necrotizing pancreatitis and confers a mortality rate of 20% to 50%.¹⁹ Infected pancreatic necrosis occurs when gut organisms translocate into the nearby necrotic pancreatic and peripancreatic tissue. The most commonly identified organisms include Escherichia coli and Enterococcus species.²⁰

This complication usually manifests 2 to 4 weeks after symptom onset; earlier onset is uncommon to rare. It should be considered when the systemic inflammatory response syndrome persists or recurs after 10 days to 2 weeks. Systemic inflammatory response syndrome is also common in sterile necrotizing pancreatitis and sometimes in interstitial pancreatitis, particularly during the first week. However, its sudden appearance or resurgence, high spiking fevers, or worsening organ failure in the later phase (2–4 weeks) of pancreatitis should heighten suspicion of infected pancreatic necrosis.

Imaging may also help diagnose infection, and the presence of gas within a collection or region of necrosis is highly specific. However, the presence of gas is not completely sensitive for infection, as it is seen in only 12% to 22% of infected cases.

Before minimally invasive techniques became available, the diagnosis of infected pancreatic necrosis was confirmed by percutaneous CT-guided aspiration of the necrotic mass or collection for Gram stain and culture.

Antibiotic therapy is indicated in confirmed or suspected cases of infected pancreatic necrosis. Antibiotics with gram-negative coverage and appropriate penetration such as carbapenems, metronidazole, fluoroquinolones, and selected cephalosporins are most commonly used. Meropenem is the antibiotic of choice at our institution.

CT-guided fine-needle aspiration is often done if suspected infected pancreatic necrosis fails to respond to empiric antibiotic therapy.

Debridement or drainage. Generally, the diagnosis or suspicion of infected pancreatic necrosis (suggestive signs are high fever, elevated white blood cell count, and sepsis) warrants an intervention to debride or drain infected pancreatic tissue and control sepsis.²¹

While source control is integral to the successful treatment of infected pancreatic necrosis, antibiotic therapy may provide a bridge to intervention for critically ill patients by suppressing bacteremia and subsequent sepsis. A 2013 meta-analysis found that 324 of 409 patients with suspected infected pancreatic necrosis were successfully stabilized with antibiotic treatment.^21,22 The trend toward conservative management and promising outcomes with antibiotic therapy alone or with minimally invasive techniques has lessened the need for diagnostic CT-guided fine-needle aspiration.

Hemorrhage

Spontaneous hemorrhage into pancreatic necrosis is a rare but life-threatening complication. Because CT is almost always performed with contrast enhancement, this complication is rarely identified with imaging. The diagnosis is made by noting a drop in hemoglobin and hematocrit.

Hemorrhage into the retroperitoneum or the peritoneal cavity, or both, can occur when an inflammatory process erodes into a nearby artery. Luminal gastrointestinal bleeding can occur from gastric varices arising from splenic vein thrombosis and resulting left-sided portal hypertension, or from pseudoaneurysms. These can also bleed into the pancreatic duct (hemosuccus pancreaticus). Pseudoaneurysm is a later complication that occurs when an arterial wall (most commonly the splenic or gastroduodenal artery) is weakened by pancreatic enzymes.²³

Prompt recognition of hemorrhagic events and consultation with an interventional radiologist or surgeon are required to prevent death.

Inflammation and abdominal compartment syndrome

Inflammation from necrotizing pancreatitis can cause further complications by blocking nearby structures. Reported complications include jaundice from biliary compression, hydronephrosis from ureteral compression, bowel obstruction, and gastric outlet obstruction.

Abdominal compartment syndrome is an increasingly recognized complication of acute pancreatitis. Abdominal pressure can rise due to a number of factors, including fluid collections, ascites, ileus, and overly aggressive fluid resuscitation.²⁴ Elevated abdominal pressure is associated with complications such as decreased respiratory compliance, increased peak airway pressure, decreased cardiac preload, hypotension, mesenteric and intestinal ischemia, feeding intolerance, and lower-extremity ischemia and thrombosis.

Patients with necrotizing pancreatitis who have abdominal compartment syndrome have a mortality rate 5 times higher than patients without abdominal compartment syndrome.²⁵

Abdominal pressures should be monitored using a bladder pressure sensor in critically ill or ventilated patients with acute pancreatitis. If the abdominal pressure rises above 20 mm Hg, medical and surgical interventions should be offered in a stepwise fashion to decrease it. Interventions include decompression by nasogastric and rectal tube, sedation or paralysis to relax abdominal wall tension, minimization of intravenous fluids, percutaneous drainage of ascites, and (rarely) surgical midline or subcostal laparotomy.

The treatment of necrotizing pancreatitis has changed rapidly, thanks to a growing experience with minimally invasive techniques.

Indications for intervention

Infected pancreatic necrosis is the primary indication for surgical, percutaneous, or endoscopic intervention.

In sterile necrosis, the threshold for intervention is less clear, and intervention is often reserved for patients who fail to clinically improve or who have intractable abdominal pain, gastric outlet obstruction, or fistulating disease.²⁶

In asymptomatic cases, intervention is almost never indicated regardless of the location or size of the necrotic area.

In walled-off pancreatic necrosis, less-invasive and less-morbid interventions such as endoscopic or percutaneous drainage or video-assisted retroperitoneal debridement can be done.

Timing of intervention

In the past, delaying intervention was thought to increase the risk of death. However, multiple studies have found that outcomes are often worse if intervention is done early, likely due to the lack of a fully formed fibrous wall or demarcation of the necrotic area.²⁷

If the patient remains clinically stable, it is best to delay intervention until at least 4 weeks after the index event to achieve optimal outcomes. Delay can often be achieved by antibiotic treatment to suppress bacteremia and endoscopic or percutaneous drainage of infected collections to control sepsis.

Open surgery

The gold-standard intervention for infected pancreatic necrosis or symptomatic sterile walled-off pancreatic necrosis is open necrosectomy. This involves exploratory laparotomy with blunt debridement of all visible necrotic pancreatic tissue.

Methods to facilitate later evacuation of residual infected fluid and debris vary widely. Multiple large-caliber drains can be placed to facilitate irrigation and drainage before closure of the abdominal fascia. As infected pancreatic necrosis carries the risk of contaminating the peritoneal cavity, the skin is often left open to heal by secondary intention. An interventional radiologist is frequently enlisted to place, exchange, or downsize drainage catheters.

Infected pancreatic necrosis or symptomatic sterile walled-off pancreatic necrosis often requires more than one operation to achieve satisfactory debridement.

The goals of open necrosectomy are to remove nonviable tissue and infection, preserve viable pancreatic tissue, eliminate fistulous connections, and minimize damage to local organs and vasculature.

Minimally invasive techniques

Video-assisted retroperitoneal debridement has been described as a hybrid between endoscopic and open retroperitoneal debridement.²⁸ This technique requires first placing a percutaneous catheter into the necrotic area through the left flank to create a retroperitoneal tract. A 5-cm incision is made and the necrotic space is entered using the drain for guidance. Necrotic tissue is carefully debrided under direct vision using a combination of forceps, irrigation, and suction. A laparoscopic port can also be introduced into the incision when the procedure can no longer be continued under direct vision.^29,30

Although not all patients are candidates for minimal-access surgery, it remains an evolving surgical option.

Endoscopic transmural debridement is another option for infected pancreatic necrosis and symptomatic walled-off pancreatic necrosis. Depending on the location of the necrotic area, an echoendoscope is passed to either the stomach or duodenum. Guided by endoscopic ultrasonography, a needle is passed into the collection, allowing subsequent fistula creation and stenting for internal drainage or debridement. In the past, this process required several steps, multiple devices, fluoroscopic guidance, and considerable time. But newer endoscopic lumen-apposing metal stents have been developed that can be placed in a single step without fluoroscopy. A slimmer endoscope can then be introduced into the necrotic cavity via the stent, and the necrotic debris can be debrided with endoscopic baskets, snares, forceps, and irrigation.^9,31

Similar to surgical necrosectomy, satisfactory debridement is not often obtained with a single procedure; 2 to 5 endoscopic procedures may be needed to achieve resolution. However, the luminal approach in endoscopic necrosectomy avoids the significant morbidity of major abdominal surgery and the potential for pancreaticocutaneous fistulae that may occur with drains.

In a randomized trial comparing endoscopic necrosectomy vs surgical necrosectomy (video-assisted retroperitoneal debridement and exploratory laparotomy),³² endoscopic necrosectomy showed less inflammatory response than surgical necrosectomy and had a lower risk of new-onset organ failure, bleeding, fistula formation, and death.³²

Selecting the best intervention for the individual patient

Given the multiple available techniques, selecting the best intervention for individual patients can be challenging. A team approach with input from a gastroenterologist, surgeon, and interventional radiologist is best when determining which technique would best suit each patient.

Surgical necrosectomy is still the treatment of choice for unstable patients with infected pancreatic necrosis or multiple, inaccessible collections, but current evidence suggests a different approach in stable infected pancreatic necrosis and symptomatic sterile walled-off pancreatic necrosis.

The Dutch Pancreatitis Group²⁸ randomized 88 patients with infected pancreatic necrosis or symptomatic walled-off pancreatic necrosis to open necrosectomy or a minimally invasive “step-up” approach consisting of up to 2 percutaneous drainage or endoscopic debridement procedures before escalation to video-assisted retroperitoneal debridement. The step-up approach resulted in lower rates of morbidity and death than surgical necrosectomy as first-line treatment. Furthermore, some patients in the step-up group avoided the need for surgery entirely.³⁰

Necrosis significantly increases rates of morbidity and mortality in acute pancreatitis. Hospitalists, general internists, and general surgeons are all on the front lines in identifying severe cases and consulting the appropriate specialists for optimal multidisciplinary care. Selective and appropriate timing of radiologic imaging is key, and a vital tool in the management of necrotizing pancreatitis.

While the primary indication for intervention is infected pancreatic necrosis, additional indications are symptomatic walled-off pancreatic necrosis secondary to intractable abdominal pain, bowel obstruction, and failure to thrive. As a result of improving technology and inpatient care, these patients may present with intractable symptoms in the outpatient setting rather than the inpatient setting. The onus is on the primary care physician to maintain a high level of suspicion and refer these patients to subspecialists as appropriate.

Open surgical necrosectomy remains an important approach for care of infected pancreatic necrosis or patients with intractable symptoms. A step-up approach starting with a minimally invasive procedure and escalating if the initial intervention is unsuccessful is gradually becoming the standard of care.

Acute pancreatitis accounted for more than 300,000 admissions and $2.6 billion in associated healthcare costs in the United States in 2012.¹ First-line management is early aggressive fluid resuscitation and analgesics for pain control. Guidelines recommend estimating the clinical severity of each attack using a validated scoring system such as the Bedside Index of Severity in Acute Pancreatitis.² Clinically severe pancreatitis is associated with necrosis.

Acute pancreatitis results from inappropriate activation of zymogens and subsequent auto­digestion of the pancreas by its own enzymes. Though necrotizing pancreatitis is thought to be an ischemic complication, its pathogenesis is not completely understood. Necrosis increases the morbidity and mortality risk of acute pancreatitis because of its association with organ failure and infectious complications. As such, patients with necrotizing pancreatitis may need admission to the intensive care unit, nutritional support, antibiotics, and radiologic, endoscopic, or surgical interventions.

Here, we review current evidence regarding the diagnosis and management of necrotizing pancreatitis.

PROPER TERMINOLOGY HELPS COLLABORATION

Managing necrotizing pancreatitis requires the combined efforts of internists, gastroenterologists, radiologists, and surgeons. This collaboration is aided by proper terminology.

A classification system was devised in Atlanta, GA, in 1992 to facilitate communication and interdisciplinary collaboration.³ Severe pancreatitis was differentiated from mild by the presence of organ failure or the complications of pseudocyst, necrosis, or abscess.

The original Atlanta classification had several limitations. First, the terminology for fluid collections was ambiguous and frequently misused. Second, the assessment of clinical severity required either the Ranson score or the Acute Physiology and Chronic Health Evaluation II score, both of which are complex and have other limitations. Finally, advances in imaging and treatment have rendered the original Atlanta nomenclature obsolete.

In 2012, the Acute Pancreatitis Classification Working Group issued a revised Atlanta classification that modernized the terminology pertaining to natural history, severity, imaging features, and complications. It divides the natural course of acute pancreatitis into early and late phases.⁴

Early vs late phase

In the early phase, findings on computed tomography (CT) neither correlate with clinical severity nor alter clinical management.⁶ Thus, early imaging is not indicated unless there is diagnostic uncertainty, lack of response to appropriate treatment, or sudden deterioration.

Moderate pancreatitis describes patients with pancreatic necrosis with or without transient organ failure (organ dysfunction for ≤ 48 hours).

Severe pancreatitis is defined by pancreatic necrosis and persistent organ dysfunction.⁴ It may be accompanied by pancreatic and peripancreatic fluid collections; bacteremia and sepsis can occur in association with infection of necrotic collections.

Interstitial edematous pancreatitis vs necrotizing pancreatitis

The revised Atlanta classification maintains the original classification of acute pancreatitis into 2 main categories: interstitial edematous pancreatitis and necrotizing pancreatitis.

Necrotizing pancreatitis is further divided into 3 subtypes based on extent and location of necrosis:

• Parenchymal necrosis alone (5% of cases)
• Necrosis of peripancreatic fat alone (20%)
• Necrosis of both parenchyma and peripancreatic fat (75%).

Peripancreatic involvement is commonly found in the mesentery, peripancreatic and distant retroperitoneum, and lesser sac.

Of the three subtypes, peripancreatic necrosis has the best prognosis. However, all of the subtypes of necrotizing pancreatitis are associated with poorer outcomes than interstitial edematous pancreatitis.

Fluid collections

Acute pancreatic fluid collections contain exclusively nonsolid components without an inflammatory wall and are typically found in the peripancreatic fat. These collections often resolve without intervention as the patient recovers. If they persist beyond 4 weeks and develop a nonepithelialized, fibrous wall, they become pseudocysts. Intervention is generally not recommended for pseudocysts unless they are symptomatic.

Radiographic imaging is not usually necessary to diagnose acute pancreatitis. However, it can be a valuable tool to clarify an ambiguous presentation, determine severity, and identify complications.

The timing and appropriate type of imaging are integral to obtaining useful data. Any imaging obtained in acute pancreatitis to evaluate necrosis should be performed at least 3 to 5 days from the initial symptom onset; if imaging is obtained before 72 hours, necrosis cannot be confidently excluded.⁸

COMPUTED TOMOGRAPHY

CT is the imaging test of choice when evaluating acute pancreatitis. In addition, almost all percutaneous interventions are performed with CT guidance. The Balthazar score is the most well-known CT severity index. It is calculated based on the degree of inflammation, acute fluid collections, and parenchymal necrosis.⁹ However, a modified severity index incorporates extrapancreatic complications such as ascites and vascular compromise and was found to more strongly correlate with outcomes than the standard Balthazar score.¹⁰

Contrast-enhanced CT is performed in 2 phases:

The pancreatic parenchymal phase

The pancreatic parenchymal or late arterial phase is obtained approximately 40 to 45 seconds after the start of the contrast bolus. It is used to detect necrosis in the early phase of acute pancreatitis and to assess the peripancreatic arteries for pseudoaneurysms in the late phase of acute pancreatitis.¹¹

Pancreatic necrosis appears as an area of decreased parenchymal enhancement, either well-defined or heterogeneous. The normal pancreatic parenchyma has a postcontrast enhancement pattern similar to that of the spleen. Parenchyma that does not enhance to the same degree is considered necrotic. The severity of necrosis is graded based on the percentage of the pancreas involved (< 30%, 30%–50%, or > 50%), and a higher percentage correlates with a worse outcome.^12,13

Peripancreatic necrosis is harder to detect, as there is no method to assess fat enhancement as there is with pancreatic parenchymal enhancement. In general, radiologists assume that heterogeneous peripancreatic changes, including areas of fat, fluid, and soft tissue attenuation, are consistent with peripancreatic necrosis. After 7 to 10 days, if these changes become more homogeneous and confluent with a more mass-like process, peripancreatic necrosis can be more confidently identified.^12,13

The portal venous phase

The later, portal venous phase of the scan is obtained approximately 70 seconds after the start of the contrast bolus. It is used to detect and characterize fluid collections and venous complications of the disease.

Drawbacks of CT

A drawback of CT is the need for iodinated intravenous contrast media, which in severely ill patients may precipitate or worsen pre-existing acute kidney injury.

Further, several studies have shown that findings on CT rarely alter the management of patients in the early phase of acute pancreatitis and in fact may be an overuse of medical resources.¹⁴ Unless there are confounding clinical signs or symptoms, CT should be delayed for at least 72 hours.^9,10,14,15

MAGNETIC RESONANCE IMAGING

Magnetic resonance imaging (MRI) is not a first-line imaging test in this disease because it is not as available as CT and takes longer to perform—20 to 30 minutes. The patient must be evaluated for candidacy, as it is difficult for acutely ill patients to tolerate an examination that takes this long and requires them to hold their breath multiple times.

MRI is an appropriate alternative in patients who are pregnant or who have severe iodinated-contrast allergy. While contrast is necessary to detect pancreatic necrosis with CT, MRI can detect necrosis without the need for contrast in patients with acute kidney injury or severe chronic kidney disease. Also, MRI may be better in complicated cases requiring repeated imaging because it does not expose the patient to radiation.

On MRI, pancreatic necrosis appears as a heterogeneous area, owing to its liquid and solid components. Liquid components appear hyperintense, and solid components hypointense, on T2 fluid-weighted imaging. This ability to differentiate the components of a walled-off pancreatic necrosis can be useful in determining whether a collection requires drainage or debridement. MRI is also more sensitive for hemorrhagic complications, best seen on T1 fat-weighted images.^12,16

Magnetic resonance cholangiopancreatography is an excellent method for ductal evaluation through heavily T2-weighted imaging. It is more sensitive than CT for detecting common bile duct stones and can also detect pancreatic duct strictures or extravasation into fluid collections.¹⁶

SUPPORTIVE MANAGEMENT OF EARLY NECROTIZING PANCREATITIS

In the early phase of necrotizing pancreatitis, management is supportive with the primary aim of preventing intravascular volume depletion. Aggressive fluid resuscitation in the first 48 to 72 hours, pain control, and bowel rest are the mainstays of supportive therapy. Intensive care may be necessary if organ failure and hemodynamic instability accompany necrotizing pancreatitis.

Prophylactic antibiotic and antifungal therapy to prevent infected necrosis has been controversial. Recent studies of its utility have not yielded supportive results, and the American College of Gastroenterology and the Infectious Diseases Society of America no longer recommend it.^9,17 These medications should not be given unless concomitant cholangitis or extrapancreatic infection is clinically suspected.

Early enteral nutrition is recommended in patients in whom pancreatitis is predicted to be severe and in those not expected to resume oral intake within 5 to 7 days. Enteral nutrition most commonly involves bedside or endoscopic placement of a nasojejunal feeding tube and collaboration with a nutritionist to determine protein-caloric requirements.

Compared with enteral nutrition, total parenteral nutrition is associated with higher rates of infection, multiorgan dysfunction and failure, and death.¹⁸

Necrotizing pancreatitis is a defining complication of acute pancreatitis, and its presence alone indicates greater severity. However, superimposed complications may further worsen outcomes.

Infected pancreatic necrosis

Infection occurs in approximately 20% of patients with necrotizing pancreatitis and confers a mortality rate of 20% to 50%.¹⁹ Infected pancreatic necrosis occurs when gut organisms translocate into the nearby necrotic pancreatic and peripancreatic tissue. The most commonly identified organisms include Escherichia coli and Enterococcus species.²⁰

This complication usually manifests 2 to 4 weeks after symptom onset; earlier onset is uncommon to rare. It should be considered when the systemic inflammatory response syndrome persists or recurs after 10 days to 2 weeks. Systemic inflammatory response syndrome is also common in sterile necrotizing pancreatitis and sometimes in interstitial pancreatitis, particularly during the first week. However, its sudden appearance or resurgence, high spiking fevers, or worsening organ failure in the later phase (2–4 weeks) of pancreatitis should heighten suspicion of infected pancreatic necrosis.

Imaging may also help diagnose infection, and the presence of gas within a collection or region of necrosis is highly specific. However, the presence of gas is not completely sensitive for infection, as it is seen in only 12% to 22% of infected cases.

Before minimally invasive techniques became available, the diagnosis of infected pancreatic necrosis was confirmed by percutaneous CT-guided aspiration of the necrotic mass or collection for Gram stain and culture.

Antibiotic therapy is indicated in confirmed or suspected cases of infected pancreatic necrosis. Antibiotics with gram-negative coverage and appropriate penetration such as carbapenems, metronidazole, fluoroquinolones, and selected cephalosporins are most commonly used. Meropenem is the antibiotic of choice at our institution.

CT-guided fine-needle aspiration is often done if suspected infected pancreatic necrosis fails to respond to empiric antibiotic therapy.

Debridement or drainage. Generally, the diagnosis or suspicion of infected pancreatic necrosis (suggestive signs are high fever, elevated white blood cell count, and sepsis) warrants an intervention to debride or drain infected pancreatic tissue and control sepsis.²¹

While source control is integral to the successful treatment of infected pancreatic necrosis, antibiotic therapy may provide a bridge to intervention for critically ill patients by suppressing bacteremia and subsequent sepsis. A 2013 meta-analysis found that 324 of 409 patients with suspected infected pancreatic necrosis were successfully stabilized with antibiotic treatment.^21,22 The trend toward conservative management and promising outcomes with antibiotic therapy alone or with minimally invasive techniques has lessened the need for diagnostic CT-guided fine-needle aspiration.

Hemorrhage

Spontaneous hemorrhage into pancreatic necrosis is a rare but life-threatening complication. Because CT is almost always performed with contrast enhancement, this complication is rarely identified with imaging. The diagnosis is made by noting a drop in hemoglobin and hematocrit.

Hemorrhage into the retroperitoneum or the peritoneal cavity, or both, can occur when an inflammatory process erodes into a nearby artery. Luminal gastrointestinal bleeding can occur from gastric varices arising from splenic vein thrombosis and resulting left-sided portal hypertension, or from pseudoaneurysms. These can also bleed into the pancreatic duct (hemosuccus pancreaticus). Pseudoaneurysm is a later complication that occurs when an arterial wall (most commonly the splenic or gastroduodenal artery) is weakened by pancreatic enzymes.²³

Prompt recognition of hemorrhagic events and consultation with an interventional radiologist or surgeon are required to prevent death.

Inflammation and abdominal compartment syndrome

Inflammation from necrotizing pancreatitis can cause further complications by blocking nearby structures. Reported complications include jaundice from biliary compression, hydronephrosis from ureteral compression, bowel obstruction, and gastric outlet obstruction.

Abdominal compartment syndrome is an increasingly recognized complication of acute pancreatitis. Abdominal pressure can rise due to a number of factors, including fluid collections, ascites, ileus, and overly aggressive fluid resuscitation.²⁴ Elevated abdominal pressure is associated with complications such as decreased respiratory compliance, increased peak airway pressure, decreased cardiac preload, hypotension, mesenteric and intestinal ischemia, feeding intolerance, and lower-extremity ischemia and thrombosis.

Patients with necrotizing pancreatitis who have abdominal compartment syndrome have a mortality rate 5 times higher than patients without abdominal compartment syndrome.²⁵

Abdominal pressures should be monitored using a bladder pressure sensor in critically ill or ventilated patients with acute pancreatitis. If the abdominal pressure rises above 20 mm Hg, medical and surgical interventions should be offered in a stepwise fashion to decrease it. Interventions include decompression by nasogastric and rectal tube, sedation or paralysis to relax abdominal wall tension, minimization of intravenous fluids, percutaneous drainage of ascites, and (rarely) surgical midline or subcostal laparotomy.

The treatment of necrotizing pancreatitis has changed rapidly, thanks to a growing experience with minimally invasive techniques.

Indications for intervention

Infected pancreatic necrosis is the primary indication for surgical, percutaneous, or endoscopic intervention.

In sterile necrosis, the threshold for intervention is less clear, and intervention is often reserved for patients who fail to clinically improve or who have intractable abdominal pain, gastric outlet obstruction, or fistulating disease.²⁶

In asymptomatic cases, intervention is almost never indicated regardless of the location or size of the necrotic area.

In walled-off pancreatic necrosis, less-invasive and less-morbid interventions such as endoscopic or percutaneous drainage or video-assisted retroperitoneal debridement can be done.

Timing of intervention

In the past, delaying intervention was thought to increase the risk of death. However, multiple studies have found that outcomes are often worse if intervention is done early, likely due to the lack of a fully formed fibrous wall or demarcation of the necrotic area.²⁷

If the patient remains clinically stable, it is best to delay intervention until at least 4 weeks after the index event to achieve optimal outcomes. Delay can often be achieved by antibiotic treatment to suppress bacteremia and endoscopic or percutaneous drainage of infected collections to control sepsis.

Open surgery

The gold-standard intervention for infected pancreatic necrosis or symptomatic sterile walled-off pancreatic necrosis is open necrosectomy. This involves exploratory laparotomy with blunt debridement of all visible necrotic pancreatic tissue.

Methods to facilitate later evacuation of residual infected fluid and debris vary widely. Multiple large-caliber drains can be placed to facilitate irrigation and drainage before closure of the abdominal fascia. As infected pancreatic necrosis carries the risk of contaminating the peritoneal cavity, the skin is often left open to heal by secondary intention. An interventional radiologist is frequently enlisted to place, exchange, or downsize drainage catheters.

Infected pancreatic necrosis or symptomatic sterile walled-off pancreatic necrosis often requires more than one operation to achieve satisfactory debridement.

The goals of open necrosectomy are to remove nonviable tissue and infection, preserve viable pancreatic tissue, eliminate fistulous connections, and minimize damage to local organs and vasculature.

Minimally invasive techniques

Video-assisted retroperitoneal debridement has been described as a hybrid between endoscopic and open retroperitoneal debridement.²⁸ This technique requires first placing a percutaneous catheter into the necrotic area through the left flank to create a retroperitoneal tract. A 5-cm incision is made and the necrotic space is entered using the drain for guidance. Necrotic tissue is carefully debrided under direct vision using a combination of forceps, irrigation, and suction. A laparoscopic port can also be introduced into the incision when the procedure can no longer be continued under direct vision.^29,30

Although not all patients are candidates for minimal-access surgery, it remains an evolving surgical option.

Endoscopic transmural debridement is another option for infected pancreatic necrosis and symptomatic walled-off pancreatic necrosis. Depending on the location of the necrotic area, an echoendoscope is passed to either the stomach or duodenum. Guided by endoscopic ultrasonography, a needle is passed into the collection, allowing subsequent fistula creation and stenting for internal drainage or debridement. In the past, this process required several steps, multiple devices, fluoroscopic guidance, and considerable time. But newer endoscopic lumen-apposing metal stents have been developed that can be placed in a single step without fluoroscopy. A slimmer endoscope can then be introduced into the necrotic cavity via the stent, and the necrotic debris can be debrided with endoscopic baskets, snares, forceps, and irrigation.^9,31

Similar to surgical necrosectomy, satisfactory debridement is not often obtained with a single procedure; 2 to 5 endoscopic procedures may be needed to achieve resolution. However, the luminal approach in endoscopic necrosectomy avoids the significant morbidity of major abdominal surgery and the potential for pancreaticocutaneous fistulae that may occur with drains.

In a randomized trial comparing endoscopic necrosectomy vs surgical necrosectomy (video-assisted retroperitoneal debridement and exploratory laparotomy),³² endoscopic necrosectomy showed less inflammatory response than surgical necrosectomy and had a lower risk of new-onset organ failure, bleeding, fistula formation, and death.³²

Selecting the best intervention for the individual patient

Given the multiple available techniques, selecting the best intervention for individual patients can be challenging. A team approach with input from a gastroenterologist, surgeon, and interventional radiologist is best when determining which technique would best suit each patient.

Surgical necrosectomy is still the treatment of choice for unstable patients with infected pancreatic necrosis or multiple, inaccessible collections, but current evidence suggests a different approach in stable infected pancreatic necrosis and symptomatic sterile walled-off pancreatic necrosis.

The Dutch Pancreatitis Group²⁸ randomized 88 patients with infected pancreatic necrosis or symptomatic walled-off pancreatic necrosis to open necrosectomy or a minimally invasive “step-up” approach consisting of up to 2 percutaneous drainage or endoscopic debridement procedures before escalation to video-assisted retroperitoneal debridement. The step-up approach resulted in lower rates of morbidity and death than surgical necrosectomy as first-line treatment. Furthermore, some patients in the step-up group avoided the need for surgery entirely.³⁰

Necrosis significantly increases rates of morbidity and mortality in acute pancreatitis. Hospitalists, general internists, and general surgeons are all on the front lines in identifying severe cases and consulting the appropriate specialists for optimal multidisciplinary care. Selective and appropriate timing of radiologic imaging is key, and a vital tool in the management of necrotizing pancreatitis.

While the primary indication for intervention is infected pancreatic necrosis, additional indications are symptomatic walled-off pancreatic necrosis secondary to intractable abdominal pain, bowel obstruction, and failure to thrive. As a result of improving technology and inpatient care, these patients may present with intractable symptoms in the outpatient setting rather than the inpatient setting. The onus is on the primary care physician to maintain a high level of suspicion and refer these patients to subspecialists as appropriate.

Open surgical necrosectomy remains an important approach for care of infected pancreatic necrosis or patients with intractable symptoms. A step-up approach starting with a minimally invasive procedure and escalating if the initial intervention is unsuccessful is gradually becoming the standard of care.

Acute pancreatitis accounted for more than 300,000 admissions and $2.6 billion in associated healthcare costs in the United States in 2012.¹ First-line management is early aggressive fluid resuscitation and analgesics for pain control. Guidelines recommend estimating the clinical severity of each attack using a validated scoring system such as the Bedside Index of Severity in Acute Pancreatitis.² Clinically severe pancreatitis is associated with necrosis.

Acute pancreatitis results from inappropriate activation of zymogens and subsequent auto­digestion of the pancreas by its own enzymes. Though necrotizing pancreatitis is thought to be an ischemic complication, its pathogenesis is not completely understood. Necrosis increases the morbidity and mortality risk of acute pancreatitis because of its association with organ failure and infectious complications. As such, patients with necrotizing pancreatitis may need admission to the intensive care unit, nutritional support, antibiotics, and radiologic, endoscopic, or surgical interventions.

Here, we review current evidence regarding the diagnosis and management of necrotizing pancreatitis.

PROPER TERMINOLOGY HELPS COLLABORATION

Managing necrotizing pancreatitis requires the combined efforts of internists, gastroenterologists, radiologists, and surgeons. This collaboration is aided by proper terminology.

A classification system was devised in Atlanta, GA, in 1992 to facilitate communication and interdisciplinary collaboration.³ Severe pancreatitis was differentiated from mild by the presence of organ failure or the complications of pseudocyst, necrosis, or abscess.

The original Atlanta classification had several limitations. First, the terminology for fluid collections was ambiguous and frequently misused. Second, the assessment of clinical severity required either the Ranson score or the Acute Physiology and Chronic Health Evaluation II score, both of which are complex and have other limitations. Finally, advances in imaging and treatment have rendered the original Atlanta nomenclature obsolete.

In 2012, the Acute Pancreatitis Classification Working Group issued a revised Atlanta classification that modernized the terminology pertaining to natural history, severity, imaging features, and complications. It divides the natural course of acute pancreatitis into early and late phases.⁴

Early vs late phase

In the early phase, findings on computed tomography (CT) neither correlate with clinical severity nor alter clinical management.⁶ Thus, early imaging is not indicated unless there is diagnostic uncertainty, lack of response to appropriate treatment, or sudden deterioration.

Moderate pancreatitis describes patients with pancreatic necrosis with or without transient organ failure (organ dysfunction for ≤ 48 hours).

Severe pancreatitis is defined by pancreatic necrosis and persistent organ dysfunction.⁴ It may be accompanied by pancreatic and peripancreatic fluid collections; bacteremia and sepsis can occur in association with infection of necrotic collections.

Interstitial edematous pancreatitis vs necrotizing pancreatitis

The revised Atlanta classification maintains the original classification of acute pancreatitis into 2 main categories: interstitial edematous pancreatitis and necrotizing pancreatitis.

Necrotizing pancreatitis is further divided into 3 subtypes based on extent and location of necrosis:

• Parenchymal necrosis alone (5% of cases)
• Necrosis of peripancreatic fat alone (20%)
• Necrosis of both parenchyma and peripancreatic fat (75%).

Peripancreatic involvement is commonly found in the mesentery, peripancreatic and distant retroperitoneum, and lesser sac.

Of the three subtypes, peripancreatic necrosis has the best prognosis. However, all of the subtypes of necrotizing pancreatitis are associated with poorer outcomes than interstitial edematous pancreatitis.

Fluid collections

Acute pancreatic fluid collections contain exclusively nonsolid components without an inflammatory wall and are typically found in the peripancreatic fat. These collections often resolve without intervention as the patient recovers. If they persist beyond 4 weeks and develop a nonepithelialized, fibrous wall, they become pseudocysts. Intervention is generally not recommended for pseudocysts unless they are symptomatic.

Radiographic imaging is not usually necessary to diagnose acute pancreatitis. However, it can be a valuable tool to clarify an ambiguous presentation, determine severity, and identify complications.

The timing and appropriate type of imaging are integral to obtaining useful data. Any imaging obtained in acute pancreatitis to evaluate necrosis should be performed at least 3 to 5 days from the initial symptom onset; if imaging is obtained before 72 hours, necrosis cannot be confidently excluded.⁸

COMPUTED TOMOGRAPHY

CT is the imaging test of choice when evaluating acute pancreatitis. In addition, almost all percutaneous interventions are performed with CT guidance. The Balthazar score is the most well-known CT severity index. It is calculated based on the degree of inflammation, acute fluid collections, and parenchymal necrosis.⁹ However, a modified severity index incorporates extrapancreatic complications such as ascites and vascular compromise and was found to more strongly correlate with outcomes than the standard Balthazar score.¹⁰

Contrast-enhanced CT is performed in 2 phases:

The pancreatic parenchymal phase

The pancreatic parenchymal or late arterial phase is obtained approximately 40 to 45 seconds after the start of the contrast bolus. It is used to detect necrosis in the early phase of acute pancreatitis and to assess the peripancreatic arteries for pseudoaneurysms in the late phase of acute pancreatitis.¹¹

Pancreatic necrosis appears as an area of decreased parenchymal enhancement, either well-defined or heterogeneous. The normal pancreatic parenchyma has a postcontrast enhancement pattern similar to that of the spleen. Parenchyma that does not enhance to the same degree is considered necrotic. The severity of necrosis is graded based on the percentage of the pancreas involved (< 30%, 30%–50%, or > 50%), and a higher percentage correlates with a worse outcome.^12,13

Peripancreatic necrosis is harder to detect, as there is no method to assess fat enhancement as there is with pancreatic parenchymal enhancement. In general, radiologists assume that heterogeneous peripancreatic changes, including areas of fat, fluid, and soft tissue attenuation, are consistent with peripancreatic necrosis. After 7 to 10 days, if these changes become more homogeneous and confluent with a more mass-like process, peripancreatic necrosis can be more confidently identified.^12,13

The portal venous phase

The later, portal venous phase of the scan is obtained approximately 70 seconds after the start of the contrast bolus. It is used to detect and characterize fluid collections and venous complications of the disease.

Drawbacks of CT

A drawback of CT is the need for iodinated intravenous contrast media, which in severely ill patients may precipitate or worsen pre-existing acute kidney injury.

Further, several studies have shown that findings on CT rarely alter the management of patients in the early phase of acute pancreatitis and in fact may be an overuse of medical resources.¹⁴ Unless there are confounding clinical signs or symptoms, CT should be delayed for at least 72 hours.^9,10,14,15

MAGNETIC RESONANCE IMAGING

Magnetic resonance imaging (MRI) is not a first-line imaging test in this disease because it is not as available as CT and takes longer to perform—20 to 30 minutes. The patient must be evaluated for candidacy, as it is difficult for acutely ill patients to tolerate an examination that takes this long and requires them to hold their breath multiple times.

MRI is an appropriate alternative in patients who are pregnant or who have severe iodinated-contrast allergy. While contrast is necessary to detect pancreatic necrosis with CT, MRI can detect necrosis without the need for contrast in patients with acute kidney injury or severe chronic kidney disease. Also, MRI may be better in complicated cases requiring repeated imaging because it does not expose the patient to radiation.

On MRI, pancreatic necrosis appears as a heterogeneous area, owing to its liquid and solid components. Liquid components appear hyperintense, and solid components hypointense, on T2 fluid-weighted imaging. This ability to differentiate the components of a walled-off pancreatic necrosis can be useful in determining whether a collection requires drainage or debridement. MRI is also more sensitive for hemorrhagic complications, best seen on T1 fat-weighted images.^12,16

Magnetic resonance cholangiopancreatography is an excellent method for ductal evaluation through heavily T2-weighted imaging. It is more sensitive than CT for detecting common bile duct stones and can also detect pancreatic duct strictures or extravasation into fluid collections.¹⁶

SUPPORTIVE MANAGEMENT OF EARLY NECROTIZING PANCREATITIS

In the early phase of necrotizing pancreatitis, management is supportive with the primary aim of preventing intravascular volume depletion. Aggressive fluid resuscitation in the first 48 to 72 hours, pain control, and bowel rest are the mainstays of supportive therapy. Intensive care may be necessary if organ failure and hemodynamic instability accompany necrotizing pancreatitis.

Prophylactic antibiotic and antifungal therapy to prevent infected necrosis has been controversial. Recent studies of its utility have not yielded supportive results, and the American College of Gastroenterology and the Infectious Diseases Society of America no longer recommend it.^9,17 These medications should not be given unless concomitant cholangitis or extrapancreatic infection is clinically suspected.

Early enteral nutrition is recommended in patients in whom pancreatitis is predicted to be severe and in those not expected to resume oral intake within 5 to 7 days. Enteral nutrition most commonly involves bedside or endoscopic placement of a nasojejunal feeding tube and collaboration with a nutritionist to determine protein-caloric requirements.

Compared with enteral nutrition, total parenteral nutrition is associated with higher rates of infection, multiorgan dysfunction and failure, and death.¹⁸

Necrotizing pancreatitis is a defining complication of acute pancreatitis, and its presence alone indicates greater severity. However, superimposed complications may further worsen outcomes.

Infected pancreatic necrosis

Infection occurs in approximately 20% of patients with necrotizing pancreatitis and confers a mortality rate of 20% to 50%.¹⁹ Infected pancreatic necrosis occurs when gut organisms translocate into the nearby necrotic pancreatic and peripancreatic tissue. The most commonly identified organisms include Escherichia coli and Enterococcus species.²⁰

This complication usually manifests 2 to 4 weeks after symptom onset; earlier onset is uncommon to rare. It should be considered when the systemic inflammatory response syndrome persists or recurs after 10 days to 2 weeks. Systemic inflammatory response syndrome is also common in sterile necrotizing pancreatitis and sometimes in interstitial pancreatitis, particularly during the first week. However, its sudden appearance or resurgence, high spiking fevers, or worsening organ failure in the later phase (2–4 weeks) of pancreatitis should heighten suspicion of infected pancreatic necrosis.

Imaging may also help diagnose infection, and the presence of gas within a collection or region of necrosis is highly specific. However, the presence of gas is not completely sensitive for infection, as it is seen in only 12% to 22% of infected cases.

Before minimally invasive techniques became available, the diagnosis of infected pancreatic necrosis was confirmed by percutaneous CT-guided aspiration of the necrotic mass or collection for Gram stain and culture.

Antibiotic therapy is indicated in confirmed or suspected cases of infected pancreatic necrosis. Antibiotics with gram-negative coverage and appropriate penetration such as carbapenems, metronidazole, fluoroquinolones, and selected cephalosporins are most commonly used. Meropenem is the antibiotic of choice at our institution.

CT-guided fine-needle aspiration is often done if suspected infected pancreatic necrosis fails to respond to empiric antibiotic therapy.

Debridement or drainage. Generally, the diagnosis or suspicion of infected pancreatic necrosis (suggestive signs are high fever, elevated white blood cell count, and sepsis) warrants an intervention to debride or drain infected pancreatic tissue and control sepsis.²¹

While source control is integral to the successful treatment of infected pancreatic necrosis, antibiotic therapy may provide a bridge to intervention for critically ill patients by suppressing bacteremia and subsequent sepsis. A 2013 meta-analysis found that 324 of 409 patients with suspected infected pancreatic necrosis were successfully stabilized with antibiotic treatment.^21,22 The trend toward conservative management and promising outcomes with antibiotic therapy alone or with minimally invasive techniques has lessened the need for diagnostic CT-guided fine-needle aspiration.

Hemorrhage

Spontaneous hemorrhage into pancreatic necrosis is a rare but life-threatening complication. Because CT is almost always performed with contrast enhancement, this complication is rarely identified with imaging. The diagnosis is made by noting a drop in hemoglobin and hematocrit.

Hemorrhage into the retroperitoneum or the peritoneal cavity, or both, can occur when an inflammatory process erodes into a nearby artery. Luminal gastrointestinal bleeding can occur from gastric varices arising from splenic vein thrombosis and resulting left-sided portal hypertension, or from pseudoaneurysms. These can also bleed into the pancreatic duct (hemosuccus pancreaticus). Pseudoaneurysm is a later complication that occurs when an arterial wall (most commonly the splenic or gastroduodenal artery) is weakened by pancreatic enzymes.²³

Prompt recognition of hemorrhagic events and consultation with an interventional radiologist or surgeon are required to prevent death.

Inflammation and abdominal compartment syndrome

Inflammation from necrotizing pancreatitis can cause further complications by blocking nearby structures. Reported complications include jaundice from biliary compression, hydronephrosis from ureteral compression, bowel obstruction, and gastric outlet obstruction.

Abdominal compartment syndrome is an increasingly recognized complication of acute pancreatitis. Abdominal pressure can rise due to a number of factors, including fluid collections, ascites, ileus, and overly aggressive fluid resuscitation.²⁴ Elevated abdominal pressure is associated with complications such as decreased respiratory compliance, increased peak airway pressure, decreased cardiac preload, hypotension, mesenteric and intestinal ischemia, feeding intolerance, and lower-extremity ischemia and thrombosis.

Patients with necrotizing pancreatitis who have abdominal compartment syndrome have a mortality rate 5 times higher than patients without abdominal compartment syndrome.²⁵

Abdominal pressures should be monitored using a bladder pressure sensor in critically ill or ventilated patients with acute pancreatitis. If the abdominal pressure rises above 20 mm Hg, medical and surgical interventions should be offered in a stepwise fashion to decrease it. Interventions include decompression by nasogastric and rectal tube, sedation or paralysis to relax abdominal wall tension, minimization of intravenous fluids, percutaneous drainage of ascites, and (rarely) surgical midline or subcostal laparotomy.

The treatment of necrotizing pancreatitis has changed rapidly, thanks to a growing experience with minimally invasive techniques.

Indications for intervention

Infected pancreatic necrosis is the primary indication for surgical, percutaneous, or endoscopic intervention.

In sterile necrosis, the threshold for intervention is less clear, and intervention is often reserved for patients who fail to clinically improve or who have intractable abdominal pain, gastric outlet obstruction, or fistulating disease.²⁶

In asymptomatic cases, intervention is almost never indicated regardless of the location or size of the necrotic area.

In walled-off pancreatic necrosis, less-invasive and less-morbid interventions such as endoscopic or percutaneous drainage or video-assisted retroperitoneal debridement can be done.

Timing of intervention

In the past, delaying intervention was thought to increase the risk of death. However, multiple studies have found that outcomes are often worse if intervention is done early, likely due to the lack of a fully formed fibrous wall or demarcation of the necrotic area.²⁷

If the patient remains clinically stable, it is best to delay intervention until at least 4 weeks after the index event to achieve optimal outcomes. Delay can often be achieved by antibiotic treatment to suppress bacteremia and endoscopic or percutaneous drainage of infected collections to control sepsis.

Open surgery

The gold-standard intervention for infected pancreatic necrosis or symptomatic sterile walled-off pancreatic necrosis is open necrosectomy. This involves exploratory laparotomy with blunt debridement of all visible necrotic pancreatic tissue.

Methods to facilitate later evacuation of residual infected fluid and debris vary widely. Multiple large-caliber drains can be placed to facilitate irrigation and drainage before closure of the abdominal fascia. As infected pancreatic necrosis carries the risk of contaminating the peritoneal cavity, the skin is often left open to heal by secondary intention. An interventional radiologist is frequently enlisted to place, exchange, or downsize drainage catheters.

Infected pancreatic necrosis or symptomatic sterile walled-off pancreatic necrosis often requires more than one operation to achieve satisfactory debridement.

The goals of open necrosectomy are to remove nonviable tissue and infection, preserve viable pancreatic tissue, eliminate fistulous connections, and minimize damage to local organs and vasculature.

Minimally invasive techniques

Video-assisted retroperitoneal debridement has been described as a hybrid between endoscopic and open retroperitoneal debridement.²⁸ This technique requires first placing a percutaneous catheter into the necrotic area through the left flank to create a retroperitoneal tract. A 5-cm incision is made and the necrotic space is entered using the drain for guidance. Necrotic tissue is carefully debrided under direct vision using a combination of forceps, irrigation, and suction. A laparoscopic port can also be introduced into the incision when the procedure can no longer be continued under direct vision.^29,30

Although not all patients are candidates for minimal-access surgery, it remains an evolving surgical option.

Endoscopic transmural debridement is another option for infected pancreatic necrosis and symptomatic walled-off pancreatic necrosis. Depending on the location of the necrotic area, an echoendoscope is passed to either the stomach or duodenum. Guided by endoscopic ultrasonography, a needle is passed into the collection, allowing subsequent fistula creation and stenting for internal drainage or debridement. In the past, this process required several steps, multiple devices, fluoroscopic guidance, and considerable time. But newer endoscopic lumen-apposing metal stents have been developed that can be placed in a single step without fluoroscopy. A slimmer endoscope can then be introduced into the necrotic cavity via the stent, and the necrotic debris can be debrided with endoscopic baskets, snares, forceps, and irrigation.^9,31

Similar to surgical necrosectomy, satisfactory debridement is not often obtained with a single procedure; 2 to 5 endoscopic procedures may be needed to achieve resolution. However, the luminal approach in endoscopic necrosectomy avoids the significant morbidity of major abdominal surgery and the potential for pancreaticocutaneous fistulae that may occur with drains.

In a randomized trial comparing endoscopic necrosectomy vs surgical necrosectomy (video-assisted retroperitoneal debridement and exploratory laparotomy),³² endoscopic necrosectomy showed less inflammatory response than surgical necrosectomy and had a lower risk of new-onset organ failure, bleeding, fistula formation, and death.³²

Selecting the best intervention for the individual patient

Given the multiple available techniques, selecting the best intervention for individual patients can be challenging. A team approach with input from a gastroenterologist, surgeon, and interventional radiologist is best when determining which technique would best suit each patient.

Surgical necrosectomy is still the treatment of choice for unstable patients with infected pancreatic necrosis or multiple, inaccessible collections, but current evidence suggests a different approach in stable infected pancreatic necrosis and symptomatic sterile walled-off pancreatic necrosis.

The Dutch Pancreatitis Group²⁸ randomized 88 patients with infected pancreatic necrosis or symptomatic walled-off pancreatic necrosis to open necrosectomy or a minimally invasive “step-up” approach consisting of up to 2 percutaneous drainage or endoscopic debridement procedures before escalation to video-assisted retroperitoneal debridement. The step-up approach resulted in lower rates of morbidity and death than surgical necrosectomy as first-line treatment. Furthermore, some patients in the step-up group avoided the need for surgery entirely.³⁰

Necrosis significantly increases rates of morbidity and mortality in acute pancreatitis. Hospitalists, general internists, and general surgeons are all on the front lines in identifying severe cases and consulting the appropriate specialists for optimal multidisciplinary care. Selective and appropriate timing of radiologic imaging is key, and a vital tool in the management of necrotizing pancreatitis.

While the primary indication for intervention is infected pancreatic necrosis, additional indications are symptomatic walled-off pancreatic necrosis secondary to intractable abdominal pain, bowel obstruction, and failure to thrive. As a result of improving technology and inpatient care, these patients may present with intractable symptoms in the outpatient setting rather than the inpatient setting. The onus is on the primary care physician to maintain a high level of suspicion and refer these patients to subspecialists as appropriate.

Open surgical necrosectomy remains an important approach for care of infected pancreatic necrosis or patients with intractable symptoms. A step-up approach starting with a minimally invasive procedure and escalating if the initial intervention is unsuccessful is gradually becoming the standard of care.

When a patient presents with suspected venous thromboembolism, ie, deep vein thrombosis or pulmonary embolism, what diagnostic tests are needed to confirm the diagnosis? The clinical signs and symptoms of venous thromboembolism are nonspecific and often difficult to interpret. Therefore, it is essential for clinicians to use a standardized, structured approach to diagnosis that incorporates clinical findings and laboratory testing, as well as judicious use of diagnostic imaging. But while information is important, clinicians must also strive to avoid unnecessary testing, not only to decrease costs, but also to avoid potential harm.

If the diagnosis is confirmed, does the patient need testing for an underlying thrombophilic disorder? Such screening is often considered after a thromboembolic event occurs. However, a growing body of evidence indicates that the results of thrombophilia testing can be misinterpreted and potentially harmful.¹ We need to understand the utility of this testing as well as when and how it should be used. Patients and thrombosis specialists should be involved in deciding whether to perform these tests.

In this article, we provide practical information about how to diagnose venous thromboembolism, including strategies to optimize testing in suspected cases. We also offer guidance on how to decide whether further thrombophilia testing is warranted.

COMMON AND SERIOUS

Venous thromboembolism is a major cause of morbidity and death. Approximately 900,000 cases of pulmonary embolism and deep vein thrombosis occur in the United States each year, causing 60,000 to 300,000 deaths,² with the number of cases projected to double over the next 40 years.³

INITIAL APPROACH: PRETEST PROBABILITY

Given the morbidity and mortality associated with venous thromboembolism, prompt recognition and diagnosis are imperative. Clinical diagnosis alone is insufficient, with confirmed disease found in only 15% to 25% of patients suspected of having venous thromboembolism.^4–8 Therefore, the pretest probability should be coupled with objective testing.

The Wells score shows good discrimination in the outpatient and emergency department settings, but it has been invalidated in the inpatient setting, and thus it should not be used in inpatients.¹⁰

LABORATORY TESTS FOR SUSPECTED VENOUS THROMBOEMBOLISM

Employing an understanding of diagnostic testing is fundamental to identifying patients with venous thromboembolism.

D-dimer is a byproduct of fibrinolysis.

D-dimer testing has very high sensitivity for venous thromboembolism (> 90%) but low specificity (about 50%), and levels can be elevated in a variety of situations such as advanced age, acute inflammation, and cancer.¹⁵ The standard threshold is 500 μg/L, but because the D-dimer level increases with age, some clinicians advocate using an age-adjusted threshold for patients age 50 or older (age in years × 10 μg/L) to increase the diagnostic yield.¹⁶

Of the laboratory tests for D-dimer, the enzyme-linked immunosorbent assay has the highest sensitivity and highest negative predictive value (100%) and may be preferred over the other test methodologies.¹⁷

With its high sensitivity, D-dimer testing is clinically useful for ruling out venous thromboembolism, particularly when the pretest probability is low, but it lacks the specificity required for diagnosing and treating the disease if positive. Thus, it is not useful for ruling in venous thromboembolism. If the patient has a high pretest probability, we can omit D-dimer testing in favor of imaging studies.

Other laboratory tests such as arterial blood gas and brain natriuretic peptide levels have been proposed as markers of pulmonary embolism, but studies suggest they have limited utility in predicting the presence of disease.^18,19

DIAGNOSTIC TESTS FOR DEEP VEIN THROMBOSIS

Ultrasonography

If the pretest probability of deep vein thrombosis is high or a D-dimer test is found to be positive, the next step in evaluation is compression ultrasonography. 

While some guidelines recommend scanning only the proximal leg, many facilities in the United States scan the whole leg, which may reveal distal deep vein thrombosis.²⁰ The clinical significance of isolated distal deep vein thrombosis is unknown, and a selective anticoagulation approach may be used if this condition is discovered. The 2012 and 2016 American College of Chest Physicians (ACCP) guidelines on diagnosis and management of venous thromboembolism address this topic.^20,21

Deep vein thrombosis in the arm should be evaluated in the same manner as in the lower extremities.

Venography

Invasive and therefore no longer often used, venography is considered the gold standard for diagnosing deep vein thrombosis. Computed tomographic (CT) or magnetic resonance (MR) venography is most useful if the patient has aberrant anatomy such as a deformity of the leg, or in situations where the use of ultrasonography is difficult or unreliable, such as in the setting of severe obesity. CT or MR venography may be considered when looking for thrombosis in noncompressible veins of the thorax and abdomen (eg, the subclavian vein, iliac vein, and inferior vena cava) if ultrasonography is negative but clinical suspicion is high. Venous-phase CT angiography is particularly useful in diagnosing deep vein thrombosis in the inferior vena cava and iliac vein when deep vein thrombosis is clinically suspected but cannot be visualized on duplex ultrasonography.

Computed tomography

Imaging is warranted in patients who have a high pretest probability of pulmonary embolism, or in whom the D-dimer assay was positive but the pretest probability was low or moderate.

Once the gold standard, pulmonary angiography is no longer recommended for the initial diagnosis of pulmonary embolism because it is invasive, often unavailable, less sophisticated, and more expensive than noninvasive imaging techniques such as CT angiography. It is still used, however, in catheter-directed thrombolysis.

Thus, multiphasic CT angiography, as guided by pretest probability and the D-dimer level, is the imaging test of choice in the evaluation of pulmonary embolism. It can also offer insight into thrombotic burden and can reveal concurrent or alternative diagnoses (eg, pneumonia).

Ventilation-perfusion scanning

When CT angiography is unavailable or the patient should not be exposed to contrast medium (eg, due to concern for contrast-induced nephropathy or contrast allergy), ventilation-perfusion (V/Q) scanning remains an option for ruling out pulmonary embolism.²²

Anderson et al²³ compared CT angiography and V/Q scanning in a study in 1,417 patients considered likely to have acute pulmonary embolism. Rates of symptomatic pulmonary embolism during 3-month follow-up were similar in patients who initially had negative results on V/Q scanning compared with those who initially had negative results on CT angiography. However, this study used single-detector CT scanners for one-third of the patients. Therefore, the results may have been different if current technology had been used.

Limitations of V/Q scanning include length of time to perform (30–45 minutes), cost, inability to identify other causes of symptoms, and difficulty with interpretation  when other pulmonary pathology is present (eg, lung infiltrate). V/Q scanning is helpful when negative but is often reported based on probability (low, intermediate, or high) and may not provide adequate guidance. Therefore, CT angiography should be used whenever possible for diagnosing pulmonary embolism.

Other tests for pulmonary embolism

Electrocardiography, transthoracic echocardiography, and chest radiography may aid in the search for alternative diagnoses and assess the degree of right heart strain as a sequela of pulmonary embolism, but they do not confirm the diagnosis.

ORDER IMAGING ONLY IF NEEDED

Diagnostic imaging can be optimized by avoiding unnecessary tests that carry both costs and clinical risks.

Most patients in whom acute pulmonary embolism is discovered will not need testing for deep vein thrombosis, as they will receive anticoagulation regardless. Similarly, many patients with acute symptomatic deep vein thrombosis do not need testing for pulmonary embolism with chest CT imaging, as they too will receive anticoagulation regardless.

Therefore, clinicians are encouraged to use diagnostic reasoning while practicing high-value care (including estimating pretest probability and measuring D-dimer when appropriate), ordering additional tests judiciously and only if indicated.

THROMBOEMBOLISM IS CONFIRMED—IS FURTHER TESTING WARRANTED?

Once acute venous thromboembolism is confirmed, key considerations include whether the event was provoked or unprovoked (ie, idiopathic) and whether the patient needs indefinite anticoagulation (eg, after 2 or more unprovoked events).

Was the event provoked or unprovoked?

Even in cases of unprovoked venous thromboembolism, no clear consensus exists as to which patients should be tested for thrombophilia. Experts do advocate, however, that it be done only in highly selected patients and that it be coordinated with the patient, family members, and an expert in this testing. Patients for whom further testing may be considered include those with venous thromboembolism in unusual sites (eg, the cavernous sinus), with warfarin-induced skin necrosis, or with recurrent pregnancy loss.

While screening for malignancy may seem prudent in the case of unexplained venous thromboembolism, the use of CT imaging for this purpose has been found to be of low yield. In one study,²⁴ it was not found to detect additional neoplasms, and it can lead to additional cost and no added benefit for patients.

The American Board of Internal Medicine’s Choosing Wisely campaign strongly recommends consultation with an expert in thrombophilia (eg, a hematologist) before testing.²⁵ Ordering multiple tests in bundles (hypercoagulability panels) is unlikely to alter management, could have a negative clinical impact on patients, and is generally not recommended.

The ‘4 Ps’ approach to testing

• Patient selection
• Pretest counseling
• Proper laboratory interpretation
• Provision of education and advice.

Importantly, testing should be reserved for patients in whom the pretest probability of the thrombophilic disease is moderate to high, such as testing for antiphospholipid antibody syndrome in patients with systemic lupus erythematosus or recurrent miscarriage.

Venous thromboembolism in a patient who is known to have a malignant disease does not typically warrant further thrombophilia testing, as the event was likely a sequela of the malignancy. The evaluation and management of venous thromboembolism with concurrent neoplasm is covered elsewhere.²¹

Thrombophilia testing should be approached the same regardless of whether the venous thromboembolism was diagnosed intentionally or incidentally. First, determine whether the thrombosis was provoked or unprovoked, then order additional tests only if indicated, as recommended. Alternative approaches such as forgoing anticoagulation (but performing serial imaging, if indicated) may be reasonable if the thrombus is deemed clinically irrelevant (eg, nonocclusive, asymptomatic, subsegmental pulmonary embolism in the absence of proximal deep vein thrombosis; isolated distal deep vein thrombosis).^25,27

It is still debatable whether the increasing incidence of asymptomatic pulmonary embolism due to enhanced sensitivity of noninvasive diagnostic imaging warrants a change in diagnostic approach.²⁸

FACTORS TO CONSIDER BEFORE THROMBOPHILIA TESTING

Important factors to consider before testing for thrombophilia are²⁹:

• How will the results affect the anticoagulation plan?
• How may the patient’s clinical status and medications influence the results?
• Has the patient expressed a desire to understand why venous thromboembolism occurred?
• Will the results have a potential impact on the patient’s family members?

How will the results of thrombophilia testing affect anticoagulation management?

Because the goal of any diagnostic test is to find out what type of care the patient needs, clinicians must determine whether knowledge of an underlying thrombophilia will alter the short-term or long-term anticoagulation therapy the patient is receiving for an acute venous thromboembolic event.

As most acute episodes of venous thromboembolism require an initial 3 months of anticoagulation (with the exception of some nonclinically relevant events such as isolated distal deep vein thrombosis without extension on reimaging), testing in the acute setting does not change the short-term management of anticoagulation. Many hospitals have advocated for outpatient-only thrombophilia testing (if testing does occur), as testing in the acute setting may render test results uninterpretable (see What factors can influence thrombophilia testing? below) and can inappropriately affect the long-term management of anticoagulation. We recommend against testing in the inpatient setting.

To determine the duration of anticoagulation, clinicians must balance the risk of recurrent venous thromboembolism and the risk of bleeding. If a patient is at significant risk of bleeding or does not tolerate anticoagulation, clinicians may consider stopping therapy instead of evaluating for thrombophilia. For patients with provoked venous thromboembolism, anticoagulation should generally be limited to 3 months, as the risk of recurrence does not outweigh the risk of bleeding with continued anticoagulation therapy.

Patients with unprovoked venous thromboembolism have a risk of recurrence twice as high as those with provoked venous thromboembolism and generally need a longer duration of anticoagulation.^30,31 Once a patient with an unprovoked venous thromboembolic event has completed the initial 3 months of anticoagulation, a formal risk-benefit evaluation should be performed to determine whether to continue it.

Up to 42% of patients with unprovoked venous thromboembolism may have 1 or more thrombotic disorders, and some clinicians believe that detecting an underlying thrombophilia will aid in decisions regarding duration of therapy.³² However, the risk of recurrent venous thromboembolism in these patients does not differ significantly from that in patients without an underlying thrombophilia.^33–35 As such, it has been suggested that the unprovoked character of the thrombotic event, rather than an underlying thrombophilia, determines the risk of future recurrence and should be used instead of testing to guide the duration of anticoagulation therapy.³²

For more information, see the 2016 ACCP guideline update on antithrombotic therapy for venous thromboembolism.²⁷

What factors can influence the results of thrombophilia testing?

For example, antithrombin is consumed during thrombus formation; therefore, antithrombin levels may be transiently suppressed in acute venous thromboembolism. Moreover, since antithrombin binds to unfractionated heparin, low-molecular-weight heparin, and fondaparinux and mediates their activity as anticoagulants, antithrombin levels may be decreased by heparin therapy.

Similarly, vitamin K antagonists (eg, warfarin) suppress protein C and S activity levels by inhibiting vitamin K epoxide reductase and may falsely indicate a protein C or S deficiency.

Direct oral anticoagulants can cause false-positive results on lupus anticoagulant assays (dilute Russell viper venom time, augmented partial thromboplastin time), raise protein C, protein S, and antithrombin activity levels, and normalize activated protein C resistance assays, leading to missed diagnoses.⁴¹

Since estrogen therapy and pregnancy lead to increases in C4b binding protein, resulting in decreased free protein S, these situations can result in clinicians falsely labeling patients as having congenital protein S deficiency when in fact the patient had a transient reduction in protein S levels.³³

Therefore, to optimize accuracy and interpretation of results, thrombophilia testing should ideally be performed when the patient:

• Is past the acute event and out of the hospital
• Is not pregnant
• Has received the required 3 months of anticoagulation and is off this therapy.

For warfarin, most recommendations say that testing should be performed after the patient has been off therapy for 2 to 6 weeks.⁴² Low-molecular-weight heparins and direct oral anticoagulants should be discontinued for at least 48 to 72 hours, or longer if the patient has kidney impairment, as these medications are renally eliminated.

Genetic tests such as factor V Leiden and prothrombin gene mutation are not affected by these factors and do not require repeat or confirmatory testing.

What if the patient or family wants to understand why an event occurred?

Some experts advocate thrombophilia testing of asymptomatic family members to identify carriers who may need prophylaxis against venous thromboembolism in high-risk situations such as pregnancy, oral contraceptive use, hospitalization, and surgery.²⁹ Asymptomatic family members of a first-degree relative with a history of venous thromboembolism have a 2 times higher risk of an index event.⁴³ Thus, it may be argued that these asymptomatic individuals should receive prophylactic measures in any high-risk situation, based on the family history itself rather than results of thrombophilia testing.

Occasionally, patients and family members want to know the cause of the thrombotic event and want to be tested. In these instances, pretest counseling for the patient and family about the potential implications of testing and shared decision-making between the provider and patient are of utmost importance.²⁹

What is the impact on family members if thrombophilia is diagnosed?

While positive test results can give patients some satisfaction, this knowledge may also cause unnecessary worry, as the patient knows he or she has a hematologic disorder and could possible die of venous thromboembolism.

Thrombophilia testing can have other adverse consequences. For example, while the Genetic Information Nondiscrimination Act of 2008 protects against denial of health insurance benefits based on genetic information, known carriers of thrombophilia may have trouble obtaining life or disability insurance.⁴⁴

Unfortunately, it is not uncommon for thrombophilia testing to be inappropriately performed, interpreted, or followed up. These suboptimal approaches can lead to unnecessary exposure to high-risk therapeutic anticoagulation, excessive durations of therapy, and labeling with an unconfirmed or incorrect diagnosis. Additionally, there are significant costs associated with thrombophilia testing, including the cost of the tests and anticoagulant medications and management of adverse events such as bleeding.

WHAT ARE THE ALTERNATIVES TO THROMBOPHILIA TESTING?

Because discovered thrombophilias (eg, factor V Leiden mutation, prothrombin gene mutation) have not consistently shown a strong correlation with increased recurrence of venous thromboembolism, alternative approaches are emerging to determine the duration of therapy for unprovoked events.

Clinical prediction tools based on patient characteristics and laboratory markers that are more consistently associated with recurrent venous thromboembolism (eg, male sex, persistently elevated D-dimer) have been developed to aid clinicians dealing with this challenging question. Several prediction tools are available:

The “Men Continue and HERDOO2” rule (HERDOO2 = hyperpigmentation, edema, or redness in either leg; D-dimer level ≥ 250 μg/L; obesity with body mass index ≥ 30 kg/m²; or older age, ≥ 65)⁴⁵

The DASH score (D-dimer, age, sex, and hormonal therapy)⁴⁶

The Vienna score,^47,48 at http://cemsiis.meduniwien.ac.at/en/kb/science-research/software/clinical-software/recurrent-vte/.

SUMMARY OF THROMBOPHILIA TESTING RECOMMENDATIONS

Test for thrombophilia only when…

• Discussing with a specialist (eg, hematologist) who has an understanding of thrombophilia
• Using the 4 Ps approach
• A patient requests testing to understand why a thrombotic event occurred, and the patient understands the implications of testing (ie, received counseling) for self and for family
• An expert deems identification of asymptomatic family members important for those who may be carriers of a detected thrombophilia
• The patient with a venous thromboembolic event has completed 3 months of anticoagulation and has been off anticoagulation for the appropriate length of time
• The results will change management.

Forgo thrombophilia testing when…

• A patient has a provoked venous thromboembolic event
• You do not intend to discontinue anticoagulation (ie, anticoagulation is indefinite)
• The patient is in the acute (eg, inpatient) setting
• The patient is on anticoagulants that may render test results uninterpretable
• The patient is pregnant or on oral contraceptives
• Use of alternative patient characteristics and laboratory markers to predict venous thromboembolism recurrence may be an option.

OPTIMIZING THE DIAGNOSIS

With the incidence of venous thromboembolism rapidly increasing, optimizing its diagnosis from both a financial and clinical perspective is becoming increasingly important. Clinicians should be familiar with the use of pretest probability scoring for venous thromboembolism, as well as which diagnostic tests are preferred if further workup is indicated. They should strive to minimize or avoid indiscriminate thrombophilia testing, which may lead to increased healthcare costs and patient exposure to potentially harmful anticoagulation.

Testing for thrombophilia should be based on whether a venous thromboembolic event was provoked or unprovoked. Patients with provoked venous thromboembolism or those receiving indefinite anticoagulation therapy should not be tested for thrombophilia. If testing is being considered in a patient with unprovoked venous thromboembolism, a specialist who is able to implement the 4 Ps approach should be consulted to ensure well-informed, shared decision-making with patients and family members.

When a patient presents with suspected venous thromboembolism, ie, deep vein thrombosis or pulmonary embolism, what diagnostic tests are needed to confirm the diagnosis? The clinical signs and symptoms of venous thromboembolism are nonspecific and often difficult to interpret. Therefore, it is essential for clinicians to use a standardized, structured approach to diagnosis that incorporates clinical findings and laboratory testing, as well as judicious use of diagnostic imaging. But while information is important, clinicians must also strive to avoid unnecessary testing, not only to decrease costs, but also to avoid potential harm.

If the diagnosis is confirmed, does the patient need testing for an underlying thrombophilic disorder? Such screening is often considered after a thromboembolic event occurs. However, a growing body of evidence indicates that the results of thrombophilia testing can be misinterpreted and potentially harmful.¹ We need to understand the utility of this testing as well as when and how it should be used. Patients and thrombosis specialists should be involved in deciding whether to perform these tests.

In this article, we provide practical information about how to diagnose venous thromboembolism, including strategies to optimize testing in suspected cases. We also offer guidance on how to decide whether further thrombophilia testing is warranted.

COMMON AND SERIOUS

Venous thromboembolism is a major cause of morbidity and death. Approximately 900,000 cases of pulmonary embolism and deep vein thrombosis occur in the United States each year, causing 60,000 to 300,000 deaths,² with the number of cases projected to double over the next 40 years.³

INITIAL APPROACH: PRETEST PROBABILITY

Given the morbidity and mortality associated with venous thromboembolism, prompt recognition and diagnosis are imperative. Clinical diagnosis alone is insufficient, with confirmed disease found in only 15% to 25% of patients suspected of having venous thromboembolism.^4–8 Therefore, the pretest probability should be coupled with objective testing.

The Wells score shows good discrimination in the outpatient and emergency department settings, but it has been invalidated in the inpatient setting, and thus it should not be used in inpatients.¹⁰

LABORATORY TESTS FOR SUSPECTED VENOUS THROMBOEMBOLISM

Employing an understanding of diagnostic testing is fundamental to identifying patients with venous thromboembolism.

D-dimer is a byproduct of fibrinolysis.

D-dimer testing has very high sensitivity for venous thromboembolism (> 90%) but low specificity (about 50%), and levels can be elevated in a variety of situations such as advanced age, acute inflammation, and cancer.¹⁵ The standard threshold is 500 μg/L, but because the D-dimer level increases with age, some clinicians advocate using an age-adjusted threshold for patients age 50 or older (age in years × 10 μg/L) to increase the diagnostic yield.¹⁶

Of the laboratory tests for D-dimer, the enzyme-linked immunosorbent assay has the highest sensitivity and highest negative predictive value (100%) and may be preferred over the other test methodologies.¹⁷

With its high sensitivity, D-dimer testing is clinically useful for ruling out venous thromboembolism, particularly when the pretest probability is low, but it lacks the specificity required for diagnosing and treating the disease if positive. Thus, it is not useful for ruling in venous thromboembolism. If the patient has a high pretest probability, we can omit D-dimer testing in favor of imaging studies.

Other laboratory tests such as arterial blood gas and brain natriuretic peptide levels have been proposed as markers of pulmonary embolism, but studies suggest they have limited utility in predicting the presence of disease.^18,19

DIAGNOSTIC TESTS FOR DEEP VEIN THROMBOSIS

Ultrasonography

If the pretest probability of deep vein thrombosis is high or a D-dimer test is found to be positive, the next step in evaluation is compression ultrasonography. 

While some guidelines recommend scanning only the proximal leg, many facilities in the United States scan the whole leg, which may reveal distal deep vein thrombosis.²⁰ The clinical significance of isolated distal deep vein thrombosis is unknown, and a selective anticoagulation approach may be used if this condition is discovered. The 2012 and 2016 American College of Chest Physicians (ACCP) guidelines on diagnosis and management of venous thromboembolism address this topic.^20,21

Deep vein thrombosis in the arm should be evaluated in the same manner as in the lower extremities.

Venography

Invasive and therefore no longer often used, venography is considered the gold standard for diagnosing deep vein thrombosis. Computed tomographic (CT) or magnetic resonance (MR) venography is most useful if the patient has aberrant anatomy such as a deformity of the leg, or in situations where the use of ultrasonography is difficult or unreliable, such as in the setting of severe obesity. CT or MR venography may be considered when looking for thrombosis in noncompressible veins of the thorax and abdomen (eg, the subclavian vein, iliac vein, and inferior vena cava) if ultrasonography is negative but clinical suspicion is high. Venous-phase CT angiography is particularly useful in diagnosing deep vein thrombosis in the inferior vena cava and iliac vein when deep vein thrombosis is clinically suspected but cannot be visualized on duplex ultrasonography.

Computed tomography

Imaging is warranted in patients who have a high pretest probability of pulmonary embolism, or in whom the D-dimer assay was positive but the pretest probability was low or moderate.

Once the gold standard, pulmonary angiography is no longer recommended for the initial diagnosis of pulmonary embolism because it is invasive, often unavailable, less sophisticated, and more expensive than noninvasive imaging techniques such as CT angiography. It is still used, however, in catheter-directed thrombolysis.

Thus, multiphasic CT angiography, as guided by pretest probability and the D-dimer level, is the imaging test of choice in the evaluation of pulmonary embolism. It can also offer insight into thrombotic burden and can reveal concurrent or alternative diagnoses (eg, pneumonia).

Ventilation-perfusion scanning

When CT angiography is unavailable or the patient should not be exposed to contrast medium (eg, due to concern for contrast-induced nephropathy or contrast allergy), ventilation-perfusion (V/Q) scanning remains an option for ruling out pulmonary embolism.²²

Anderson et al²³ compared CT angiography and V/Q scanning in a study in 1,417 patients considered likely to have acute pulmonary embolism. Rates of symptomatic pulmonary embolism during 3-month follow-up were similar in patients who initially had negative results on V/Q scanning compared with those who initially had negative results on CT angiography. However, this study used single-detector CT scanners for one-third of the patients. Therefore, the results may have been different if current technology had been used.

Limitations of V/Q scanning include length of time to perform (30–45 minutes), cost, inability to identify other causes of symptoms, and difficulty with interpretation  when other pulmonary pathology is present (eg, lung infiltrate). V/Q scanning is helpful when negative but is often reported based on probability (low, intermediate, or high) and may not provide adequate guidance. Therefore, CT angiography should be used whenever possible for diagnosing pulmonary embolism.

Other tests for pulmonary embolism

Electrocardiography, transthoracic echocardiography, and chest radiography may aid in the search for alternative diagnoses and assess the degree of right heart strain as a sequela of pulmonary embolism, but they do not confirm the diagnosis.

ORDER IMAGING ONLY IF NEEDED

Diagnostic imaging can be optimized by avoiding unnecessary tests that carry both costs and clinical risks.

Most patients in whom acute pulmonary embolism is discovered will not need testing for deep vein thrombosis, as they will receive anticoagulation regardless. Similarly, many patients with acute symptomatic deep vein thrombosis do not need testing for pulmonary embolism with chest CT imaging, as they too will receive anticoagulation regardless.

Therefore, clinicians are encouraged to use diagnostic reasoning while practicing high-value care (including estimating pretest probability and measuring D-dimer when appropriate), ordering additional tests judiciously and only if indicated.

THROMBOEMBOLISM IS CONFIRMED—IS FURTHER TESTING WARRANTED?

Once acute venous thromboembolism is confirmed, key considerations include whether the event was provoked or unprovoked (ie, idiopathic) and whether the patient needs indefinite anticoagulation (eg, after 2 or more unprovoked events).

Was the event provoked or unprovoked?

Even in cases of unprovoked venous thromboembolism, no clear consensus exists as to which patients should be tested for thrombophilia. Experts do advocate, however, that it be done only in highly selected patients and that it be coordinated with the patient, family members, and an expert in this testing. Patients for whom further testing may be considered include those with venous thromboembolism in unusual sites (eg, the cavernous sinus), with warfarin-induced skin necrosis, or with recurrent pregnancy loss.

While screening for malignancy may seem prudent in the case of unexplained venous thromboembolism, the use of CT imaging for this purpose has been found to be of low yield. In one study,²⁴ it was not found to detect additional neoplasms, and it can lead to additional cost and no added benefit for patients.

The American Board of Internal Medicine’s Choosing Wisely campaign strongly recommends consultation with an expert in thrombophilia (eg, a hematologist) before testing.²⁵ Ordering multiple tests in bundles (hypercoagulability panels) is unlikely to alter management, could have a negative clinical impact on patients, and is generally not recommended.

The ‘4 Ps’ approach to testing

• Patient selection
• Pretest counseling
• Proper laboratory interpretation
• Provision of education and advice.

Importantly, testing should be reserved for patients in whom the pretest probability of the thrombophilic disease is moderate to high, such as testing for antiphospholipid antibody syndrome in patients with systemic lupus erythematosus or recurrent miscarriage.

Venous thromboembolism in a patient who is known to have a malignant disease does not typically warrant further thrombophilia testing, as the event was likely a sequela of the malignancy. The evaluation and management of venous thromboembolism with concurrent neoplasm is covered elsewhere.²¹

Thrombophilia testing should be approached the same regardless of whether the venous thromboembolism was diagnosed intentionally or incidentally. First, determine whether the thrombosis was provoked or unprovoked, then order additional tests only if indicated, as recommended. Alternative approaches such as forgoing anticoagulation (but performing serial imaging, if indicated) may be reasonable if the thrombus is deemed clinically irrelevant (eg, nonocclusive, asymptomatic, subsegmental pulmonary embolism in the absence of proximal deep vein thrombosis; isolated distal deep vein thrombosis).^25,27

It is still debatable whether the increasing incidence of asymptomatic pulmonary embolism due to enhanced sensitivity of noninvasive diagnostic imaging warrants a change in diagnostic approach.²⁸

FACTORS TO CONSIDER BEFORE THROMBOPHILIA TESTING

Important factors to consider before testing for thrombophilia are²⁹:

• How will the results affect the anticoagulation plan?
• How may the patient’s clinical status and medications influence the results?
• Has the patient expressed a desire to understand why venous thromboembolism occurred?
• Will the results have a potential impact on the patient’s family members?

How will the results of thrombophilia testing affect anticoagulation management?

Because the goal of any diagnostic test is to find out what type of care the patient needs, clinicians must determine whether knowledge of an underlying thrombophilia will alter the short-term or long-term anticoagulation therapy the patient is receiving for an acute venous thromboembolic event.

As most acute episodes of venous thromboembolism require an initial 3 months of anticoagulation (with the exception of some nonclinically relevant events such as isolated distal deep vein thrombosis without extension on reimaging), testing in the acute setting does not change the short-term management of anticoagulation. Many hospitals have advocated for outpatient-only thrombophilia testing (if testing does occur), as testing in the acute setting may render test results uninterpretable (see What factors can influence thrombophilia testing? below) and can inappropriately affect the long-term management of anticoagulation. We recommend against testing in the inpatient setting.

To determine the duration of anticoagulation, clinicians must balance the risk of recurrent venous thromboembolism and the risk of bleeding. If a patient is at significant risk of bleeding or does not tolerate anticoagulation, clinicians may consider stopping therapy instead of evaluating for thrombophilia. For patients with provoked venous thromboembolism, anticoagulation should generally be limited to 3 months, as the risk of recurrence does not outweigh the risk of bleeding with continued anticoagulation therapy.

Patients with unprovoked venous thromboembolism have a risk of recurrence twice as high as those with provoked venous thromboembolism and generally need a longer duration of anticoagulation.^30,31 Once a patient with an unprovoked venous thromboembolic event has completed the initial 3 months of anticoagulation, a formal risk-benefit evaluation should be performed to determine whether to continue it.

Up to 42% of patients with unprovoked venous thromboembolism may have 1 or more thrombotic disorders, and some clinicians believe that detecting an underlying thrombophilia will aid in decisions regarding duration of therapy.³² However, the risk of recurrent venous thromboembolism in these patients does not differ significantly from that in patients without an underlying thrombophilia.^33–35 As such, it has been suggested that the unprovoked character of the thrombotic event, rather than an underlying thrombophilia, determines the risk of future recurrence and should be used instead of testing to guide the duration of anticoagulation therapy.³²

For more information, see the 2016 ACCP guideline update on antithrombotic therapy for venous thromboembolism.²⁷

What factors can influence the results of thrombophilia testing?

For example, antithrombin is consumed during thrombus formation; therefore, antithrombin levels may be transiently suppressed in acute venous thromboembolism. Moreover, since antithrombin binds to unfractionated heparin, low-molecular-weight heparin, and fondaparinux and mediates their activity as anticoagulants, antithrombin levels may be decreased by heparin therapy.

Similarly, vitamin K antagonists (eg, warfarin) suppress protein C and S activity levels by inhibiting vitamin K epoxide reductase and may falsely indicate a protein C or S deficiency.

Direct oral anticoagulants can cause false-positive results on lupus anticoagulant assays (dilute Russell viper venom time, augmented partial thromboplastin time), raise protein C, protein S, and antithrombin activity levels, and normalize activated protein C resistance assays, leading to missed diagnoses.⁴¹

Since estrogen therapy and pregnancy lead to increases in C4b binding protein, resulting in decreased free protein S, these situations can result in clinicians falsely labeling patients as having congenital protein S deficiency when in fact the patient had a transient reduction in protein S levels.³³

Therefore, to optimize accuracy and interpretation of results, thrombophilia testing should ideally be performed when the patient:

• Is past the acute event and out of the hospital
• Is not pregnant
• Has received the required 3 months of anticoagulation and is off this therapy.

For warfarin, most recommendations say that testing should be performed after the patient has been off therapy for 2 to 6 weeks.⁴² Low-molecular-weight heparins and direct oral anticoagulants should be discontinued for at least 48 to 72 hours, or longer if the patient has kidney impairment, as these medications are renally eliminated.

Genetic tests such as factor V Leiden and prothrombin gene mutation are not affected by these factors and do not require repeat or confirmatory testing.

What if the patient or family wants to understand why an event occurred?

Some experts advocate thrombophilia testing of asymptomatic family members to identify carriers who may need prophylaxis against venous thromboembolism in high-risk situations such as pregnancy, oral contraceptive use, hospitalization, and surgery.²⁹ Asymptomatic family members of a first-degree relative with a history of venous thromboembolism have a 2 times higher risk of an index event.⁴³ Thus, it may be argued that these asymptomatic individuals should receive prophylactic measures in any high-risk situation, based on the family history itself rather than results of thrombophilia testing.

Occasionally, patients and family members want to know the cause of the thrombotic event and want to be tested. In these instances, pretest counseling for the patient and family about the potential implications of testing and shared decision-making between the provider and patient are of utmost importance.²⁹

What is the impact on family members if thrombophilia is diagnosed?

While positive test results can give patients some satisfaction, this knowledge may also cause unnecessary worry, as the patient knows he or she has a hematologic disorder and could possible die of venous thromboembolism.

Thrombophilia testing can have other adverse consequences. For example, while the Genetic Information Nondiscrimination Act of 2008 protects against denial of health insurance benefits based on genetic information, known carriers of thrombophilia may have trouble obtaining life or disability insurance.⁴⁴

Unfortunately, it is not uncommon for thrombophilia testing to be inappropriately performed, interpreted, or followed up. These suboptimal approaches can lead to unnecessary exposure to high-risk therapeutic anticoagulation, excessive durations of therapy, and labeling with an unconfirmed or incorrect diagnosis. Additionally, there are significant costs associated with thrombophilia testing, including the cost of the tests and anticoagulant medications and management of adverse events such as bleeding.

WHAT ARE THE ALTERNATIVES TO THROMBOPHILIA TESTING?

Because discovered thrombophilias (eg, factor V Leiden mutation, prothrombin gene mutation) have not consistently shown a strong correlation with increased recurrence of venous thromboembolism, alternative approaches are emerging to determine the duration of therapy for unprovoked events.

Clinical prediction tools based on patient characteristics and laboratory markers that are more consistently associated with recurrent venous thromboembolism (eg, male sex, persistently elevated D-dimer) have been developed to aid clinicians dealing with this challenging question. Several prediction tools are available:

The “Men Continue and HERDOO2” rule (HERDOO2 = hyperpigmentation, edema, or redness in either leg; D-dimer level ≥ 250 μg/L; obesity with body mass index ≥ 30 kg/m²; or older age, ≥ 65)⁴⁵

The DASH score (D-dimer, age, sex, and hormonal therapy)⁴⁶

The Vienna score,^47,48 at http://cemsiis.meduniwien.ac.at/en/kb/science-research/software/clinical-software/recurrent-vte/.

SUMMARY OF THROMBOPHILIA TESTING RECOMMENDATIONS

Test for thrombophilia only when…

• Discussing with a specialist (eg, hematologist) who has an understanding of thrombophilia
• Using the 4 Ps approach
• A patient requests testing to understand why a thrombotic event occurred, and the patient understands the implications of testing (ie, received counseling) for self and for family
• An expert deems identification of asymptomatic family members important for those who may be carriers of a detected thrombophilia
• The patient with a venous thromboembolic event has completed 3 months of anticoagulation and has been off anticoagulation for the appropriate length of time
• The results will change management.

Forgo thrombophilia testing when…

• A patient has a provoked venous thromboembolic event
• You do not intend to discontinue anticoagulation (ie, anticoagulation is indefinite)
• The patient is in the acute (eg, inpatient) setting
• The patient is on anticoagulants that may render test results uninterpretable
• The patient is pregnant or on oral contraceptives
• Use of alternative patient characteristics and laboratory markers to predict venous thromboembolism recurrence may be an option.

OPTIMIZING THE DIAGNOSIS

With the incidence of venous thromboembolism rapidly increasing, optimizing its diagnosis from both a financial and clinical perspective is becoming increasingly important. Clinicians should be familiar with the use of pretest probability scoring for venous thromboembolism, as well as which diagnostic tests are preferred if further workup is indicated. They should strive to minimize or avoid indiscriminate thrombophilia testing, which may lead to increased healthcare costs and patient exposure to potentially harmful anticoagulation.

Testing for thrombophilia should be based on whether a venous thromboembolic event was provoked or unprovoked. Patients with provoked venous thromboembolism or those receiving indefinite anticoagulation therapy should not be tested for thrombophilia. If testing is being considered in a patient with unprovoked venous thromboembolism, a specialist who is able to implement the 4 Ps approach should be consulted to ensure well-informed, shared decision-making with patients and family members.

When a patient presents with suspected venous thromboembolism, ie, deep vein thrombosis or pulmonary embolism, what diagnostic tests are needed to confirm the diagnosis? The clinical signs and symptoms of venous thromboembolism are nonspecific and often difficult to interpret. Therefore, it is essential for clinicians to use a standardized, structured approach to diagnosis that incorporates clinical findings and laboratory testing, as well as judicious use of diagnostic imaging. But while information is important, clinicians must also strive to avoid unnecessary testing, not only to decrease costs, but also to avoid potential harm.

If the diagnosis is confirmed, does the patient need testing for an underlying thrombophilic disorder? Such screening is often considered after a thromboembolic event occurs. However, a growing body of evidence indicates that the results of thrombophilia testing can be misinterpreted and potentially harmful.¹ We need to understand the utility of this testing as well as when and how it should be used. Patients and thrombosis specialists should be involved in deciding whether to perform these tests.

In this article, we provide practical information about how to diagnose venous thromboembolism, including strategies to optimize testing in suspected cases. We also offer guidance on how to decide whether further thrombophilia testing is warranted.

COMMON AND SERIOUS

Venous thromboembolism is a major cause of morbidity and death. Approximately 900,000 cases of pulmonary embolism and deep vein thrombosis occur in the United States each year, causing 60,000 to 300,000 deaths,² with the number of cases projected to double over the next 40 years.³

INITIAL APPROACH: PRETEST PROBABILITY

Given the morbidity and mortality associated with venous thromboembolism, prompt recognition and diagnosis are imperative. Clinical diagnosis alone is insufficient, with confirmed disease found in only 15% to 25% of patients suspected of having venous thromboembolism.^4–8 Therefore, the pretest probability should be coupled with objective testing.

The Wells score shows good discrimination in the outpatient and emergency department settings, but it has been invalidated in the inpatient setting, and thus it should not be used in inpatients.¹⁰

LABORATORY TESTS FOR SUSPECTED VENOUS THROMBOEMBOLISM

Employing an understanding of diagnostic testing is fundamental to identifying patients with venous thromboembolism.

D-dimer is a byproduct of fibrinolysis.

D-dimer testing has very high sensitivity for venous thromboembolism (> 90%) but low specificity (about 50%), and levels can be elevated in a variety of situations such as advanced age, acute inflammation, and cancer.¹⁵ The standard threshold is 500 μg/L, but because the D-dimer level increases with age, some clinicians advocate using an age-adjusted threshold for patients age 50 or older (age in years × 10 μg/L) to increase the diagnostic yield.¹⁶

Of the laboratory tests for D-dimer, the enzyme-linked immunosorbent assay has the highest sensitivity and highest negative predictive value (100%) and may be preferred over the other test methodologies.¹⁷

With its high sensitivity, D-dimer testing is clinically useful for ruling out venous thromboembolism, particularly when the pretest probability is low, but it lacks the specificity required for diagnosing and treating the disease if positive. Thus, it is not useful for ruling in venous thromboembolism. If the patient has a high pretest probability, we can omit D-dimer testing in favor of imaging studies.

Other laboratory tests such as arterial blood gas and brain natriuretic peptide levels have been proposed as markers of pulmonary embolism, but studies suggest they have limited utility in predicting the presence of disease.^18,19

DIAGNOSTIC TESTS FOR DEEP VEIN THROMBOSIS

Ultrasonography

If the pretest probability of deep vein thrombosis is high or a D-dimer test is found to be positive, the next step in evaluation is compression ultrasonography. 

While some guidelines recommend scanning only the proximal leg, many facilities in the United States scan the whole leg, which may reveal distal deep vein thrombosis.²⁰ The clinical significance of isolated distal deep vein thrombosis is unknown, and a selective anticoagulation approach may be used if this condition is discovered. The 2012 and 2016 American College of Chest Physicians (ACCP) guidelines on diagnosis and management of venous thromboembolism address this topic.^20,21

Deep vein thrombosis in the arm should be evaluated in the same manner as in the lower extremities.

Venography

Invasive and therefore no longer often used, venography is considered the gold standard for diagnosing deep vein thrombosis. Computed tomographic (CT) or magnetic resonance (MR) venography is most useful if the patient has aberrant anatomy such as a deformity of the leg, or in situations where the use of ultrasonography is difficult or unreliable, such as in the setting of severe obesity. CT or MR venography may be considered when looking for thrombosis in noncompressible veins of the thorax and abdomen (eg, the subclavian vein, iliac vein, and inferior vena cava) if ultrasonography is negative but clinical suspicion is high. Venous-phase CT angiography is particularly useful in diagnosing deep vein thrombosis in the inferior vena cava and iliac vein when deep vein thrombosis is clinically suspected but cannot be visualized on duplex ultrasonography.

Computed tomography

Imaging is warranted in patients who have a high pretest probability of pulmonary embolism, or in whom the D-dimer assay was positive but the pretest probability was low or moderate.

Once the gold standard, pulmonary angiography is no longer recommended for the initial diagnosis of pulmonary embolism because it is invasive, often unavailable, less sophisticated, and more expensive than noninvasive imaging techniques such as CT angiography. It is still used, however, in catheter-directed thrombolysis.

Thus, multiphasic CT angiography, as guided by pretest probability and the D-dimer level, is the imaging test of choice in the evaluation of pulmonary embolism. It can also offer insight into thrombotic burden and can reveal concurrent or alternative diagnoses (eg, pneumonia).

Ventilation-perfusion scanning

When CT angiography is unavailable or the patient should not be exposed to contrast medium (eg, due to concern for contrast-induced nephropathy or contrast allergy), ventilation-perfusion (V/Q) scanning remains an option for ruling out pulmonary embolism.²²

Anderson et al²³ compared CT angiography and V/Q scanning in a study in 1,417 patients considered likely to have acute pulmonary embolism. Rates of symptomatic pulmonary embolism during 3-month follow-up were similar in patients who initially had negative results on V/Q scanning compared with those who initially had negative results on CT angiography. However, this study used single-detector CT scanners for one-third of the patients. Therefore, the results may have been different if current technology had been used.

Limitations of V/Q scanning include length of time to perform (30–45 minutes), cost, inability to identify other causes of symptoms, and difficulty with interpretation  when other pulmonary pathology is present (eg, lung infiltrate). V/Q scanning is helpful when negative but is often reported based on probability (low, intermediate, or high) and may not provide adequate guidance. Therefore, CT angiography should be used whenever possible for diagnosing pulmonary embolism.

Other tests for pulmonary embolism

Electrocardiography, transthoracic echocardiography, and chest radiography may aid in the search for alternative diagnoses and assess the degree of right heart strain as a sequela of pulmonary embolism, but they do not confirm the diagnosis.

ORDER IMAGING ONLY IF NEEDED

Diagnostic imaging can be optimized by avoiding unnecessary tests that carry both costs and clinical risks.

Most patients in whom acute pulmonary embolism is discovered will not need testing for deep vein thrombosis, as they will receive anticoagulation regardless. Similarly, many patients with acute symptomatic deep vein thrombosis do not need testing for pulmonary embolism with chest CT imaging, as they too will receive anticoagulation regardless.

Therefore, clinicians are encouraged to use diagnostic reasoning while practicing high-value care (including estimating pretest probability and measuring D-dimer when appropriate), ordering additional tests judiciously and only if indicated.

THROMBOEMBOLISM IS CONFIRMED—IS FURTHER TESTING WARRANTED?

Once acute venous thromboembolism is confirmed, key considerations include whether the event was provoked or unprovoked (ie, idiopathic) and whether the patient needs indefinite anticoagulation (eg, after 2 or more unprovoked events).

Was the event provoked or unprovoked?

Even in cases of unprovoked venous thromboembolism, no clear consensus exists as to which patients should be tested for thrombophilia. Experts do advocate, however, that it be done only in highly selected patients and that it be coordinated with the patient, family members, and an expert in this testing. Patients for whom further testing may be considered include those with venous thromboembolism in unusual sites (eg, the cavernous sinus), with warfarin-induced skin necrosis, or with recurrent pregnancy loss.

While screening for malignancy may seem prudent in the case of unexplained venous thromboembolism, the use of CT imaging for this purpose has been found to be of low yield. In one study,²⁴ it was not found to detect additional neoplasms, and it can lead to additional cost and no added benefit for patients.

The American Board of Internal Medicine’s Choosing Wisely campaign strongly recommends consultation with an expert in thrombophilia (eg, a hematologist) before testing.²⁵ Ordering multiple tests in bundles (hypercoagulability panels) is unlikely to alter management, could have a negative clinical impact on patients, and is generally not recommended.

The ‘4 Ps’ approach to testing

• Patient selection
• Pretest counseling
• Proper laboratory interpretation
• Provision of education and advice.

Importantly, testing should be reserved for patients in whom the pretest probability of the thrombophilic disease is moderate to high, such as testing for antiphospholipid antibody syndrome in patients with systemic lupus erythematosus or recurrent miscarriage.

Venous thromboembolism in a patient who is known to have a malignant disease does not typically warrant further thrombophilia testing, as the event was likely a sequela of the malignancy. The evaluation and management of venous thromboembolism with concurrent neoplasm is covered elsewhere.²¹

Thrombophilia testing should be approached the same regardless of whether the venous thromboembolism was diagnosed intentionally or incidentally. First, determine whether the thrombosis was provoked or unprovoked, then order additional tests only if indicated, as recommended. Alternative approaches such as forgoing anticoagulation (but performing serial imaging, if indicated) may be reasonable if the thrombus is deemed clinically irrelevant (eg, nonocclusive, asymptomatic, subsegmental pulmonary embolism in the absence of proximal deep vein thrombosis; isolated distal deep vein thrombosis).^25,27

It is still debatable whether the increasing incidence of asymptomatic pulmonary embolism due to enhanced sensitivity of noninvasive diagnostic imaging warrants a change in diagnostic approach.²⁸

FACTORS TO CONSIDER BEFORE THROMBOPHILIA TESTING

Important factors to consider before testing for thrombophilia are²⁹:

• How will the results affect the anticoagulation plan?
• How may the patient’s clinical status and medications influence the results?
• Has the patient expressed a desire to understand why venous thromboembolism occurred?
• Will the results have a potential impact on the patient’s family members?

How will the results of thrombophilia testing affect anticoagulation management?

Because the goal of any diagnostic test is to find out what type of care the patient needs, clinicians must determine whether knowledge of an underlying thrombophilia will alter the short-term or long-term anticoagulation therapy the patient is receiving for an acute venous thromboembolic event.

As most acute episodes of venous thromboembolism require an initial 3 months of anticoagulation (with the exception of some nonclinically relevant events such as isolated distal deep vein thrombosis without extension on reimaging), testing in the acute setting does not change the short-term management of anticoagulation. Many hospitals have advocated for outpatient-only thrombophilia testing (if testing does occur), as testing in the acute setting may render test results uninterpretable (see What factors can influence thrombophilia testing? below) and can inappropriately affect the long-term management of anticoagulation. We recommend against testing in the inpatient setting.

To determine the duration of anticoagulation, clinicians must balance the risk of recurrent venous thromboembolism and the risk of bleeding. If a patient is at significant risk of bleeding or does not tolerate anticoagulation, clinicians may consider stopping therapy instead of evaluating for thrombophilia. For patients with provoked venous thromboembolism, anticoagulation should generally be limited to 3 months, as the risk of recurrence does not outweigh the risk of bleeding with continued anticoagulation therapy.

Patients with unprovoked venous thromboembolism have a risk of recurrence twice as high as those with provoked venous thromboembolism and generally need a longer duration of anticoagulation.^30,31 Once a patient with an unprovoked venous thromboembolic event has completed the initial 3 months of anticoagulation, a formal risk-benefit evaluation should be performed to determine whether to continue it.

Up to 42% of patients with unprovoked venous thromboembolism may have 1 or more thrombotic disorders, and some clinicians believe that detecting an underlying thrombophilia will aid in decisions regarding duration of therapy.³² However, the risk of recurrent venous thromboembolism in these patients does not differ significantly from that in patients without an underlying thrombophilia.^33–35 As such, it has been suggested that the unprovoked character of the thrombotic event, rather than an underlying thrombophilia, determines the risk of future recurrence and should be used instead of testing to guide the duration of anticoagulation therapy.³²

For more information, see the 2016 ACCP guideline update on antithrombotic therapy for venous thromboembolism.²⁷

What factors can influence the results of thrombophilia testing?

For example, antithrombin is consumed during thrombus formation; therefore, antithrombin levels may be transiently suppressed in acute venous thromboembolism. Moreover, since antithrombin binds to unfractionated heparin, low-molecular-weight heparin, and fondaparinux and mediates their activity as anticoagulants, antithrombin levels may be decreased by heparin therapy.

Similarly, vitamin K antagonists (eg, warfarin) suppress protein C and S activity levels by inhibiting vitamin K epoxide reductase and may falsely indicate a protein C or S deficiency.

Direct oral anticoagulants can cause false-positive results on lupus anticoagulant assays (dilute Russell viper venom time, augmented partial thromboplastin time), raise protein C, protein S, and antithrombin activity levels, and normalize activated protein C resistance assays, leading to missed diagnoses.⁴¹

Since estrogen therapy and pregnancy lead to increases in C4b binding protein, resulting in decreased free protein S, these situations can result in clinicians falsely labeling patients as having congenital protein S deficiency when in fact the patient had a transient reduction in protein S levels.³³

Therefore, to optimize accuracy and interpretation of results, thrombophilia testing should ideally be performed when the patient:

• Is past the acute event and out of the hospital
• Is not pregnant
• Has received the required 3 months of anticoagulation and is off this therapy.

For warfarin, most recommendations say that testing should be performed after the patient has been off therapy for 2 to 6 weeks.⁴² Low-molecular-weight heparins and direct oral anticoagulants should be discontinued for at least 48 to 72 hours, or longer if the patient has kidney impairment, as these medications are renally eliminated.

Genetic tests such as factor V Leiden and prothrombin gene mutation are not affected by these factors and do not require repeat or confirmatory testing.

What if the patient or family wants to understand why an event occurred?

Some experts advocate thrombophilia testing of asymptomatic family members to identify carriers who may need prophylaxis against venous thromboembolism in high-risk situations such as pregnancy, oral contraceptive use, hospitalization, and surgery.²⁹ Asymptomatic family members of a first-degree relative with a history of venous thromboembolism have a 2 times higher risk of an index event.⁴³ Thus, it may be argued that these asymptomatic individuals should receive prophylactic measures in any high-risk situation, based on the family history itself rather than results of thrombophilia testing.

Occasionally, patients and family members want to know the cause of the thrombotic event and want to be tested. In these instances, pretest counseling for the patient and family about the potential implications of testing and shared decision-making between the provider and patient are of utmost importance.²⁹

What is the impact on family members if thrombophilia is diagnosed?

While positive test results can give patients some satisfaction, this knowledge may also cause unnecessary worry, as the patient knows he or she has a hematologic disorder and could possible die of venous thromboembolism.

Thrombophilia testing can have other adverse consequences. For example, while the Genetic Information Nondiscrimination Act of 2008 protects against denial of health insurance benefits based on genetic information, known carriers of thrombophilia may have trouble obtaining life or disability insurance.⁴⁴

Unfortunately, it is not uncommon for thrombophilia testing to be inappropriately performed, interpreted, or followed up. These suboptimal approaches can lead to unnecessary exposure to high-risk therapeutic anticoagulation, excessive durations of therapy, and labeling with an unconfirmed or incorrect diagnosis. Additionally, there are significant costs associated with thrombophilia testing, including the cost of the tests and anticoagulant medications and management of adverse events such as bleeding.

WHAT ARE THE ALTERNATIVES TO THROMBOPHILIA TESTING?

Because discovered thrombophilias (eg, factor V Leiden mutation, prothrombin gene mutation) have not consistently shown a strong correlation with increased recurrence of venous thromboembolism, alternative approaches are emerging to determine the duration of therapy for unprovoked events.

Clinical prediction tools based on patient characteristics and laboratory markers that are more consistently associated with recurrent venous thromboembolism (eg, male sex, persistently elevated D-dimer) have been developed to aid clinicians dealing with this challenging question. Several prediction tools are available:

The “Men Continue and HERDOO2” rule (HERDOO2 = hyperpigmentation, edema, or redness in either leg; D-dimer level ≥ 250 μg/L; obesity with body mass index ≥ 30 kg/m²; or older age, ≥ 65)⁴⁵

The DASH score (D-dimer, age, sex, and hormonal therapy)⁴⁶

The Vienna score,^47,48 at http://cemsiis.meduniwien.ac.at/en/kb/science-research/software/clinical-software/recurrent-vte/.

SUMMARY OF THROMBOPHILIA TESTING RECOMMENDATIONS

Test for thrombophilia only when…

• Discussing with a specialist (eg, hematologist) who has an understanding of thrombophilia
• Using the 4 Ps approach
• A patient requests testing to understand why a thrombotic event occurred, and the patient understands the implications of testing (ie, received counseling) for self and for family
• An expert deems identification of asymptomatic family members important for those who may be carriers of a detected thrombophilia
• The patient with a venous thromboembolic event has completed 3 months of anticoagulation and has been off anticoagulation for the appropriate length of time
• The results will change management.

Forgo thrombophilia testing when…

• A patient has a provoked venous thromboembolic event
• You do not intend to discontinue anticoagulation (ie, anticoagulation is indefinite)
• The patient is in the acute (eg, inpatient) setting
• The patient is on anticoagulants that may render test results uninterpretable
• The patient is pregnant or on oral contraceptives
• Use of alternative patient characteristics and laboratory markers to predict venous thromboembolism recurrence may be an option.

OPTIMIZING THE DIAGNOSIS

With the incidence of venous thromboembolism rapidly increasing, optimizing its diagnosis from both a financial and clinical perspective is becoming increasingly important. Clinicians should be familiar with the use of pretest probability scoring for venous thromboembolism, as well as which diagnostic tests are preferred if further workup is indicated. They should strive to minimize or avoid indiscriminate thrombophilia testing, which may lead to increased healthcare costs and patient exposure to potentially harmful anticoagulation.

Testing for thrombophilia should be based on whether a venous thromboembolic event was provoked or unprovoked. Patients with provoked venous thromboembolism or those receiving indefinite anticoagulation therapy should not be tested for thrombophilia. If testing is being considered in a patient with unprovoked venous thromboembolism, a specialist who is able to implement the 4 Ps approach should be consulted to ensure well-informed, shared decision-making with patients and family members.

See related editorial

Results of laboratory testing included a positive reactive syphilis immunoglobulin G (IgG) enzyme immunoassay and a positive rapid plasma reagin (RPR) test (titer 1:256). Human immunodeficiency virus (HIV) testing was negative, and serologic testing demonstrated prior immunization to hepatitis B virus. Given the clinical presentation and laboratory findings, secondary syphilis was considered the most probable diagnosis.

The patient was treated with benzathine penicillin G 2.4 million units intramuscularly.

SYPHILIS: A REEMERGING CONDITION

Epidemiology

The rate of reported primary and secondary syphilis cases in the United States has risen since 2001.¹ Most cases occur in men who have sex with men.¹ Additional risk factors include condomless intercourse and drug use.²

Signs and symptoms of the 3 stages

Primary syphilis begins 2 to 3 weeks after inoculation of a mucosal surface.³ This stage is marked by one or more painless chancres and, in some cases, local nontender lymphadenopathy.^3,4 Secondary syphilis presents 4 to 8 weeks later with systemic symptoms including rash, classically involving the palms or soles, lymphadenopathy, myalgia, fever, and weight loss.^2,3 Untreated primary and secondary syphilis may progress to latent or asymptomatic disease.⁵

Tertiary syphilis, defined by the US Centers for Disease Control and Prevention (CDC) as gummas or cardiovascular syphilis, occurs 15 to 30 years after an untreated exposure.^4,6 Neurosyphilis can present at any stage of the disease.⁶

Diagnosis

The diagnosis of syphilis involves a nontreponemal test such as RPR or Venereal Disease Research Laboratory (VDRL) to screen for disease, followed by a treponemal antibody test such as fluorescent treponemal antibody-absorption, Treponema pallidum particle agglutination assay, or syphilis IgG to confirm the diagnosis.⁵ There is no screening test for tertiary disease in patients previously diagnosed with primary or secondary syphilis, but a cerebrospinal fluid (CSF) examination is recommended if neurologic or ocular manifestations are present.⁶

Treatment

Treatment of primary, secondary, and early latent syphilis is a single dose of 2.4 million units of benzathine penicillin G given intramuscularly.⁷ The treatment of late latent and tertiary syphilis is less well defined by the current literature but generally includes penicillin.⁷

Patients with primary and secondary syphilis undergo serologic and clinical evaluation at 6 and 12 months to be assessed for treatment failure or reinfection.⁶ Patients with latent disease require serologic follow-up at 6, 12, and 24 months.⁶ Additionally, CSF analysis should be done if baseline high titers do not fall within 12 to 24 months of treatment or if symptoms suggest syphilis.⁶ Patients with neurosyphilis often require CSF evaluation every 6 months.⁶ Follow-up for patients with tertiary syphilis is less well defined.

Patients coinfected with HIV have special needs and considerations, as outlined in the CDC’s 2015 Sexually Transmitted Diseases Treatment Guidelines.⁶

Sexual contacts of patients with syphilis deserve evaluation. Exposure within 90 days of a patient’s diagnosis with primary, secondary, or latent disease requires treatment regardless of the results of serologic testing.⁶ Persons exposed more than 90 days before diagnosis may undergo serologic testing; however, if results are not immediately available or follow-up is unlikely, the individual should be treated for early syphilis.⁶ If serologic testing results are negative, no treatment is required.⁶

See related editorial

Results of laboratory testing included a positive reactive syphilis immunoglobulin G (IgG) enzyme immunoassay and a positive rapid plasma reagin (RPR) test (titer 1:256). Human immunodeficiency virus (HIV) testing was negative, and serologic testing demonstrated prior immunization to hepatitis B virus. Given the clinical presentation and laboratory findings, secondary syphilis was considered the most probable diagnosis.

The patient was treated with benzathine penicillin G 2.4 million units intramuscularly.

SYPHILIS: A REEMERGING CONDITION

Epidemiology

The rate of reported primary and secondary syphilis cases in the United States has risen since 2001.¹ Most cases occur in men who have sex with men.¹ Additional risk factors include condomless intercourse and drug use.²

Signs and symptoms of the 3 stages

Primary syphilis begins 2 to 3 weeks after inoculation of a mucosal surface.³ This stage is marked by one or more painless chancres and, in some cases, local nontender lymphadenopathy.^3,4 Secondary syphilis presents 4 to 8 weeks later with systemic symptoms including rash, classically involving the palms or soles, lymphadenopathy, myalgia, fever, and weight loss.^2,3 Untreated primary and secondary syphilis may progress to latent or asymptomatic disease.⁵

Tertiary syphilis, defined by the US Centers for Disease Control and Prevention (CDC) as gummas or cardiovascular syphilis, occurs 15 to 30 years after an untreated exposure.^4,6 Neurosyphilis can present at any stage of the disease.⁶

Diagnosis

The diagnosis of syphilis involves a nontreponemal test such as RPR or Venereal Disease Research Laboratory (VDRL) to screen for disease, followed by a treponemal antibody test such as fluorescent treponemal antibody-absorption, Treponema pallidum particle agglutination assay, or syphilis IgG to confirm the diagnosis.⁵ There is no screening test for tertiary disease in patients previously diagnosed with primary or secondary syphilis, but a cerebrospinal fluid (CSF) examination is recommended if neurologic or ocular manifestations are present.⁶

Treatment

Treatment of primary, secondary, and early latent syphilis is a single dose of 2.4 million units of benzathine penicillin G given intramuscularly.⁷ The treatment of late latent and tertiary syphilis is less well defined by the current literature but generally includes penicillin.⁷

Patients with primary and secondary syphilis undergo serologic and clinical evaluation at 6 and 12 months to be assessed for treatment failure or reinfection.⁶ Patients with latent disease require serologic follow-up at 6, 12, and 24 months.⁶ Additionally, CSF analysis should be done if baseline high titers do not fall within 12 to 24 months of treatment or if symptoms suggest syphilis.⁶ Patients with neurosyphilis often require CSF evaluation every 6 months.⁶ Follow-up for patients with tertiary syphilis is less well defined.

Patients coinfected with HIV have special needs and considerations, as outlined in the CDC’s 2015 Sexually Transmitted Diseases Treatment Guidelines.⁶

Sexual contacts of patients with syphilis deserve evaluation. Exposure within 90 days of a patient’s diagnosis with primary, secondary, or latent disease requires treatment regardless of the results of serologic testing.⁶ Persons exposed more than 90 days before diagnosis may undergo serologic testing; however, if results are not immediately available or follow-up is unlikely, the individual should be treated for early syphilis.⁶ If serologic testing results are negative, no treatment is required.⁶

See related editorial

Results of laboratory testing included a positive reactive syphilis immunoglobulin G (IgG) enzyme immunoassay and a positive rapid plasma reagin (RPR) test (titer 1:256). Human immunodeficiency virus (HIV) testing was negative, and serologic testing demonstrated prior immunization to hepatitis B virus. Given the clinical presentation and laboratory findings, secondary syphilis was considered the most probable diagnosis.

The patient was treated with benzathine penicillin G 2.4 million units intramuscularly.

SYPHILIS: A REEMERGING CONDITION

Epidemiology

The rate of reported primary and secondary syphilis cases in the United States has risen since 2001.¹ Most cases occur in men who have sex with men.¹ Additional risk factors include condomless intercourse and drug use.²

Signs and symptoms of the 3 stages

Primary syphilis begins 2 to 3 weeks after inoculation of a mucosal surface.³ This stage is marked by one or more painless chancres and, in some cases, local nontender lymphadenopathy.^3,4 Secondary syphilis presents 4 to 8 weeks later with systemic symptoms including rash, classically involving the palms or soles, lymphadenopathy, myalgia, fever, and weight loss.^2,3 Untreated primary and secondary syphilis may progress to latent or asymptomatic disease.⁵

Tertiary syphilis, defined by the US Centers for Disease Control and Prevention (CDC) as gummas or cardiovascular syphilis, occurs 15 to 30 years after an untreated exposure.^4,6 Neurosyphilis can present at any stage of the disease.⁶

Diagnosis

The diagnosis of syphilis involves a nontreponemal test such as RPR or Venereal Disease Research Laboratory (VDRL) to screen for disease, followed by a treponemal antibody test such as fluorescent treponemal antibody-absorption, Treponema pallidum particle agglutination assay, or syphilis IgG to confirm the diagnosis.⁵ There is no screening test for tertiary disease in patients previously diagnosed with primary or secondary syphilis, but a cerebrospinal fluid (CSF) examination is recommended if neurologic or ocular manifestations are present.⁶

Treatment

Treatment of primary, secondary, and early latent syphilis is a single dose of 2.4 million units of benzathine penicillin G given intramuscularly.⁷ The treatment of late latent and tertiary syphilis is less well defined by the current literature but generally includes penicillin.⁷

Patients with primary and secondary syphilis undergo serologic and clinical evaluation at 6 and 12 months to be assessed for treatment failure or reinfection.⁶ Patients with latent disease require serologic follow-up at 6, 12, and 24 months.⁶ Additionally, CSF analysis should be done if baseline high titers do not fall within 12 to 24 months of treatment or if symptoms suggest syphilis.⁶ Patients with neurosyphilis often require CSF evaluation every 6 months.⁶ Follow-up for patients with tertiary syphilis is less well defined.

Patients coinfected with HIV have special needs and considerations, as outlined in the CDC’s 2015 Sexually Transmitted Diseases Treatment Guidelines.⁶

Sexual contacts of patients with syphilis deserve evaluation. Exposure within 90 days of a patient’s diagnosis with primary, secondary, or latent disease requires treatment regardless of the results of serologic testing.⁶ Persons exposed more than 90 days before diagnosis may undergo serologic testing; however, if results are not immediately available or follow-up is unlikely, the individual should be treated for early syphilis.⁶ If serologic testing results are negative, no treatment is required.⁶

According to a report from the US Centers for Disease Control and Prevention (CDC) on the incidence of sexually transmitted diseases (STDs), “Total combined cases of chlamydia, gonorrhea, and syphilis reported in 2015 reached the highest number ever”¹ since the CDC was founded in July 1946.

See related article

Nearly 24,000 cases of primary and secondary syphilis were reported in 2015, a 19% increase from the previous year. And Dr. Jonathan Mermin, director of the CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, reported, “We have reached a decisive moment for the nation. STD rates are rising, and many of the country’s systems for preventing STDs have eroded. We must mobilize, rebuild, and expand services—or the human and economic burden will continue to grow.”¹

Dr. Mermin stressed the need to rebuild services because, “In recent years more than half of state and local STD programs have experienced budget cuts, resulting in more than 20 health department STD clinic closures in one year alone. Fewer clinics mean reduced access to STD testing and treatment for those who need these services.”¹

The CDC also reports that STD treatment costs the US healthcare system nearly $16 billion each year.

The CDC has identified several players whose engagement is necessary to stem the tide of this epidemic:

• Providers must make STD screening a standard part of medical care, especially in pregnant women, and integrate STD prevention and treatment into prenatal care and other routine visits.
• People need to talk openly about STDs, get tested regularly, and reduce risk by using condoms or practicing mutual monogamy if sexually active.
• Parents and providers need to offer young people safe, effective ways to get information and services.
• State and local health departments should continue to direct resources to people hardest hit by the STD epidemic and work with community partners to maximize their impact.¹

STD CAMPAIGNS 100 YEARS AGO

This message sounds familiar. Let’s go back 100 years to World War I. The book No Magic Bullet by Allan M. Brandt² provides fascinating details about this period in America’s battle against venereal diseases. While the book is well worth reading in its entirety, I will attempt here to summarize the pertinent facts.

In the late 1910s, antivenereal campaigns were in full swing, with publicly shown movies such as “Fit to Fight” to train soldiers about STD symptoms and prevention to keep them physically healthy for fighting in the war. Similar information was widely available stateside for both men and women in open, matter-of-fact formats to encourage STD prevention.

After the war ended, the national sentiment became split between sexual revolution and social moralism. “Social hygienists” blamed the widespread increase in promiscuity on the newly introduced sexually explicit philosophy of Sigmund Freud, the widespread availability of automobiles (ie, a mobile, private, backseat location for sex), popular “vulgar” dances, and social feminism, among many others. The sexual revolution clearly led to an increased risk of STDs. But the antivenereal campaigns that had been appropriate in wartime came to be considered amoral and unfit for public consumption, and a period of silence about venereal diseases ensued.

By the 1930s, the situation had worsened:

• Approximately 1 out of every 10 Americans suffered from syphilis.
• Each year, Americans contracted almost half a million new syphilis infections (twice as many cases as tuberculosis, and 100 times as many cases as polio).
• 18% of all deaths from organic heart disease could be attributed to syphilis.
• Up to 20% of all mental institution inmates suffered from tertiary syphilis.
• 60,000 children were born each year with congenital syphilis.²

Although penicillin was still a decade or more away from discovery, syphilis could be treated, though likely not cured, with arsenic compounds. A course of treatment from a private physician, however, could cost from $300 to $1,000. Many patients who could not pay these exorbitant prices turned to public clinics for help. However, funding for the Venereal Disease Division of the Public Health Service, originally $4 million in 1920, was cut to less than $60,000 by 1926.² Some hospitals refused to admit patients with syphilis and other venereal diseases, deeming them “morally tainted and less deserving of care.”²

Things couldn’t get much worse.

Dr. Thomas Parran was the New York State health commissioner in 1930, at the start of the Great Depression. Realizing that arguments for moral responsibility to prevent and treat venereal diseases were not effective, Dr. Parran and other public health officials turned to financial arguments. Among the most persuasive arguments, “More than $15 million was spent annually for the ambulatory care of venereal patients…Experts argued that syphilis costs taxpayers between $40 and $50 million each year for the institutional care of the insane, paralyzed, and blind.”² The American Medical Association calculated that “8 to 10 million workers lost 21 million working days each year at an average of $4 a day as a result of infection with these conditions.”² The cost was estimated at more than $100,000,000 annually.²

But the general public was not a part of the larger conversation regarding treatment and prevention of syphilis, thanks to the social hygienists. In November 1934, Dr. Parran was scheduled to give a radio broadcast on future goals for public health in New York. Notified that he would not be able to mention syphilis or gonorrhea by name, he refused to give the speech. Dr. Parran went on to lead the charge to reduce the moral cloud that blocked the ability to address syphilis openly and scientifically. With his extensive experience in public health, he proposed plans that had been effective in controlling other infectious diseases as measures to control the spread of syphilis. He outlined the following:

• Identify cases of syphilis. Offer free diagnostic centers where individuals could obtain confidential blood tests.
• Offer prompt therapy for identified cases.
• Identify, locate, and test all contacts of infected patients, and treat them if they are infected too.
• Make blood testing mandatory before marriage and early in all pregnancies.
• Educate the public concerning syphilis.²

Do these approaches sound familiar?

Appointed US Surgeon General in 1936 by President Franklin Delano Roosevelt, Dr. Parran published “The next great plague to go,”³ an article focusing on the medical approach to treating syphilis and other venereal diseases, while refusing to address the moral and social issues.³ This was widely acclaimed by the public and the press. Two years after he was blocked from mentioning syphilis and gonorrhea on the radio, he was pictured on the cover of Time magazine for his groundbreaking work.

With the advent of penicillin, syphilis became not only treatable but curable. Over the next decades, the number of patients infected with syphilis and the morbidity it caused continually declined until the 1990s, when there were even whispers of eradication in the United States. This likely came in part due to the AIDS epidemic and the increased public discourse on safe sex.

However, the 1990s saw a new rise in cases of syphilis. This clearly could not be blamed on the social hygienists; rather, it was likely due to apathy and a decline in public health spending. We are now in a period of rapid rise in STDs.

We have the benefit of antibiotics. We have the benefit of hindsight. What we need is to heed the call to arms of Dr. Mermin, to be inspired by the wisdom of Dr. Parran, and to act. Identify the case of syphilis, offer treatment, educate the public. Drs. Coleman, Fiahlo, and Brateanu have accomplished all of these in their article in this issue of the Journal.⁴

According to a report from the US Centers for Disease Control and Prevention (CDC) on the incidence of sexually transmitted diseases (STDs), “Total combined cases of chlamydia, gonorrhea, and syphilis reported in 2015 reached the highest number ever”¹ since the CDC was founded in July 1946.

See related article

Nearly 24,000 cases of primary and secondary syphilis were reported in 2015, a 19% increase from the previous year. And Dr. Jonathan Mermin, director of the CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, reported, “We have reached a decisive moment for the nation. STD rates are rising, and many of the country’s systems for preventing STDs have eroded. We must mobilize, rebuild, and expand services—or the human and economic burden will continue to grow.”¹

Dr. Mermin stressed the need to rebuild services because, “In recent years more than half of state and local STD programs have experienced budget cuts, resulting in more than 20 health department STD clinic closures in one year alone. Fewer clinics mean reduced access to STD testing and treatment for those who need these services.”¹

The CDC also reports that STD treatment costs the US healthcare system nearly $16 billion each year.

The CDC has identified several players whose engagement is necessary to stem the tide of this epidemic:

• Providers must make STD screening a standard part of medical care, especially in pregnant women, and integrate STD prevention and treatment into prenatal care and other routine visits.
• People need to talk openly about STDs, get tested regularly, and reduce risk by using condoms or practicing mutual monogamy if sexually active.
• Parents and providers need to offer young people safe, effective ways to get information and services.
• State and local health departments should continue to direct resources to people hardest hit by the STD epidemic and work with community partners to maximize their impact.¹

STD CAMPAIGNS 100 YEARS AGO

This message sounds familiar. Let’s go back 100 years to World War I. The book No Magic Bullet by Allan M. Brandt² provides fascinating details about this period in America’s battle against venereal diseases. While the book is well worth reading in its entirety, I will attempt here to summarize the pertinent facts.

In the late 1910s, antivenereal campaigns were in full swing, with publicly shown movies such as “Fit to Fight” to train soldiers about STD symptoms and prevention to keep them physically healthy for fighting in the war. Similar information was widely available stateside for both men and women in open, matter-of-fact formats to encourage STD prevention.

After the war ended, the national sentiment became split between sexual revolution and social moralism. “Social hygienists” blamed the widespread increase in promiscuity on the newly introduced sexually explicit philosophy of Sigmund Freud, the widespread availability of automobiles (ie, a mobile, private, backseat location for sex), popular “vulgar” dances, and social feminism, among many others. The sexual revolution clearly led to an increased risk of STDs. But the antivenereal campaigns that had been appropriate in wartime came to be considered amoral and unfit for public consumption, and a period of silence about venereal diseases ensued.

By the 1930s, the situation had worsened:

• Approximately 1 out of every 10 Americans suffered from syphilis.
• Each year, Americans contracted almost half a million new syphilis infections (twice as many cases as tuberculosis, and 100 times as many cases as polio).
• 18% of all deaths from organic heart disease could be attributed to syphilis.
• Up to 20% of all mental institution inmates suffered from tertiary syphilis.
• 60,000 children were born each year with congenital syphilis.²

Although penicillin was still a decade or more away from discovery, syphilis could be treated, though likely not cured, with arsenic compounds. A course of treatment from a private physician, however, could cost from $300 to $1,000. Many patients who could not pay these exorbitant prices turned to public clinics for help. However, funding for the Venereal Disease Division of the Public Health Service, originally $4 million in 1920, was cut to less than $60,000 by 1926.² Some hospitals refused to admit patients with syphilis and other venereal diseases, deeming them “morally tainted and less deserving of care.”²

Things couldn’t get much worse.

Dr. Thomas Parran was the New York State health commissioner in 1930, at the start of the Great Depression. Realizing that arguments for moral responsibility to prevent and treat venereal diseases were not effective, Dr. Parran and other public health officials turned to financial arguments. Among the most persuasive arguments, “More than $15 million was spent annually for the ambulatory care of venereal patients…Experts argued that syphilis costs taxpayers between $40 and $50 million each year for the institutional care of the insane, paralyzed, and blind.”² The American Medical Association calculated that “8 to 10 million workers lost 21 million working days each year at an average of $4 a day as a result of infection with these conditions.”² The cost was estimated at more than $100,000,000 annually.²

But the general public was not a part of the larger conversation regarding treatment and prevention of syphilis, thanks to the social hygienists. In November 1934, Dr. Parran was scheduled to give a radio broadcast on future goals for public health in New York. Notified that he would not be able to mention syphilis or gonorrhea by name, he refused to give the speech. Dr. Parran went on to lead the charge to reduce the moral cloud that blocked the ability to address syphilis openly and scientifically. With his extensive experience in public health, he proposed plans that had been effective in controlling other infectious diseases as measures to control the spread of syphilis. He outlined the following:

• Identify cases of syphilis. Offer free diagnostic centers where individuals could obtain confidential blood tests.
• Offer prompt therapy for identified cases.
• Identify, locate, and test all contacts of infected patients, and treat them if they are infected too.
• Make blood testing mandatory before marriage and early in all pregnancies.
• Educate the public concerning syphilis.²

Do these approaches sound familiar?

Appointed US Surgeon General in 1936 by President Franklin Delano Roosevelt, Dr. Parran published “The next great plague to go,”³ an article focusing on the medical approach to treating syphilis and other venereal diseases, while refusing to address the moral and social issues.³ This was widely acclaimed by the public and the press. Two years after he was blocked from mentioning syphilis and gonorrhea on the radio, he was pictured on the cover of Time magazine for his groundbreaking work.

With the advent of penicillin, syphilis became not only treatable but curable. Over the next decades, the number of patients infected with syphilis and the morbidity it caused continually declined until the 1990s, when there were even whispers of eradication in the United States. This likely came in part due to the AIDS epidemic and the increased public discourse on safe sex.

However, the 1990s saw a new rise in cases of syphilis. This clearly could not be blamed on the social hygienists; rather, it was likely due to apathy and a decline in public health spending. We are now in a period of rapid rise in STDs.

We have the benefit of antibiotics. We have the benefit of hindsight. What we need is to heed the call to arms of Dr. Mermin, to be inspired by the wisdom of Dr. Parran, and to act. Identify the case of syphilis, offer treatment, educate the public. Drs. Coleman, Fiahlo, and Brateanu have accomplished all of these in their article in this issue of the Journal.⁴

According to a report from the US Centers for Disease Control and Prevention (CDC) on the incidence of sexually transmitted diseases (STDs), “Total combined cases of chlamydia, gonorrhea, and syphilis reported in 2015 reached the highest number ever”¹ since the CDC was founded in July 1946.

See related article

Nearly 24,000 cases of primary and secondary syphilis were reported in 2015, a 19% increase from the previous year. And Dr. Jonathan Mermin, director of the CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, reported, “We have reached a decisive moment for the nation. STD rates are rising, and many of the country’s systems for preventing STDs have eroded. We must mobilize, rebuild, and expand services—or the human and economic burden will continue to grow.”¹

Dr. Mermin stressed the need to rebuild services because, “In recent years more than half of state and local STD programs have experienced budget cuts, resulting in more than 20 health department STD clinic closures in one year alone. Fewer clinics mean reduced access to STD testing and treatment for those who need these services.”¹

The CDC also reports that STD treatment costs the US healthcare system nearly $16 billion each year.

The CDC has identified several players whose engagement is necessary to stem the tide of this epidemic:

• Providers must make STD screening a standard part of medical care, especially in pregnant women, and integrate STD prevention and treatment into prenatal care and other routine visits.
• People need to talk openly about STDs, get tested regularly, and reduce risk by using condoms or practicing mutual monogamy if sexually active.
• Parents and providers need to offer young people safe, effective ways to get information and services.
• State and local health departments should continue to direct resources to people hardest hit by the STD epidemic and work with community partners to maximize their impact.¹

STD CAMPAIGNS 100 YEARS AGO

This message sounds familiar. Let’s go back 100 years to World War I. The book No Magic Bullet by Allan M. Brandt² provides fascinating details about this period in America’s battle against venereal diseases. While the book is well worth reading in its entirety, I will attempt here to summarize the pertinent facts.

In the late 1910s, antivenereal campaigns were in full swing, with publicly shown movies such as “Fit to Fight” to train soldiers about STD symptoms and prevention to keep them physically healthy for fighting in the war. Similar information was widely available stateside for both men and women in open, matter-of-fact formats to encourage STD prevention.

After the war ended, the national sentiment became split between sexual revolution and social moralism. “Social hygienists” blamed the widespread increase in promiscuity on the newly introduced sexually explicit philosophy of Sigmund Freud, the widespread availability of automobiles (ie, a mobile, private, backseat location for sex), popular “vulgar” dances, and social feminism, among many others. The sexual revolution clearly led to an increased risk of STDs. But the antivenereal campaigns that had been appropriate in wartime came to be considered amoral and unfit for public consumption, and a period of silence about venereal diseases ensued.

By the 1930s, the situation had worsened:

• Approximately 1 out of every 10 Americans suffered from syphilis.
• Each year, Americans contracted almost half a million new syphilis infections (twice as many cases as tuberculosis, and 100 times as many cases as polio).
• 18% of all deaths from organic heart disease could be attributed to syphilis.
• Up to 20% of all mental institution inmates suffered from tertiary syphilis.
• 60,000 children were born each year with congenital syphilis.²

Although penicillin was still a decade or more away from discovery, syphilis could be treated, though likely not cured, with arsenic compounds. A course of treatment from a private physician, however, could cost from $300 to $1,000. Many patients who could not pay these exorbitant prices turned to public clinics for help. However, funding for the Venereal Disease Division of the Public Health Service, originally $4 million in 1920, was cut to less than $60,000 by 1926.² Some hospitals refused to admit patients with syphilis and other venereal diseases, deeming them “morally tainted and less deserving of care.”²

Things couldn’t get much worse.

Dr. Thomas Parran was the New York State health commissioner in 1930, at the start of the Great Depression. Realizing that arguments for moral responsibility to prevent and treat venereal diseases were not effective, Dr. Parran and other public health officials turned to financial arguments. Among the most persuasive arguments, “More than $15 million was spent annually for the ambulatory care of venereal patients…Experts argued that syphilis costs taxpayers between $40 and $50 million each year for the institutional care of the insane, paralyzed, and blind.”² The American Medical Association calculated that “8 to 10 million workers lost 21 million working days each year at an average of $4 a day as a result of infection with these conditions.”² The cost was estimated at more than $100,000,000 annually.²

But the general public was not a part of the larger conversation regarding treatment and prevention of syphilis, thanks to the social hygienists. In November 1934, Dr. Parran was scheduled to give a radio broadcast on future goals for public health in New York. Notified that he would not be able to mention syphilis or gonorrhea by name, he refused to give the speech. Dr. Parran went on to lead the charge to reduce the moral cloud that blocked the ability to address syphilis openly and scientifically. With his extensive experience in public health, he proposed plans that had been effective in controlling other infectious diseases as measures to control the spread of syphilis. He outlined the following:

• Identify cases of syphilis. Offer free diagnostic centers where individuals could obtain confidential blood tests.
• Offer prompt therapy for identified cases.
• Identify, locate, and test all contacts of infected patients, and treat them if they are infected too.
• Make blood testing mandatory before marriage and early in all pregnancies.
• Educate the public concerning syphilis.²

Do these approaches sound familiar?

Appointed US Surgeon General in 1936 by President Franklin Delano Roosevelt, Dr. Parran published “The next great plague to go,”³ an article focusing on the medical approach to treating syphilis and other venereal diseases, while refusing to address the moral and social issues.³ This was widely acclaimed by the public and the press. Two years after he was blocked from mentioning syphilis and gonorrhea on the radio, he was pictured on the cover of Time magazine for his groundbreaking work.

With the advent of penicillin, syphilis became not only treatable but curable. Over the next decades, the number of patients infected with syphilis and the morbidity it caused continually declined until the 1990s, when there were even whispers of eradication in the United States. This likely came in part due to the AIDS epidemic and the increased public discourse on safe sex.

However, the 1990s saw a new rise in cases of syphilis. This clearly could not be blamed on the social hygienists; rather, it was likely due to apathy and a decline in public health spending. We are now in a period of rapid rise in STDs.

We have the benefit of antibiotics. We have the benefit of hindsight. What we need is to heed the call to arms of Dr. Mermin, to be inspired by the wisdom of Dr. Parran, and to act. Identify the case of syphilis, offer treatment, educate the public. Drs. Coleman, Fiahlo, and Brateanu have accomplished all of these in their article in this issue of the Journal.⁴