CHICAGO – Because gastroparesis and functional dyspepsia share several symptoms (e.g., upper abdominal pain, fullness, and bloating) and pathophysiological abnormalities (e.g., delayed gastric emptying, impaired gastric accommodation, and visceral hypersensitivity), it can be hard to distinguish the two conditions, according to a lecture presented at Freston Conference 2019, sponsored by the American Gastroenterological Association. Additional research into the role of diet in these conditions will improve the treatment of these patients, said Linda Nguyen, MD, director of neurogastroenterology and motility at Stanford (Calif.) University.
Distinguishing the disorders
The accepted definition of gastroparesis is abnormal gastric emptying in the absence of a mechanical obstruction. The condition’s symptoms include nausea, vomiting, bloating, early satiety, abdominal pain, and weight loss. A previous consensus held that if a patient had abdominal pain, he or she did not have gastroparesis. Yet studies indicate that up to 80% of patients with gastroparesis have pain.
Functional dyspepsia is defined as bothersome postprandial fullness, early satiety, and epigastric pain or burning in the absence of structural abnormality. The disorder can be subdivided into postprandial distress (i.e., meal-related symptomatology) and epigastric pain syndrome (i.e., pain or burning that may or may not be related to meals). Either of these alternatives may entail nausea and vomiting.
Comparing the pathophysiologies of gastroparesis and functional dyspepsia helps to distinguish these disorders from each other. A 2019 review described rapid gastric emptying and duodenal eosinophilia in patients with functional dyspepsia, but not in patients with gastroparesis. Patients with epigastric pain syndrome had sensitivity to acid, bile, and fats. Patients with idiopathic gastroparesis, which is the most common type, had a weak antral pump and abnormal duodenal feedback, but patients with functional dyspepsia did not have these characteristics (J Neurogastroenterol Motil. 2019;25:27-35).
Examining symptoms and severity
One examination of patients with gastroparesis found that approximately 46% of them had a body mass index of 25 or greater. About 26% of patients had a BMI greater than 30. Yet these patients were eating less than 60% of their recommended daily allowances, based on their age, height, weight, and sex (Clin Gastroenterol Hepatol. 2011;9:1056-64).
Accelerating gastric emptying may not relieve symptoms completely in a patient with gastroparesis, said Dr. Nguyen. A 2007 study of patients with gastroparesis found that 43% had impaired accommodation, and 29% had visceral hypersensitivity (Gut. 2007;56:29-36). The same data indicated that gastric emptying time was not correlated with symptom severity. Impaired accommodation, however, was associated with early satiety and weight loss. Visceral hypersensitivity was associated with pain, early satiety, and weight loss. These data suggest that accommodation and visceral hypersensitivity may influence symptom severity in gastroparesis, said Dr. Nguyen.
Other researchers compared mild, moderate, and severe symptoms of early satiety in patients with gastroparesis. They found that patients with severe symptoms of early satiety have more delayed gastric emptying than do patients with mild or moderate symptoms of early satiety (Neurogastroenterol Motil. 2017;29.).
Dr. Nguyen and colleagues examined normal gastric emptying, compared with severely delayed gastric emptying, which they defined as greater than 35% retention at 4 hours. They found that severely delayed gastric emptying was associated with more severe symptoms, particularly nausea and vomiting, as measured by Gastroparesis Cardinal Symptom Index (GCSI). Extreme symptoms may help differentiate between gastroparesis and functional dyspepsia, said Dr. Nguyen.