Grand Rounds: Woman, 22, With Dizziness and Headache

A 22-year-old student was brought in to a college student health center in a wheelchair by campus safety personnel. She appeared drowsy and was crying softly. She complained of a severe headache and said she was “tired of going through this all the time.” The woman said she had seen spots and become dizzy, then had gotten “the worst headache of my life” while sitting in class. She rated the headache pain at 8 on a 10-point scale and also complained of nausea and photophobia.

The history revealed dizziness that made her “feel as if I’m tipping over” and similar headaches during the previous year. The patient said she had seen “a few doctors” for her symptoms, but that they “could never find anything.” The headaches usually occurred on the left side of her head, lasted hours to days, and were only partially relieved with acetaminophen. The patient could not remember whether she had eaten breakfast and was unsure of what day it was. She described herself as frustrated and began to weep again.

She was currently under the care of a psychologist but seemed uncertain why; she said that she was sexually active and used condoms. She had undergone an appendectomy at age 12. She denied taking any medications besides acetaminophen. She denied smoking or drug use, history of migraine headaches, vision or hearing changes, facial weakness, depression, or anxiety. Her family history included a grandfather with diabetes and hypertension and an uncle with heart disease. The family history was negative for migraine or psychiatric illness.

Because of the patient’s weakness, she was assisted onto the examination table by a nurse. Physical exam revealed a pale, slightly sweaty, overweight, tearful young woman who was slow to respond. Her blood pressure was measured at 134/104 mm Hg; pulse, 100 beats/min; respirations, 14 breaths/min; and temperature, 97.0ºF. Point-of-care testing of blood glucose was 91 mg/dL, and hemoglobin was measured at 12.3 g/dL. The ophthalmologic exam was positive for photophobia and revealed slightly disconjugate gaze with horizontal nystagmus during testing of cranial nerves (CN) III, IV, and VI. The otoscopic exam revealed a slightly injected right tympanic membrane, and there were no apparent hearing deficits.

The neurologic exam showed patellar and brachial deep tendon reflexes equal, grips weak and equal, and the pupillary response intact. The patient was able to stand without assistance, although her gait was slightly unsteady. Because the patient was of college age, the clinician ruled out meningitis by negative Kernig’s and Brudzinski’s signs and absence of fever. Subarachnoid hemorrhage was also a concern when the patient mentioned the “worst headache of my life,” indicating the need for emergent imaging.

The patient’s presentation, it was felt, warranted a 911 call. The emergency medical team arrived, and its members began to question the patient. Discrepancies in the patient’s history during the paramedics’ reexamination led them to question whether an emergency department (ED) visit was necessary, but at the clinician’s insistence, they agreed to transport the student to the ED.

The following day, the student health center clinician was contacted by a member of the hospital ED staff with an update on the patient’s status. Shortly after her arrival at the hospital, she underwent MRI and was diagnosed with a vestibular schwannoma. She had surgery that same evening, during which the surgeon removed most of the tumor. Although the ED staff was not at liberty to provide more complete information, they did inform the clinician that the patient would require radiation for the remainder of the tumor.

DISCUSSION
Vestibular schwannoma is also known as acoustic schwannoma, acoustic neuroma, acoustic neurinoma, or vestibular neurilemmoma. These tumors arise from perineural elements of Schwann cells, which commonly form and lead to myelination in the vestibular area of CN VIII¹ (see figure). They occur with equal frequency on the superior and inferior branches of the vestibular nerve and originate only rarely at the cochlear portion of the eighth cranial nerve. Vestibular schwannomas represent approximately 8% to 10% of brain tumors and 80% to 90% of tumors in the cere­bellopontine angle in adults.² Tumors are distributed evenly across genders, but the majority of diagnosed patients are white.³

Most likely because of improvements in diagnostic technology, the incidence of vestibular schwannoma has increased over the past 30 years. One British research team predicts that one in 1,000 persons will receive a diagnosis of vestibular schwannoma in their lifetime.⁴ These tumors are most commonly diagnosed in people ages 30 to 60, with a median age of 55.⁵

A relationship has been demonstrated between neurofibromatosis type 2 (NF2), an autosomal-dominant disease, and the development of vestibular schwannomas.^6,7 NF2 has a birth prevalence of one in about 25,000 persons,^4,8 and those who inherit the responsible gene inevitably develop vestibular schwannomas.⁹ Patients with a confirmed diagnosis of vestibular schwannoma should be screened by a geneticist for the NF2 gene; although the tumors are benign, they can cause compression of the vestibular nerve, leading to deafness and balance disorders.¹⁰ Schwannomas of the spinal nerves can also occur in persons with NF2.¹¹ Compression of the spinal nerves in these patients can lead to significant morbidity and a shortened average life span.¹⁰

NF2 is diagnosed using the following criteria:

1) Bilateral vestibular schwan­nomas

2) Diagnosis of a family member with either NF2 or unilateral vestibular schwannoma, and

3) Juvenile posterior subscapular lens opacities.^9,12,13

Because schwannomas grow slowly, the vestibular system can adapt to the slow destruction of CN VIII. For this reason, patients typically present with unilateral deafness or hearing impairment rather than dizziness.¹¹ Many patients also present with tinnitus and/or vertigo.^14,15

Some vestibular tumors remain stable or even regress; others progress, in some cases causing life-threatening complications.¹⁶ An extremely rare complication of a vestibular schwannoma was reported in one patient: an intratumoral hemorrhage that led to acute neurologic deterioration and death.¹⁷

Since the case patient underwent immediate surgical intervention, it appears she was experiencing significant involvement and it was likely anticipated that without surgical intervention, clinical progression would occur. Her young age could be considered a risk factor for a faster-growing neuroma.¹⁸

Clinical Presentation and Diagnosis
Primary care clinicians commonly see patients with complaints of dizziness, lightheadedness, faintness, or a sensation of spinning or tilting. Vestibular schwannoma should be considered in the differential diagnosis of the patient who presents with these complaints, as well as tinnitus or hearing loss.⁹ The patient with vestibular schwannoma may also have a history of headache, unsteady gait, facial pain, and numbness.¹⁹ A partial differential diagnosis is listed in the table^20,21). The astute clinician will systematically rule out many of these conditions, since certain other features that may be present (eg, rapid onset, vomiting, fever) do not typically occur in the patient with vestibular schwannoma.

Because the symptoms typically associated with vestibular schwannoma are likely to occur bilaterally in patients with other conditions, unilateral symptoms should alert the clinician to investigate further. The patterns and growth rates of vestibular schwannomas are highly variable and currently unpredictable¹⁸ (according to Fortnum et al,¹⁴ at least 50% of tumors do not grow within several years after diagnosis); thus, no clear predictors of tumor growth have been identified to assist in the evaluation of an affected patient,¹⁶ although faster tumor growth rates have been reported in young patients, and Baser et al¹⁸ have called for additional research involving younger persons with vestibular schwannomas.

Standard testing is audiometry followed by MRI, which is considered the most effective means to confirm a diagnosis of vestibular schwannoma.^5,14,22

Treatment for Vestibular Schwannoma
Treatment, whether with surgery or radiation, is associated with significant morbidity and possibly decreased quality of life.¹⁶ Therefore, distinguishing patients whose tumors will grow and pose a threat to them from those whose tumors are likely to remain stable is central to appropriate management.²³

Treatment modalities are considered based on tumor size, growth, presence or absence of tinnitus, and the patient’s preferences and life expectancy.²³ In most cases, decision making is complex and should be customized to meet the patient’s individual circumstances. Patients with similar clinical scenarios have been reported to opt for different treatment choices.²⁴

Four treatment options are currently available for patients with vestibular schwannoma:

Serial observation with periodic MRI studies. Since vestibular schwannomas are benign and slow-growing, conservative manage­ment can be a reasonable option, particularly if the patient is elderly, the tumor is small, and/or little hearing loss has taken place. However, use of observation is associated with a risk for progressive and permanent hearing loss.² Between 15% and 50% of patients who opt for serial observation will undergo subsequent surgical intervention, particularly in cases involving worsening tinnitus, balance problems, or hearing loss.^23-25

Chemotherapy. Agents including bevacizumab (a humanized monoclonal antibody against vascular endothelial growth factor)^8,26,27 and erlotinib (an epidermal growth factor receptor inhibitor) may delay progression or even facilitate regression of vestibular schwannomas.²⁸ Hearing improvement has also been reported in patients with NF2 who were treated with bevacizumab⁸; research is ongoing.²⁶

Fractionated radiotherapy. Hearing may be preserved in 60% to 95% of patients, depending on levels of dosing to the cochlea, but 3% to 7% of patients will need further treatment.^29-31 Radiation treatment is a likely choice in patients with tumors measuring 2.0 cm or less. Larger tumors are considered a surgical disease, and directed radiotherapy may be administered postoperatively (as in the case patient) for residual portions of the tumor.¹⁶

Microsurgery. Compared with other treatment modalities, the emphasis of microsurgery is on removing tumors (particularly larger tumors) rather than controlling their growth.²⁹ The three common approaches are retrosigmoid, middle fossa, or translabyrinthine.^32-34 Preservation of hearing is reportedly better following retrosigmoid or middle fossa microsurgery, compared with a translabyrinthine procedure (because in the latter, the tumor cannot be exposed without damage to the inner ear).^32,35

With any such surgery, risks include cranial nerve damage, leakage of cerebrospinal fluid, and infection.^29,32 Postsurgically, about half of patients report frequent headaches, which are persistent in about half of these cases.^36-38 Another concern is preservation of the facial nerves, with a risk for temporary facial weakness or dysfunction.^3,24,39 Less than 2% of patients who undergo microsurgery require additional treatment.²⁹

Stereotactic radiosurgery. These procedures, which are performed using the Gamma Knife,^® the CyberKnife, or the linear accelerator,^29,40,41 are considered appropriate for patients with smaller tumors and those who are not candidates for conventional surgery.¹ Trigeminal neuropathy, injury to the facial nerves, and hydrocephaly are reported complications of Gamma Knife radiosurgery, but improvements in these technologies are ongoing.^1,2,40

Patient Outcomes
The outcome in a patient with vestibular schwannoma depends on the treatment administered, but prolonged follow-up is typically necessary. For patients being managed through observation, annual brain scans are recommended for 10 years, with subsequent scans every three to five years if no tumor growth is seen. For patients who have had surgery, annual brain scans are advised for the successive eight to 10 years, with decreasing frequency if no tumor remains. In patients who undergo radiation, annual scans are recommended for 10 years, then every two years if no tumor growth is detected.³⁶

Psychosocial experiences vary widely among patients who have undergone treatment for vestibular schwannomas. Some are unable to perform necessary or recreational activities, and others must retire early from work.⁴² Others, however, have minimal disruption in their lives and enjoy a good quality of life. The most difficult consequence of vestibular schwannoma and its treatment, according to patients, is the associated hearing loss.^8,19

THE CASE PATIENT
The 22-year-old patient in this case had an atypical presentation of vestibular schwannoma. Although she did present with vertigo, she also complained of headache, nausea, and photophobia—which are rarely reported in investigations of these tumors. She was also younger than the typical patient and did not report tinnitus.

The case patient reportedly underwent surgery and subsequent radiation to treat the remaining portion of her tumor. She suspended her attendance at the college and, as of this writing, has not re-enrolled. She was lost to follow-up.

CONCLUSION
For the primary care provider, diagnostic challenges require great clinical acumen. Vertigo, headache, hearing loss, and tinnitus are all symptoms seen in the primary care setting; when they occur together, the clinician should be alerted to investigate further. A high level of suspicion is appropriate when a patient complains of longstanding auditory symptoms, with or without headache. Unilateral hearing loss is a common symptom in patients with vestibular schwannomas, although some may present with facial weakness or pain, imbalance, and/or vertigo.

In addition to the history and physical exam, experts recommend that audiometry and MRI be considered, particularly if hearing loss is unilateral. Genetic screening for NF2 should be performed if vestibular schwannoma is found on MRI. Referral to a neurologist, a neurosurgeon, or an otolaryngologist is appropriate.

REFERENCES
1. Arthurs BJ, Lamoreaux WT, Giddings NA, et al. Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature. World J Surg Oncol. 2009 Dec 18;7:100.

2. Mohammed TA, Ahuja MS, Ju SS, Thomas J. Normal pressure hydrocephalus after Gamma Knife radiosurgery for vestibular schwannoma. J Postgrad Med. 2010;56(3):213-215.

3. Gal TJ, Shinn J, Huang B. Current epidemiology and management trends in acoustic neuroma. Otolaryngol Head Neck Surg. 2010;142(5):677-681.

4. Evans DG, Moran A, King A, et al. Incidence of vestibular schwannoma and neurofibromatosis 2 in the North West of England over a 10-year period: higher incidence than previously thought. Otol Neurotol. 2005;26(1):93-97.

5. Haynes D. Acoustic neuroma diagnosis and treatment options. Hearing Health. 2009;25(3):32. www.drf.org/magazine/36/Summer+2009+Issue/article/272. Accessed May 16, 2011.

6. Sobel RA. Vestibular (acoustic) schwannomas: histologic features in neurofibromatosis 2 and in unilateral cases. J Neuropathol Exp Neurol. 1993;52(2):106-113.

7. Evans DG, Huson SM, Donnai D, et al. A clinical study of type 2 neurofibromatosis. Q J Med. 1992;84(304):603-618.

8. Plotkin SR, Stemmer-Rachamimov AO, Barker FG 2nd, et al. Hearing improvement after bevacizumab in patients with neurofibromatosis type 2. N Engl J Med. 2009;361(4):358-367.

9. Evans DGR, Sainio M, Baser E. Neurofibromatosis type 2. J Med Genet. 2000:37(11):897-904.

10. Gusella JF, Ramesh V, MacCollin M, Jacoby LB. Neurofibromatosis 2: loss of Merlin’s protective spell. Curr Opin Genet Dev. 1996;6(1):87-92.

11. Sagar SM, Israel MA. Ch 374. Primary and metastatic tumors of the nervous system. In: Kasper DL, Braunwald E, Fauci AS, et al. Harrison’s Principles of Internal Medicine. 17th ed. New York, NY: McGraw-Hill Companies, Inc; 2008:2601-2610.

12. Evans DGR. Neurofibromatosis 2 [bilateral acoustic neurofibromatosis, central neurofibromatosis, NF2, neurofibromatosis type II]. Genet Med. 2009;11(9):599-610.

13. Arya R, Sahu JK, Kabra M. Neurofibromatosis type II (Wishart type). J Pediatr Neurol. 2009;7(3): 333-335.

14. Fortnum H, O’Neill C, Taylor R, et al. The role of magnetic resonance imaging in the identification of suspected acoustic neuroma: a systematic review of clinical and cost effectiveness and natural history. Health Technol Assess. 2009;13(18):iii-iv, ix-xi, 1-154.

15. Forton GE, Cremers CW, Offeciers EE. Acoustic neuroma ingrowth in the cochlear nerve: does it influence the clinical presentation? Ann Otol Rhinol Laryngol. 2004;113(7):582-586.

16. Nikolopoulos TP, Fortnum H, O’Donoghue G, Baguley D. Acoustic neuroma growth: a systematic review of the evidence. Otol Neurotol. 2010;31(3):478-485.

17. Yates CW, Weinberg M, Packer MJ, Jacob A. Fatal case of tumor-associated hemorrhage in a large vestibular schwannoma. Ann Otol Rhinol Laryngol. 2010;119(6):402-405.

18. Baser ME, Mautner VF, Parry DM, Evans DGR. Methodological issues in longitudinal studies; vestibular schwannoma growth rates in neurofibromatosis 2. J Med Genet. 2005;42(12):903-906.

19. Brooker J, Burney S, Fletcher J, Dally M. A qualitative exploration of quality of life among individuals diagnosed with an acoustic neuroma. Br J Health Psychol. 2009;14(pt 3):563-578.

20. Strupp M, Brandt T. Diagnosis and treatment of vertigo and dizziness. Dtsch Arzetbl Int. 2008;105(10):173-180.

21. Kerber KA. Dizziness and vertigo. In: Andreoli TE, Griggs RC, Benjamin I , Wing EJ, eds. Andreoli and Carpenter’s Cecil Essentials of Medicine. 8th ed. Philadelphia, PA: Elsevier Inc; 2010:1104-1105.

22. Gimsing S. Vestibular schwannoma: when to look for it? J Laryngol Otol. 2010;124(3):258-264.

23. Agrawal Y, Clark JH, Limb CJ, et al. Predictors of vestibular schwannoma growth and clinical implications. Otol Neurotol. 2010;31(5):807-812.

24. Cheung SW, Aranda D, Driscoll CLW, Parsa AT. Mapping clinical outcomes expectations to treatment decisions: an application to vestibular schwannoma management. Otol Neurotol. 2010;31(2):284-293.

25. Myrseth E, Pedersen PH, Møller P, Lund-Johansen M. Treatment of vestibular schwannomas: why, when and how? Acta Neurochir (Wien). 2007;149(7):647-660.

26. Sidney Kimmel Comprehensive Cancer Center, Massachusetts General Hospital, National Cancer Institute. Bevacizumab for symptomatic vestibular schwannoma in neurofibromatosis type 2 (NF2). http://clinicaltrials.gov/ct2/show/NCT01207687. Accessed May 16, 2011.

27. Mautner VF, Nguyen R, Kutta H, et al. Bevacizumab induces regression of vestibular schwannomas in patients with neurofibromatosis type 2. Neuro Oncol. 2010;12(1):14-18.

28. Plotkin SR, Halpin C, McKenna MJ, et al. Erlotinib for progressive vestibular schwannoma in neurofibromatosis 2 patients. Otol Neurotol. 2010;31(7):1135-1143.

29. Arthurs BJ, Fairbanks RK, Demakas JJ, et al. A review of treatment modalities for vestibular schwannoma. Neurosurg Rev. 2011 Feb 9; [Epub ahead of print].

30. Andrews DW, Werner-Wasik M, Den RB, et al. Toward dose optimization for fractionated stereotactic radiotherapy for acoustic neuromas: comparison of two dose cohorts. Int J Radiat Oncol Biol Phys. 2009;74(2):419-426.

31. Thomas C, Di Maio S, Ma R, et al. Hearing preservation following fractionated stereotactic radiotherapy for vestibular schwannomas: prognostic implications of cochlear dose. J Neurosurg. 2007;107(5):917-926.

32. Samii M, Gerganov V, Samii A. Improved preservation of hearing and facial nerve function in vestibular schwannoma surgery via the retrosigmoid approach in a series of 200 patients. J Neuro­surg. 2006;105(4):527-535.

33. Shiobara R, Ohira T, Inoue Y, et al. Extended middle cranial fossa approach for vestibular schwannoma: technical note and surgical results of 896 operations. Prog Neurol Surg. 2008;21:65-72.

34. Schmerber S, Palombi O, Boubagra K, et al. Long-term control of vestibular schwannoma after a translabyrinthine complete removal. Neurosurgery. 2005;57(4):693-698.

35. Phillips DJ, Kobylarz EJ, De Peralta ET, et al. Predictive factors of hearing preservation after surgical resection of small vestibular schwannomas. Otol Neurotol. 2010;31(9):1463-1468.

36. Park JK, Black MP, Vernick DM, Ramakrishna N. Vestibular schwannoma (acoustic neuroma) (2010). www.uptodate.com/contents/vestibular-schwannoma-acoustic-neuroma. Accessed May 16, 2011.

37. Schankin CJ, Gall C, Straube A. Headache syndromes after acoustic neuroma surgery and their implications for quality of life. Cephalalgia. 2009;29(7):760-761.

38. Ryzenman JM, Pensak ML, Tew JM Jr. Headache: a quality of life analysis in a cohort of 1,657 patients undergoing acoustic neuroma surgery: results from the Acoustic Neuroma Association. Laryngoscope. 2005;115(4):703-711.

39. Sriskandan N, Connor SE. The role of radiology in the diagnosis and management of vestibular schwannoma. Clin Radiol. 2010;66(4):357-365.

40. Yang I, Sughrue ME, Han SJ, et al. Facial nerve preservation after vestibular schwannoma Gamma Knife surgery. J Neurooncol. 2009;93(1): 41-48.

41. Unger F, Dominikus K, Haselsberger K. Stereotactic radiosurgery and fractionated stereotactic radiotherapy of acoustic neuromas [in German]. HNO. 2011;59(1):31-37.

42. Tos T, Caye-Thomasen P, Stangerup SE, et al. Long-term socio-economic impact of vestibular schwannoma for patients under observation and after surgery. J Laryngol Otol. 2003;117(12):955-964.

A 22-year-old student was brought in to a college student health center in a wheelchair by campus safety personnel. She appeared drowsy and was crying softly. She complained of a severe headache and said she was “tired of going through this all the time.” The woman said she had seen spots and become dizzy, then had gotten “the worst headache of my life” while sitting in class. She rated the headache pain at 8 on a 10-point scale and also complained of nausea and photophobia.

The history revealed dizziness that made her “feel as if I’m tipping over” and similar headaches during the previous year. The patient said she had seen “a few doctors” for her symptoms, but that they “could never find anything.” The headaches usually occurred on the left side of her head, lasted hours to days, and were only partially relieved with acetaminophen. The patient could not remember whether she had eaten breakfast and was unsure of what day it was. She described herself as frustrated and began to weep again.

She was currently under the care of a psychologist but seemed uncertain why; she said that she was sexually active and used condoms. She had undergone an appendectomy at age 12. She denied taking any medications besides acetaminophen. She denied smoking or drug use, history of migraine headaches, vision or hearing changes, facial weakness, depression, or anxiety. Her family history included a grandfather with diabetes and hypertension and an uncle with heart disease. The family history was negative for migraine or psychiatric illness.

Because of the patient’s weakness, she was assisted onto the examination table by a nurse. Physical exam revealed a pale, slightly sweaty, overweight, tearful young woman who was slow to respond. Her blood pressure was measured at 134/104 mm Hg; pulse, 100 beats/min; respirations, 14 breaths/min; and temperature, 97.0ºF. Point-of-care testing of blood glucose was 91 mg/dL, and hemoglobin was measured at 12.3 g/dL. The ophthalmologic exam was positive for photophobia and revealed slightly disconjugate gaze with horizontal nystagmus during testing of cranial nerves (CN) III, IV, and VI. The otoscopic exam revealed a slightly injected right tympanic membrane, and there were no apparent hearing deficits.

The neurologic exam showed patellar and brachial deep tendon reflexes equal, grips weak and equal, and the pupillary response intact. The patient was able to stand without assistance, although her gait was slightly unsteady. Because the patient was of college age, the clinician ruled out meningitis by negative Kernig’s and Brudzinski’s signs and absence of fever. Subarachnoid hemorrhage was also a concern when the patient mentioned the “worst headache of my life,” indicating the need for emergent imaging.

The patient’s presentation, it was felt, warranted a 911 call. The emergency medical team arrived, and its members began to question the patient. Discrepancies in the patient’s history during the paramedics’ reexamination led them to question whether an emergency department (ED) visit was necessary, but at the clinician’s insistence, they agreed to transport the student to the ED.

The following day, the student health center clinician was contacted by a member of the hospital ED staff with an update on the patient’s status. Shortly after her arrival at the hospital, she underwent MRI and was diagnosed with a vestibular schwannoma. She had surgery that same evening, during which the surgeon removed most of the tumor. Although the ED staff was not at liberty to provide more complete information, they did inform the clinician that the patient would require radiation for the remainder of the tumor.

DISCUSSION
Vestibular schwannoma is also known as acoustic schwannoma, acoustic neuroma, acoustic neurinoma, or vestibular neurilemmoma. These tumors arise from perineural elements of Schwann cells, which commonly form and lead to myelination in the vestibular area of CN VIII¹ (see figure). They occur with equal frequency on the superior and inferior branches of the vestibular nerve and originate only rarely at the cochlear portion of the eighth cranial nerve. Vestibular schwannomas represent approximately 8% to 10% of brain tumors and 80% to 90% of tumors in the cere­bellopontine angle in adults.² Tumors are distributed evenly across genders, but the majority of diagnosed patients are white.³

Most likely because of improvements in diagnostic technology, the incidence of vestibular schwannoma has increased over the past 30 years. One British research team predicts that one in 1,000 persons will receive a diagnosis of vestibular schwannoma in their lifetime.⁴ These tumors are most commonly diagnosed in people ages 30 to 60, with a median age of 55.⁵

A relationship has been demonstrated between neurofibromatosis type 2 (NF2), an autosomal-dominant disease, and the development of vestibular schwannomas.^6,7 NF2 has a birth prevalence of one in about 25,000 persons,^4,8 and those who inherit the responsible gene inevitably develop vestibular schwannomas.⁹ Patients with a confirmed diagnosis of vestibular schwannoma should be screened by a geneticist for the NF2 gene; although the tumors are benign, they can cause compression of the vestibular nerve, leading to deafness and balance disorders.¹⁰ Schwannomas of the spinal nerves can also occur in persons with NF2.¹¹ Compression of the spinal nerves in these patients can lead to significant morbidity and a shortened average life span.¹⁰

NF2 is diagnosed using the following criteria:

1) Bilateral vestibular schwan­nomas

2) Diagnosis of a family member with either NF2 or unilateral vestibular schwannoma, and

3) Juvenile posterior subscapular lens opacities.^9,12,13

Because schwannomas grow slowly, the vestibular system can adapt to the slow destruction of CN VIII. For this reason, patients typically present with unilateral deafness or hearing impairment rather than dizziness.¹¹ Many patients also present with tinnitus and/or vertigo.^14,15

Some vestibular tumors remain stable or even regress; others progress, in some cases causing life-threatening complications.¹⁶ An extremely rare complication of a vestibular schwannoma was reported in one patient: an intratumoral hemorrhage that led to acute neurologic deterioration and death.¹⁷

Since the case patient underwent immediate surgical intervention, it appears she was experiencing significant involvement and it was likely anticipated that without surgical intervention, clinical progression would occur. Her young age could be considered a risk factor for a faster-growing neuroma.¹⁸

Clinical Presentation and Diagnosis
Primary care clinicians commonly see patients with complaints of dizziness, lightheadedness, faintness, or a sensation of spinning or tilting. Vestibular schwannoma should be considered in the differential diagnosis of the patient who presents with these complaints, as well as tinnitus or hearing loss.⁹ The patient with vestibular schwannoma may also have a history of headache, unsteady gait, facial pain, and numbness.¹⁹ A partial differential diagnosis is listed in the table^20,21). The astute clinician will systematically rule out many of these conditions, since certain other features that may be present (eg, rapid onset, vomiting, fever) do not typically occur in the patient with vestibular schwannoma.

Because the symptoms typically associated with vestibular schwannoma are likely to occur bilaterally in patients with other conditions, unilateral symptoms should alert the clinician to investigate further. The patterns and growth rates of vestibular schwannomas are highly variable and currently unpredictable¹⁸ (according to Fortnum et al,¹⁴ at least 50% of tumors do not grow within several years after diagnosis); thus, no clear predictors of tumor growth have been identified to assist in the evaluation of an affected patient,¹⁶ although faster tumor growth rates have been reported in young patients, and Baser et al¹⁸ have called for additional research involving younger persons with vestibular schwannomas.

Standard testing is audiometry followed by MRI, which is considered the most effective means to confirm a diagnosis of vestibular schwannoma.^5,14,22

Treatment for Vestibular Schwannoma
Treatment, whether with surgery or radiation, is associated with significant morbidity and possibly decreased quality of life.¹⁶ Therefore, distinguishing patients whose tumors will grow and pose a threat to them from those whose tumors are likely to remain stable is central to appropriate management.²³

Treatment modalities are considered based on tumor size, growth, presence or absence of tinnitus, and the patient’s preferences and life expectancy.²³ In most cases, decision making is complex and should be customized to meet the patient’s individual circumstances. Patients with similar clinical scenarios have been reported to opt for different treatment choices.²⁴

Four treatment options are currently available for patients with vestibular schwannoma:

Serial observation with periodic MRI studies. Since vestibular schwannomas are benign and slow-growing, conservative manage­ment can be a reasonable option, particularly if the patient is elderly, the tumor is small, and/or little hearing loss has taken place. However, use of observation is associated with a risk for progressive and permanent hearing loss.² Between 15% and 50% of patients who opt for serial observation will undergo subsequent surgical intervention, particularly in cases involving worsening tinnitus, balance problems, or hearing loss.^23-25

Chemotherapy. Agents including bevacizumab (a humanized monoclonal antibody against vascular endothelial growth factor)^8,26,27 and erlotinib (an epidermal growth factor receptor inhibitor) may delay progression or even facilitate regression of vestibular schwannomas.²⁸ Hearing improvement has also been reported in patients with NF2 who were treated with bevacizumab⁸; research is ongoing.²⁶

Fractionated radiotherapy. Hearing may be preserved in 60% to 95% of patients, depending on levels of dosing to the cochlea, but 3% to 7% of patients will need further treatment.^29-31 Radiation treatment is a likely choice in patients with tumors measuring 2.0 cm or less. Larger tumors are considered a surgical disease, and directed radiotherapy may be administered postoperatively (as in the case patient) for residual portions of the tumor.¹⁶

Microsurgery. Compared with other treatment modalities, the emphasis of microsurgery is on removing tumors (particularly larger tumors) rather than controlling their growth.²⁹ The three common approaches are retrosigmoid, middle fossa, or translabyrinthine.^32-34 Preservation of hearing is reportedly better following retrosigmoid or middle fossa microsurgery, compared with a translabyrinthine procedure (because in the latter, the tumor cannot be exposed without damage to the inner ear).^32,35

With any such surgery, risks include cranial nerve damage, leakage of cerebrospinal fluid, and infection.^29,32 Postsurgically, about half of patients report frequent headaches, which are persistent in about half of these cases.^36-38 Another concern is preservation of the facial nerves, with a risk for temporary facial weakness or dysfunction.^3,24,39 Less than 2% of patients who undergo microsurgery require additional treatment.²⁹

Stereotactic radiosurgery. These procedures, which are performed using the Gamma Knife,^® the CyberKnife, or the linear accelerator,^29,40,41 are considered appropriate for patients with smaller tumors and those who are not candidates for conventional surgery.¹ Trigeminal neuropathy, injury to the facial nerves, and hydrocephaly are reported complications of Gamma Knife radiosurgery, but improvements in these technologies are ongoing.^1,2,40

Patient Outcomes
The outcome in a patient with vestibular schwannoma depends on the treatment administered, but prolonged follow-up is typically necessary. For patients being managed through observation, annual brain scans are recommended for 10 years, with subsequent scans every three to five years if no tumor growth is seen. For patients who have had surgery, annual brain scans are advised for the successive eight to 10 years, with decreasing frequency if no tumor remains. In patients who undergo radiation, annual scans are recommended for 10 years, then every two years if no tumor growth is detected.³⁶

Psychosocial experiences vary widely among patients who have undergone treatment for vestibular schwannomas. Some are unable to perform necessary or recreational activities, and others must retire early from work.⁴² Others, however, have minimal disruption in their lives and enjoy a good quality of life. The most difficult consequence of vestibular schwannoma and its treatment, according to patients, is the associated hearing loss.^8,19

THE CASE PATIENT
The 22-year-old patient in this case had an atypical presentation of vestibular schwannoma. Although she did present with vertigo, she also complained of headache, nausea, and photophobia—which are rarely reported in investigations of these tumors. She was also younger than the typical patient and did not report tinnitus.

The case patient reportedly underwent surgery and subsequent radiation to treat the remaining portion of her tumor. She suspended her attendance at the college and, as of this writing, has not re-enrolled. She was lost to follow-up.

CONCLUSION
For the primary care provider, diagnostic challenges require great clinical acumen. Vertigo, headache, hearing loss, and tinnitus are all symptoms seen in the primary care setting; when they occur together, the clinician should be alerted to investigate further. A high level of suspicion is appropriate when a patient complains of longstanding auditory symptoms, with or without headache. Unilateral hearing loss is a common symptom in patients with vestibular schwannomas, although some may present with facial weakness or pain, imbalance, and/or vertigo.

In addition to the history and physical exam, experts recommend that audiometry and MRI be considered, particularly if hearing loss is unilateral. Genetic screening for NF2 should be performed if vestibular schwannoma is found on MRI. Referral to a neurologist, a neurosurgeon, or an otolaryngologist is appropriate.

REFERENCES
1. Arthurs BJ, Lamoreaux WT, Giddings NA, et al. Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature. World J Surg Oncol. 2009 Dec 18;7:100.

2. Mohammed TA, Ahuja MS, Ju SS, Thomas J. Normal pressure hydrocephalus after Gamma Knife radiosurgery for vestibular schwannoma. J Postgrad Med. 2010;56(3):213-215.

3. Gal TJ, Shinn J, Huang B. Current epidemiology and management trends in acoustic neuroma. Otolaryngol Head Neck Surg. 2010;142(5):677-681.

4. Evans DG, Moran A, King A, et al. Incidence of vestibular schwannoma and neurofibromatosis 2 in the North West of England over a 10-year period: higher incidence than previously thought. Otol Neurotol. 2005;26(1):93-97.

5. Haynes D. Acoustic neuroma diagnosis and treatment options. Hearing Health. 2009;25(3):32. www.drf.org/magazine/36/Summer+2009+Issue/article/272. Accessed May 16, 2011.

6. Sobel RA. Vestibular (acoustic) schwannomas: histologic features in neurofibromatosis 2 and in unilateral cases. J Neuropathol Exp Neurol. 1993;52(2):106-113.

7. Evans DG, Huson SM, Donnai D, et al. A clinical study of type 2 neurofibromatosis. Q J Med. 1992;84(304):603-618.

8. Plotkin SR, Stemmer-Rachamimov AO, Barker FG 2nd, et al. Hearing improvement after bevacizumab in patients with neurofibromatosis type 2. N Engl J Med. 2009;361(4):358-367.

9. Evans DGR, Sainio M, Baser E. Neurofibromatosis type 2. J Med Genet. 2000:37(11):897-904.

10. Gusella JF, Ramesh V, MacCollin M, Jacoby LB. Neurofibromatosis 2: loss of Merlin’s protective spell. Curr Opin Genet Dev. 1996;6(1):87-92.

11. Sagar SM, Israel MA. Ch 374. Primary and metastatic tumors of the nervous system. In: Kasper DL, Braunwald E, Fauci AS, et al. Harrison’s Principles of Internal Medicine. 17th ed. New York, NY: McGraw-Hill Companies, Inc; 2008:2601-2610.

12. Evans DGR. Neurofibromatosis 2 [bilateral acoustic neurofibromatosis, central neurofibromatosis, NF2, neurofibromatosis type II]. Genet Med. 2009;11(9):599-610.

13. Arya R, Sahu JK, Kabra M. Neurofibromatosis type II (Wishart type). J Pediatr Neurol. 2009;7(3): 333-335.

14. Fortnum H, O’Neill C, Taylor R, et al. The role of magnetic resonance imaging in the identification of suspected acoustic neuroma: a systematic review of clinical and cost effectiveness and natural history. Health Technol Assess. 2009;13(18):iii-iv, ix-xi, 1-154.

15. Forton GE, Cremers CW, Offeciers EE. Acoustic neuroma ingrowth in the cochlear nerve: does it influence the clinical presentation? Ann Otol Rhinol Laryngol. 2004;113(7):582-586.

16. Nikolopoulos TP, Fortnum H, O’Donoghue G, Baguley D. Acoustic neuroma growth: a systematic review of the evidence. Otol Neurotol. 2010;31(3):478-485.

17. Yates CW, Weinberg M, Packer MJ, Jacob A. Fatal case of tumor-associated hemorrhage in a large vestibular schwannoma. Ann Otol Rhinol Laryngol. 2010;119(6):402-405.

18. Baser ME, Mautner VF, Parry DM, Evans DGR. Methodological issues in longitudinal studies; vestibular schwannoma growth rates in neurofibromatosis 2. J Med Genet. 2005;42(12):903-906.

19. Brooker J, Burney S, Fletcher J, Dally M. A qualitative exploration of quality of life among individuals diagnosed with an acoustic neuroma. Br J Health Psychol. 2009;14(pt 3):563-578.

20. Strupp M, Brandt T. Diagnosis and treatment of vertigo and dizziness. Dtsch Arzetbl Int. 2008;105(10):173-180.

21. Kerber KA. Dizziness and vertigo. In: Andreoli TE, Griggs RC, Benjamin I , Wing EJ, eds. Andreoli and Carpenter’s Cecil Essentials of Medicine. 8th ed. Philadelphia, PA: Elsevier Inc; 2010:1104-1105.

22. Gimsing S. Vestibular schwannoma: when to look for it? J Laryngol Otol. 2010;124(3):258-264.

23. Agrawal Y, Clark JH, Limb CJ, et al. Predictors of vestibular schwannoma growth and clinical implications. Otol Neurotol. 2010;31(5):807-812.

24. Cheung SW, Aranda D, Driscoll CLW, Parsa AT. Mapping clinical outcomes expectations to treatment decisions: an application to vestibular schwannoma management. Otol Neurotol. 2010;31(2):284-293.

25. Myrseth E, Pedersen PH, Møller P, Lund-Johansen M. Treatment of vestibular schwannomas: why, when and how? Acta Neurochir (Wien). 2007;149(7):647-660.

26. Sidney Kimmel Comprehensive Cancer Center, Massachusetts General Hospital, National Cancer Institute. Bevacizumab for symptomatic vestibular schwannoma in neurofibromatosis type 2 (NF2). http://clinicaltrials.gov/ct2/show/NCT01207687. Accessed May 16, 2011.

27. Mautner VF, Nguyen R, Kutta H, et al. Bevacizumab induces regression of vestibular schwannomas in patients with neurofibromatosis type 2. Neuro Oncol. 2010;12(1):14-18.

28. Plotkin SR, Halpin C, McKenna MJ, et al. Erlotinib for progressive vestibular schwannoma in neurofibromatosis 2 patients. Otol Neurotol. 2010;31(7):1135-1143.

29. Arthurs BJ, Fairbanks RK, Demakas JJ, et al. A review of treatment modalities for vestibular schwannoma. Neurosurg Rev. 2011 Feb 9; [Epub ahead of print].

30. Andrews DW, Werner-Wasik M, Den RB, et al. Toward dose optimization for fractionated stereotactic radiotherapy for acoustic neuromas: comparison of two dose cohorts. Int J Radiat Oncol Biol Phys. 2009;74(2):419-426.

31. Thomas C, Di Maio S, Ma R, et al. Hearing preservation following fractionated stereotactic radiotherapy for vestibular schwannomas: prognostic implications of cochlear dose. J Neurosurg. 2007;107(5):917-926.

32. Samii M, Gerganov V, Samii A. Improved preservation of hearing and facial nerve function in vestibular schwannoma surgery via the retrosigmoid approach in a series of 200 patients. J Neuro­surg. 2006;105(4):527-535.

33. Shiobara R, Ohira T, Inoue Y, et al. Extended middle cranial fossa approach for vestibular schwannoma: technical note and surgical results of 896 operations. Prog Neurol Surg. 2008;21:65-72.

34. Schmerber S, Palombi O, Boubagra K, et al. Long-term control of vestibular schwannoma after a translabyrinthine complete removal. Neurosurgery. 2005;57(4):693-698.

35. Phillips DJ, Kobylarz EJ, De Peralta ET, et al. Predictive factors of hearing preservation after surgical resection of small vestibular schwannomas. Otol Neurotol. 2010;31(9):1463-1468.

36. Park JK, Black MP, Vernick DM, Ramakrishna N. Vestibular schwannoma (acoustic neuroma) (2010). www.uptodate.com/contents/vestibular-schwannoma-acoustic-neuroma. Accessed May 16, 2011.

37. Schankin CJ, Gall C, Straube A. Headache syndromes after acoustic neuroma surgery and their implications for quality of life. Cephalalgia. 2009;29(7):760-761.

38. Ryzenman JM, Pensak ML, Tew JM Jr. Headache: a quality of life analysis in a cohort of 1,657 patients undergoing acoustic neuroma surgery: results from the Acoustic Neuroma Association. Laryngoscope. 2005;115(4):703-711.

39. Sriskandan N, Connor SE. The role of radiology in the diagnosis and management of vestibular schwannoma. Clin Radiol. 2010;66(4):357-365.

40. Yang I, Sughrue ME, Han SJ, et al. Facial nerve preservation after vestibular schwannoma Gamma Knife surgery. J Neurooncol. 2009;93(1): 41-48.

41. Unger F, Dominikus K, Haselsberger K. Stereotactic radiosurgery and fractionated stereotactic radiotherapy of acoustic neuromas [in German]. HNO. 2011;59(1):31-37.

42. Tos T, Caye-Thomasen P, Stangerup SE, et al. Long-term socio-economic impact of vestibular schwannoma for patients under observation and after surgery. J Laryngol Otol. 2003;117(12):955-964.

A 22-year-old student was brought in to a college student health center in a wheelchair by campus safety personnel. She appeared drowsy and was crying softly. She complained of a severe headache and said she was “tired of going through this all the time.” The woman said she had seen spots and become dizzy, then had gotten “the worst headache of my life” while sitting in class. She rated the headache pain at 8 on a 10-point scale and also complained of nausea and photophobia.

The history revealed dizziness that made her “feel as if I’m tipping over” and similar headaches during the previous year. The patient said she had seen “a few doctors” for her symptoms, but that they “could never find anything.” The headaches usually occurred on the left side of her head, lasted hours to days, and were only partially relieved with acetaminophen. The patient could not remember whether she had eaten breakfast and was unsure of what day it was. She described herself as frustrated and began to weep again.

She was currently under the care of a psychologist but seemed uncertain why; she said that she was sexually active and used condoms. She had undergone an appendectomy at age 12. She denied taking any medications besides acetaminophen. She denied smoking or drug use, history of migraine headaches, vision or hearing changes, facial weakness, depression, or anxiety. Her family history included a grandfather with diabetes and hypertension and an uncle with heart disease. The family history was negative for migraine or psychiatric illness.

Because of the patient’s weakness, she was assisted onto the examination table by a nurse. Physical exam revealed a pale, slightly sweaty, overweight, tearful young woman who was slow to respond. Her blood pressure was measured at 134/104 mm Hg; pulse, 100 beats/min; respirations, 14 breaths/min; and temperature, 97.0ºF. Point-of-care testing of blood glucose was 91 mg/dL, and hemoglobin was measured at 12.3 g/dL. The ophthalmologic exam was positive for photophobia and revealed slightly disconjugate gaze with horizontal nystagmus during testing of cranial nerves (CN) III, IV, and VI. The otoscopic exam revealed a slightly injected right tympanic membrane, and there were no apparent hearing deficits.

The neurologic exam showed patellar and brachial deep tendon reflexes equal, grips weak and equal, and the pupillary response intact. The patient was able to stand without assistance, although her gait was slightly unsteady. Because the patient was of college age, the clinician ruled out meningitis by negative Kernig’s and Brudzinski’s signs and absence of fever. Subarachnoid hemorrhage was also a concern when the patient mentioned the “worst headache of my life,” indicating the need for emergent imaging.

The patient’s presentation, it was felt, warranted a 911 call. The emergency medical team arrived, and its members began to question the patient. Discrepancies in the patient’s history during the paramedics’ reexamination led them to question whether an emergency department (ED) visit was necessary, but at the clinician’s insistence, they agreed to transport the student to the ED.

The following day, the student health center clinician was contacted by a member of the hospital ED staff with an update on the patient’s status. Shortly after her arrival at the hospital, she underwent MRI and was diagnosed with a vestibular schwannoma. She had surgery that same evening, during which the surgeon removed most of the tumor. Although the ED staff was not at liberty to provide more complete information, they did inform the clinician that the patient would require radiation for the remainder of the tumor.

DISCUSSION
Vestibular schwannoma is also known as acoustic schwannoma, acoustic neuroma, acoustic neurinoma, or vestibular neurilemmoma. These tumors arise from perineural elements of Schwann cells, which commonly form and lead to myelination in the vestibular area of CN VIII¹ (see figure). They occur with equal frequency on the superior and inferior branches of the vestibular nerve and originate only rarely at the cochlear portion of the eighth cranial nerve. Vestibular schwannomas represent approximately 8% to 10% of brain tumors and 80% to 90% of tumors in the cere­bellopontine angle in adults.² Tumors are distributed evenly across genders, but the majority of diagnosed patients are white.³

Most likely because of improvements in diagnostic technology, the incidence of vestibular schwannoma has increased over the past 30 years. One British research team predicts that one in 1,000 persons will receive a diagnosis of vestibular schwannoma in their lifetime.⁴ These tumors are most commonly diagnosed in people ages 30 to 60, with a median age of 55.⁵

A relationship has been demonstrated between neurofibromatosis type 2 (NF2), an autosomal-dominant disease, and the development of vestibular schwannomas.^6,7 NF2 has a birth prevalence of one in about 25,000 persons,^4,8 and those who inherit the responsible gene inevitably develop vestibular schwannomas.⁹ Patients with a confirmed diagnosis of vestibular schwannoma should be screened by a geneticist for the NF2 gene; although the tumors are benign, they can cause compression of the vestibular nerve, leading to deafness and balance disorders.¹⁰ Schwannomas of the spinal nerves can also occur in persons with NF2.¹¹ Compression of the spinal nerves in these patients can lead to significant morbidity and a shortened average life span.¹⁰

NF2 is diagnosed using the following criteria:

1) Bilateral vestibular schwan­nomas

2) Diagnosis of a family member with either NF2 or unilateral vestibular schwannoma, and

3) Juvenile posterior subscapular lens opacities.^9,12,13

Because schwannomas grow slowly, the vestibular system can adapt to the slow destruction of CN VIII. For this reason, patients typically present with unilateral deafness or hearing impairment rather than dizziness.¹¹ Many patients also present with tinnitus and/or vertigo.^14,15

Some vestibular tumors remain stable or even regress; others progress, in some cases causing life-threatening complications.¹⁶ An extremely rare complication of a vestibular schwannoma was reported in one patient: an intratumoral hemorrhage that led to acute neurologic deterioration and death.¹⁷

Since the case patient underwent immediate surgical intervention, it appears she was experiencing significant involvement and it was likely anticipated that without surgical intervention, clinical progression would occur. Her young age could be considered a risk factor for a faster-growing neuroma.¹⁸

Clinical Presentation and Diagnosis
Primary care clinicians commonly see patients with complaints of dizziness, lightheadedness, faintness, or a sensation of spinning or tilting. Vestibular schwannoma should be considered in the differential diagnosis of the patient who presents with these complaints, as well as tinnitus or hearing loss.⁹ The patient with vestibular schwannoma may also have a history of headache, unsteady gait, facial pain, and numbness.¹⁹ A partial differential diagnosis is listed in the table^20,21). The astute clinician will systematically rule out many of these conditions, since certain other features that may be present (eg, rapid onset, vomiting, fever) do not typically occur in the patient with vestibular schwannoma.

Because the symptoms typically associated with vestibular schwannoma are likely to occur bilaterally in patients with other conditions, unilateral symptoms should alert the clinician to investigate further. The patterns and growth rates of vestibular schwannomas are highly variable and currently unpredictable¹⁸ (according to Fortnum et al,¹⁴ at least 50% of tumors do not grow within several years after diagnosis); thus, no clear predictors of tumor growth have been identified to assist in the evaluation of an affected patient,¹⁶ although faster tumor growth rates have been reported in young patients, and Baser et al¹⁸ have called for additional research involving younger persons with vestibular schwannomas.

Standard testing is audiometry followed by MRI, which is considered the most effective means to confirm a diagnosis of vestibular schwannoma.^5,14,22

Treatment for Vestibular Schwannoma
Treatment, whether with surgery or radiation, is associated with significant morbidity and possibly decreased quality of life.¹⁶ Therefore, distinguishing patients whose tumors will grow and pose a threat to them from those whose tumors are likely to remain stable is central to appropriate management.²³

Treatment modalities are considered based on tumor size, growth, presence or absence of tinnitus, and the patient’s preferences and life expectancy.²³ In most cases, decision making is complex and should be customized to meet the patient’s individual circumstances. Patients with similar clinical scenarios have been reported to opt for different treatment choices.²⁴

Four treatment options are currently available for patients with vestibular schwannoma:

Serial observation with periodic MRI studies. Since vestibular schwannomas are benign and slow-growing, conservative manage­ment can be a reasonable option, particularly if the patient is elderly, the tumor is small, and/or little hearing loss has taken place. However, use of observation is associated with a risk for progressive and permanent hearing loss.² Between 15% and 50% of patients who opt for serial observation will undergo subsequent surgical intervention, particularly in cases involving worsening tinnitus, balance problems, or hearing loss.^23-25

Chemotherapy. Agents including bevacizumab (a humanized monoclonal antibody against vascular endothelial growth factor)^8,26,27 and erlotinib (an epidermal growth factor receptor inhibitor) may delay progression or even facilitate regression of vestibular schwannomas.²⁸ Hearing improvement has also been reported in patients with NF2 who were treated with bevacizumab⁸; research is ongoing.²⁶

Fractionated radiotherapy. Hearing may be preserved in 60% to 95% of patients, depending on levels of dosing to the cochlea, but 3% to 7% of patients will need further treatment.^29-31 Radiation treatment is a likely choice in patients with tumors measuring 2.0 cm or less. Larger tumors are considered a surgical disease, and directed radiotherapy may be administered postoperatively (as in the case patient) for residual portions of the tumor.¹⁶

Microsurgery. Compared with other treatment modalities, the emphasis of microsurgery is on removing tumors (particularly larger tumors) rather than controlling their growth.²⁹ The three common approaches are retrosigmoid, middle fossa, or translabyrinthine.^32-34 Preservation of hearing is reportedly better following retrosigmoid or middle fossa microsurgery, compared with a translabyrinthine procedure (because in the latter, the tumor cannot be exposed without damage to the inner ear).^32,35

With any such surgery, risks include cranial nerve damage, leakage of cerebrospinal fluid, and infection.^29,32 Postsurgically, about half of patients report frequent headaches, which are persistent in about half of these cases.^36-38 Another concern is preservation of the facial nerves, with a risk for temporary facial weakness or dysfunction.^3,24,39 Less than 2% of patients who undergo microsurgery require additional treatment.²⁹

Stereotactic radiosurgery. These procedures, which are performed using the Gamma Knife,^® the CyberKnife, or the linear accelerator,^29,40,41 are considered appropriate for patients with smaller tumors and those who are not candidates for conventional surgery.¹ Trigeminal neuropathy, injury to the facial nerves, and hydrocephaly are reported complications of Gamma Knife radiosurgery, but improvements in these technologies are ongoing.^1,2,40

Patient Outcomes
The outcome in a patient with vestibular schwannoma depends on the treatment administered, but prolonged follow-up is typically necessary. For patients being managed through observation, annual brain scans are recommended for 10 years, with subsequent scans every three to five years if no tumor growth is seen. For patients who have had surgery, annual brain scans are advised for the successive eight to 10 years, with decreasing frequency if no tumor remains. In patients who undergo radiation, annual scans are recommended for 10 years, then every two years if no tumor growth is detected.³⁶

Psychosocial experiences vary widely among patients who have undergone treatment for vestibular schwannomas. Some are unable to perform necessary or recreational activities, and others must retire early from work.⁴² Others, however, have minimal disruption in their lives and enjoy a good quality of life. The most difficult consequence of vestibular schwannoma and its treatment, according to patients, is the associated hearing loss.^8,19

THE CASE PATIENT
The 22-year-old patient in this case had an atypical presentation of vestibular schwannoma. Although she did present with vertigo, she also complained of headache, nausea, and photophobia—which are rarely reported in investigations of these tumors. She was also younger than the typical patient and did not report tinnitus.

The case patient reportedly underwent surgery and subsequent radiation to treat the remaining portion of her tumor. She suspended her attendance at the college and, as of this writing, has not re-enrolled. She was lost to follow-up.

CONCLUSION
For the primary care provider, diagnostic challenges require great clinical acumen. Vertigo, headache, hearing loss, and tinnitus are all symptoms seen in the primary care setting; when they occur together, the clinician should be alerted to investigate further. A high level of suspicion is appropriate when a patient complains of longstanding auditory symptoms, with or without headache. Unilateral hearing loss is a common symptom in patients with vestibular schwannomas, although some may present with facial weakness or pain, imbalance, and/or vertigo.

In addition to the history and physical exam, experts recommend that audiometry and MRI be considered, particularly if hearing loss is unilateral. Genetic screening for NF2 should be performed if vestibular schwannoma is found on MRI. Referral to a neurologist, a neurosurgeon, or an otolaryngologist is appropriate.

REFERENCES
1. Arthurs BJ, Lamoreaux WT, Giddings NA, et al. Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature. World J Surg Oncol. 2009 Dec 18;7:100.

2. Mohammed TA, Ahuja MS, Ju SS, Thomas J. Normal pressure hydrocephalus after Gamma Knife radiosurgery for vestibular schwannoma. J Postgrad Med. 2010;56(3):213-215.

3. Gal TJ, Shinn J, Huang B. Current epidemiology and management trends in acoustic neuroma. Otolaryngol Head Neck Surg. 2010;142(5):677-681.

4. Evans DG, Moran A, King A, et al. Incidence of vestibular schwannoma and neurofibromatosis 2 in the North West of England over a 10-year period: higher incidence than previously thought. Otol Neurotol. 2005;26(1):93-97.

5. Haynes D. Acoustic neuroma diagnosis and treatment options. Hearing Health. 2009;25(3):32. www.drf.org/magazine/36/Summer+2009+Issue/article/272. Accessed May 16, 2011.

6. Sobel RA. Vestibular (acoustic) schwannomas: histologic features in neurofibromatosis 2 and in unilateral cases. J Neuropathol Exp Neurol. 1993;52(2):106-113.

7. Evans DG, Huson SM, Donnai D, et al. A clinical study of type 2 neurofibromatosis. Q J Med. 1992;84(304):603-618.

8. Plotkin SR, Stemmer-Rachamimov AO, Barker FG 2nd, et al. Hearing improvement after bevacizumab in patients with neurofibromatosis type 2. N Engl J Med. 2009;361(4):358-367.

9. Evans DGR, Sainio M, Baser E. Neurofibromatosis type 2. J Med Genet. 2000:37(11):897-904.

10. Gusella JF, Ramesh V, MacCollin M, Jacoby LB. Neurofibromatosis 2: loss of Merlin’s protective spell. Curr Opin Genet Dev. 1996;6(1):87-92.

11. Sagar SM, Israel MA. Ch 374. Primary and metastatic tumors of the nervous system. In: Kasper DL, Braunwald E, Fauci AS, et al. Harrison’s Principles of Internal Medicine. 17th ed. New York, NY: McGraw-Hill Companies, Inc; 2008:2601-2610.

12. Evans DGR. Neurofibromatosis 2 [bilateral acoustic neurofibromatosis, central neurofibromatosis, NF2, neurofibromatosis type II]. Genet Med. 2009;11(9):599-610.

13. Arya R, Sahu JK, Kabra M. Neurofibromatosis type II (Wishart type). J Pediatr Neurol. 2009;7(3): 333-335.

14. Fortnum H, O’Neill C, Taylor R, et al. The role of magnetic resonance imaging in the identification of suspected acoustic neuroma: a systematic review of clinical and cost effectiveness and natural history. Health Technol Assess. 2009;13(18):iii-iv, ix-xi, 1-154.

15. Forton GE, Cremers CW, Offeciers EE. Acoustic neuroma ingrowth in the cochlear nerve: does it influence the clinical presentation? Ann Otol Rhinol Laryngol. 2004;113(7):582-586.

16. Nikolopoulos TP, Fortnum H, O’Donoghue G, Baguley D. Acoustic neuroma growth: a systematic review of the evidence. Otol Neurotol. 2010;31(3):478-485.

17. Yates CW, Weinberg M, Packer MJ, Jacob A. Fatal case of tumor-associated hemorrhage in a large vestibular schwannoma. Ann Otol Rhinol Laryngol. 2010;119(6):402-405.

18. Baser ME, Mautner VF, Parry DM, Evans DGR. Methodological issues in longitudinal studies; vestibular schwannoma growth rates in neurofibromatosis 2. J Med Genet. 2005;42(12):903-906.

19. Brooker J, Burney S, Fletcher J, Dally M. A qualitative exploration of quality of life among individuals diagnosed with an acoustic neuroma. Br J Health Psychol. 2009;14(pt 3):563-578.

20. Strupp M, Brandt T. Diagnosis and treatment of vertigo and dizziness. Dtsch Arzetbl Int. 2008;105(10):173-180.

21. Kerber KA. Dizziness and vertigo. In: Andreoli TE, Griggs RC, Benjamin I , Wing EJ, eds. Andreoli and Carpenter’s Cecil Essentials of Medicine. 8th ed. Philadelphia, PA: Elsevier Inc; 2010:1104-1105.

22. Gimsing S. Vestibular schwannoma: when to look for it? J Laryngol Otol. 2010;124(3):258-264.

23. Agrawal Y, Clark JH, Limb CJ, et al. Predictors of vestibular schwannoma growth and clinical implications. Otol Neurotol. 2010;31(5):807-812.

24. Cheung SW, Aranda D, Driscoll CLW, Parsa AT. Mapping clinical outcomes expectations to treatment decisions: an application to vestibular schwannoma management. Otol Neurotol. 2010;31(2):284-293.

25. Myrseth E, Pedersen PH, Møller P, Lund-Johansen M. Treatment of vestibular schwannomas: why, when and how? Acta Neurochir (Wien). 2007;149(7):647-660.

26. Sidney Kimmel Comprehensive Cancer Center, Massachusetts General Hospital, National Cancer Institute. Bevacizumab for symptomatic vestibular schwannoma in neurofibromatosis type 2 (NF2). http://clinicaltrials.gov/ct2/show/NCT01207687. Accessed May 16, 2011.

27. Mautner VF, Nguyen R, Kutta H, et al. Bevacizumab induces regression of vestibular schwannomas in patients with neurofibromatosis type 2. Neuro Oncol. 2010;12(1):14-18.

28. Plotkin SR, Halpin C, McKenna MJ, et al. Erlotinib for progressive vestibular schwannoma in neurofibromatosis 2 patients. Otol Neurotol. 2010;31(7):1135-1143.

29. Arthurs BJ, Fairbanks RK, Demakas JJ, et al. A review of treatment modalities for vestibular schwannoma. Neurosurg Rev. 2011 Feb 9; [Epub ahead of print].

30. Andrews DW, Werner-Wasik M, Den RB, et al. Toward dose optimization for fractionated stereotactic radiotherapy for acoustic neuromas: comparison of two dose cohorts. Int J Radiat Oncol Biol Phys. 2009;74(2):419-426.

31. Thomas C, Di Maio S, Ma R, et al. Hearing preservation following fractionated stereotactic radiotherapy for vestibular schwannomas: prognostic implications of cochlear dose. J Neurosurg. 2007;107(5):917-926.

32. Samii M, Gerganov V, Samii A. Improved preservation of hearing and facial nerve function in vestibular schwannoma surgery via the retrosigmoid approach in a series of 200 patients. J Neuro­surg. 2006;105(4):527-535.

33. Shiobara R, Ohira T, Inoue Y, et al. Extended middle cranial fossa approach for vestibular schwannoma: technical note and surgical results of 896 operations. Prog Neurol Surg. 2008;21:65-72.

34. Schmerber S, Palombi O, Boubagra K, et al. Long-term control of vestibular schwannoma after a translabyrinthine complete removal. Neurosurgery. 2005;57(4):693-698.

35. Phillips DJ, Kobylarz EJ, De Peralta ET, et al. Predictive factors of hearing preservation after surgical resection of small vestibular schwannomas. Otol Neurotol. 2010;31(9):1463-1468.

36. Park JK, Black MP, Vernick DM, Ramakrishna N. Vestibular schwannoma (acoustic neuroma) (2010). www.uptodate.com/contents/vestibular-schwannoma-acoustic-neuroma. Accessed May 16, 2011.

37. Schankin CJ, Gall C, Straube A. Headache syndromes after acoustic neuroma surgery and their implications for quality of life. Cephalalgia. 2009;29(7):760-761.

38. Ryzenman JM, Pensak ML, Tew JM Jr. Headache: a quality of life analysis in a cohort of 1,657 patients undergoing acoustic neuroma surgery: results from the Acoustic Neuroma Association. Laryngoscope. 2005;115(4):703-711.

39. Sriskandan N, Connor SE. The role of radiology in the diagnosis and management of vestibular schwannoma. Clin Radiol. 2010;66(4):357-365.

40. Yang I, Sughrue ME, Han SJ, et al. Facial nerve preservation after vestibular schwannoma Gamma Knife surgery. J Neurooncol. 2009;93(1): 41-48.

41. Unger F, Dominikus K, Haselsberger K. Stereotactic radiosurgery and fractionated stereotactic radiotherapy of acoustic neuromas [in German]. HNO. 2011;59(1):31-37.

42. Tos T, Caye-Thomasen P, Stangerup SE, et al. Long-term socio-economic impact of vestibular schwannoma for patients under observation and after surgery. J Laryngol Otol. 2003;117(12):955-964.