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