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General Reference ⬇

Nejm 1991;324:1555

Pathophys and Cause ⬆ ⬇

Cause:Acoustic neuroma (AN); rarely neurofibromatosis type 2, bilateral acoustic neuromas (Jama 1997;278:51; Nejm 1988;318:684), autosomal dominant on chromosome 22; meningioma; metastatic cancer from lung, breast, prostate, kidney

Pathophys:ANs arise in vestibular portion of 8th nerve and gradually compress cranial nerves VIII and VII, then cerebellum, then IX, X, and XI

Epidemiology ⬆ ⬇

AN is most common; meningioma 2nd most common, and metastatic disease 3rd most common

Signs and Symptoms ⬆ ⬇

Sx:

  • Hearing loss unilaterally, sensorineural, 1st sx usually
  • Vertigo, mild, slowly progressive, unilateral
  • Tinnitus, unilateral often
  • Facial palsies
  • Dysphagia
  • Facial numbness

Si:Sensorineural hearing loss; ataxia, peripheral (eg, fingers), uncrossed; sensory deficits in cranial nerves, eg, distal VII (taste), and V (pin and touch); caloric testing shows no response on affected side (95%)

Course ⬆ ⬇

Neurofibromatosis type 2 onset in teens and 20s

Complications ⬆ ⬇

Neurofibromatosis type 2 is associated with meningiomas and gliomas

Lab and Xray ⬆ ⬇

Lab:

CSF:Shows elevated protein (67% of those with sx); present earlier in perilymph tap, if done

Noninv:Brainstem auditory evoked responses 100% positive (Nejm 1984;310:1740)

Xray:MRI with contrast; CT with contrast

Treatment ⬆

Rx:Surgical, stereotatic radiosurgery vs microsurgery (Nejm 1998;339:1426); in elderly, first follow with q 6 mo CT or MRI to be sure progressing

In neurofibromatosis type 2, Schwannomas can be shrunk w bevacizumab to improve hearing (Nejm 2009;361:358)