Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content ++ Vestibular schwannomaAcoustic schwannomaCerebellopontine angle tumor ++ 225.1 Benign neoplasm of cranial nerves ++ D33.3 Benign neoplasm of cranial nerves ++ Pattern 5A: Primary Prevention/Risk Reduction for Loss of Balance and FallingPattern 5F: Impaired Peripheral Nerve Integrity and Muscle Performance Associated with Peripheral Nerve Injury +++ Description ++ Disorder of the vestibulocochlear nerve (8th cranial nerve) that carries vestibular and auditory input from the inner ear to the central nervous systemSlow-growing (usually 1 to 2 mm/year), benign tumor of the myelin-forming Schwann cells that surround the vestibular portion of the 8th cranial nerveTumor most commonly originates from the inferior vestibular branchTumor forms in the internal auditory canal and can extend into the cerebellopontine angleTypically results in a gradual onset of high-frequency sensorineural hearing loss, tinnitus, sense of ear fullness, unsteadiness, dizziness, or vertigoAs tumor grows, there may be facial nerve involvement (resulting in facial numbness or weakness), headache, hydrocephalus, incoordination, diplopia, hoarseness, difficulty swallowing, brainstem compression, or death +++ Essentials of Diagnosis ++ Physical exam normal unless the cerebellum or brainstem is compromised Audiogram abnormalImaging studies abnormalNeurotologic exam abnormalThorough and detailed history is essential to distinguish acoustic neuroma from other vestibular disorders and central pathology +++ General Considerations ++ Patients typically present with complaints of progressive hearing loss and loss of balance worsening gradually over several monthsOther typical symptoms include tinnitus (ringing or noises in the ear) and sense of ear fullnessPatients occasionally present with complaints of vertigo or vague report of dizzinessMay complain of blurred vision due to oscillopsia (perceived movement of the environment)If tumor growth progresses, may present with other cranial nerve (especially V and VII), brainstem, or cerebellar signs and symptoms +++ Demographics ++ Uncommon in general population, but most common cerebellopontine angle tumor (80% of these tumors)Unknown etiologyTypically occurs in 5th or 6th decade of lifeMortality has been nearly eliminated; morbidity rates have been significantly reduced due to improved techniques for early diagnosis and improved treatment approaches +++ Signs and Symptoms ++ Unexplained unilateral sensorineural hearing loss with high-frequency loss on audiogramImbalance, as manifested by difficulty standing and walkingIncreased risk of fallingVague sense of dizziness; may be constant or increasingly severe with head movementAbnormal auditory brainstem responseHypoactive or absent caloric responseAbnormal MRIMay observe nystagmus in room light or with fixation removedAbnormal neurotologic exam (impulse test, headshake test, dynamic visual acuity test, caloric test, VEMP test, or SVV test) May present with central symptoms, such as diplopia, dysarthria, dysphagia, dysmetria, numbness, or weakness if tumor has compressed brainstem or cerebellum +++ Functional Implications ++ Impedes balance and contribute to fallsProvokes dizziness ... Your MyAccess profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth