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Acoustic Neuroma
Aka: Acoustic Neuroma, Vestibular Schwannoma
- Pathophysiology
- Benign Acoustic Nerve tumor typically at cerebellopontine angle
- Majority of lesions arise from vestibular branch CN 8
- Epidemiology
- Represents 8% of all Brain Tumors
- Represents 80% of posterior fossa tumors
- Incidence: 1 per 100,000 persons in the United States
- Otolaryngologists sued most on missed Acoustic Neuroma
- Symptoms
- Unilateral and persistent Tinnitus beyond 1 month
- Gradually progressive unilateral Sensorineural Hearing Loss
- Represents only 1-2% of unilateral Hearing Loss causes
- Mild episodic Vertigo presenting symptom in 10% of cases
- Headache (later finding)
- Signs
- Typically normal exam
- Ataxia may be present
- Facial weakness or numbness may be present
- Diagnostics
- Pure tone Audiometry (formal testing with audiology)
- Asymmetric Hearing Loss may suggest Acoustic Neuroma
- Average difference >10 dB over 1 to 8 KHz range (high Test Sensitivity for Acoustic Neuroma)
- Average difference >15 dB over 0.5 to 3 KHz range (high Test Specificity for Acoustic Neuroma)
- Cheng (2012) Otolaryngol Head Neck Surg 146(3): 438-47 [PubMed]
- Other audiology evaluation
- Acoustic Reflex Testing
- Auditory Brainstem Testing (ABR)
- Electronystagmography (ENG)
- Abnormal in 50% of cases, but non-specific
- Imaging
- MRI brain with contrast and including Internal Auditory Canals
- Best study for identifying Acoustic Neuroma
- Replaces Auditory Brainstem Testing (ABR) for Acoustic Neuroma diagnosis
- Management
- Otolaryngology Referral for Surgical Excision
- Most otolaryngologists do not preserve hearing
- Hearing preservation technique has 50% success
- References
- Michels (2019) Am Fam Physician 100(2): 98-108 [PubMed]