Acoustic Neuroma

 Acoustic Neuroma

Acoustic neuroma is also known as vestibular schwannoma.

Acoustic neuroma is benign tumor of myelin forming cells of vestibulocochlear nerve (CN VIII).

Etiology

1. Age 

Age between 30 to 60 years.

2. Genetic condition

Neurofibromatosis type 2 (NF2); primarily affect auditory nerves.

3. Exposure of high-dose ionizing radiation.

Pathophysiology

Overproduction of schwann cells wrap around nerve fiber.

Vestibular schwannoma grows and pressed against hearing and balance nerve.

Vestibular schwannoma press on facial nerve causing facial weakness or paralysis on side of tumor.

If tumor become large, it press against nearby brain structure.

Clinical Manifestations

1. Vertigo

2. Hearing loss

3. Tinnitus in affected ear

4. Nausea/vomiting

5. Headache

6. Loss of balance

7. Difficulty understanding speech

8. Pain in face or ear

9. Numbness in face or ear

10. Vision problem

11. Facial drooling on one side

Diagnostic Evaluation

1. MRI scan of head

2. CT scan of head

3. Hearing test (audiogram)

4. Electronystagmography

5. Brainstem auditory evoked response (BAER)

6. Caloric stimulation; test of vertigo

Management

Microsurgical Removal 

1. Translabyrinthine

Through the inner ear

2. Retrosigmoid or suboccipital (through skull behind ear)

Radiation Therapy

1. Gamma knife radiosurgery

Beams of gamma radiation

2. Stereotactic radiosurgery

Radiation to treat tumor