Cranial Nerve Palsy - VIII : Vestibulocochlear Nerve

Question 1

Anatomical Course of Vestibulocochlear Nerve.

Answer 1

1. Vestibular Nucleus Complex in Pons and Medulla.
2. Cochlear - Ventral and Dorsal Cochlear Nuclei in Inferior Cerebellar Peduncle.
3. Combine in pons to form Nerve.
4. Emerges from Brain at Cerebellopontine Angle.
5. Leaves Cranium through Internal Acoustic Meatus.
6. Splits into nerves.

Question 2

Sensory Function of Vestibulocochlear Nerve.

Answer 2

1. Cochlear : Hearing.

2. Vestibular : Balance.

Question 3

What is a Basilar Skull Fracture?

Answer 3

A fracture at the skull base resulting from major trauma which can damage the Vestibulocochlear Nerve.

Question 4

What is Vestibular Neuritis?

Answer 4

Inflammation of Vestibular Branch - usually reactivation of HSV.

Question 5

Clinical Features of Vestibular Neuritis (4).

Answer 5

1. Vertigo.
2. Nystagmus.
3. Loss of Equilibrium.
4. Nausea and Vomiting.
5. NO HEARING LOSS/TINNITUS.

Question 6

Management of Vestibular Neuritis.

Answer 6

1. Self-resolving : symptomatic e.g. anti-emetics e.g. Prochlorperazine Oral, vestibular suppressants.
2. Vestibular Rehabilitation Exercise - Chronic Symptoms.
3. Rapid Relief - Buccal/IM Prochlorperazine.

Question 7

What is Labyrinthitis?

Answer 7

Inflammation of Membranous Labyrinth - damage to nerve.

Question 8

Clinical Features of Labyrinthitis (3).

Answer 8

ACUTE Onset :

1. Same as Vestibular Neuritis.
2. Cochlear. Damage : Sensorineural Hearing Loss.
3. Cochlear Damage : Tinnitus.

Question 9

Management of Labyrinthitis (2).

Answer 9

1. Self-Limiting.

2. Prochlorperazine and Antihistamines - Dizziness.

Question 10

What is an Acoustic Neuroma?

Answer 10

Vestibular Schwannoma.

Question 11

Epidemiology of Acoustic Neuromas (3).

Answer 11

1. 5% of Intracranial Tumours.
2. 90% of Cerebellopontine Angle Tumours.
3. Association : Neurofibromatosis Type II.

Question 12

Clinical Features of Acoustic Neuromas (4).

Answer 12

1. Vertigo (VIII).
2. Hearing Loss (VIII).
3. Tinnitus (VIII).
4. Absent Corneal Reflex (V).

Question 13

Management of Acoustic Neuromas (4).

Answer 13

1. Refer urgently to ENT (though slow-growing and benign).
2. MRI of Cerebellopontine Angle - Investigation of Choice.
3. Audiometry.
4. Surgery, Radiotherapy or Observation.