Dizziness

Question 1

CLINICAL ASSESSMENT:

Answer 1

1. Time course and duration
2. Associated with head movement?
   - usually peripheral lesion ie BPPV
3. Auditory dysfunction?
   - Deafness/tinnitus
   - Disturbance in labyrinth/vestibulocochlear nerve
   - Once in brainstem, auditory and vestibular function are separate
4. Medication
   - Anticonvulsant toxicity, aminoglycoside
5. Eye movements
   - Nystagmus without vertigo usually means CNS cause
6. CNS involvement ie ataxia, dysarthria, sensory and motor signs
   - Intracranial cause

Question 2

TYPES:

1. Intermittent Vertigo

Answer 2

1. a) Positional
   - BPPV most common
   - follows viral infection/head trauma. Also anticonvulsant, alcohol, central oculomotor disorders(rare)
   - Duration: few days.
   - Head movement triggers brief episodes of rotational vertigo
   - Hallpike’s test to show characteristic response, Epley’s maneuver to treat.

b) Non-positional
- Meniere’s disease most common cause: duration for hours; Associated hearing deficit and tinnitus; fullness in ear; spontaneous nystagmus during episodes, declining hearing in btw episodes.
- Other causes: otosclerosis, hyperviscosity syndromes, syphilitic labyrinthitis, Cogan’s syndrome
- CNS causes: Associated with brain stem dysfunction ie diplopia, ataxia, cranial nerve/limb deficits
- eg: Vertebrobasilar migraine(mainly children), multiple sclerosis, vertebrobasilar ischaemia(older adults)

2. Sustained vertigo
   - Trauma, Infection, Tumour, Infarction
   - Commonest cause: Idiopathic vestibular neuritis(usually 30-60y)
   - Acute onset, gaze-evoked nystagmus, canal-paresis on caloric testing, may prostate for around 1w
   - Infections: Lyme disease, syphilis, tuberculosis, herpes zoster(Ramsay Hunt syndrome)
   - Brain stem lesions: multiple sclerosis, infarction, tumours
3. Phobic vertigo
   - Non-discrete attacks
   - Associated hyperventilation
   - Could be following previous vestibular disturbance/primary psychogenic cause

Question 3

INVESTIGATIONS:

Answer 3

1. Hallpike’s manoeuvre
   - BPPV
   - delayed onset of nystagmus(5-30s), spontaneously resolves, fatiguable
2. Vestibulo-ocular response
   - doll’s eye movements: central or peripheral dysfunction
   - head thrust test: abnormal result usually indicates peripheral vestibular lesion
3. Caloric testing: COWS
   - Cold causes fast phase of nystagmus to the Opposite side and Warm to the Same side
4. Auditory evoked potential
   - tests delays in central auditory pathways
5. Audiometry
   - tests function of CN VIII
6. MRI
   - central vestibular disturbance
   - perform if associated unilateral hearing loss/presence of neurological signs

Question 4

TREATMENT:

Answer 4

1. For acute phase vertigo, vestibular sedatives:
   - Antihistamines(Betahistine, cinnarizine)
   - Dopamine antagonists(Prochlorperazine and metoclopramide), extra-pyramidal side-effects with long term use.
   - Anticholinergics(hyoscine), SE: dry mouth, constipation, urinary retention, confusion
   - Graded exercises after acute phase
2. Epley maneuver and Brandt-Darroff exercises for BPPV
3. ENT referral for Meniere’s disease.
   - Acetazolamide for prophylaxis
   - Surgical decompression of endolymph
4. Cognitive therapy for phobic postural vertigo
5. Steroids can be helpful for vestibular neuritis