Benign Paroxysmal Positional Vertigo

Benign Paroxysmal Positional Vertigo (BPPV) is a mechanical disorder of the inner ear. It typically affects people over 50 years of age and can occur spontaneously or following head trauma or vestibular neuritis. The episodes of vertigo are brief, usually lasting 10–30 seconds, and always provoked by changes in head position relative to gravity (e.g., rolling over in bed, looking up, or leaning forward). Unlike Meniere's disease, there is no associated hearing loss or tinnitus. The gold standard for diagnosis is the Dix-Hallpike manoeuvre, which elicites a characteristic torsional, up-beating nystagmus. While the condition can be distressing, it is inherently 'benign' and often resolves spontaneously over weeks or months. However, the Epley manoeuvre offers immediate relief in over 80% of cases. It is vital to distinguish BPPV from 'Central' causes of positional vertigo (e.g., posterior fossa tumours or MS), which typically present with 'non-fatigueable' nystagmus and other neurological deficits.

BPPV is caused by 'canalolithiasis'. The utricle and saccule contain calcium carbonate crystals called otoconia (or 'ear stones') embedded in a gelatinous matrix. In BPPV, these otoconia become detached and migrate into one of the three semi-circular canals (90% end up in the posterior canal due to its anatomical position). When the head moves, these heavy crystals move within the endolymph of the canal, creating an abnormal drag on the cupula. This sends a false signal of rotation to the brain that conflicts with information from the other ear and the eyes, resulting in the sensation of vertigo and the characteristic nystagmus that matches the plane of the affected canal.

The patient describes sudden, short-lived room-spinning dizziness when turning in bed or bending down. They may feel 'off-balance' for hours after an attack due to vestibular 'after-effects', but the true vertigo is brief. Examination (Dix-Hallpike): The patient is moved from sitting to supine with the head turned 45 degrees. A positive result is the onset of nystagmus after a short latency (2-5 seconds). The nystagmus in posterior canal BPPV is 'geotropic' (beating towards the floor), rotatory, and 'fatigueable' (decreases with repeated testing). If nystagmus starts immediately, is purely vertical, or does not fatigue, suspect a central lesion.

- Bedside: Dix-Hallpike manoeuvre is the primary investigation. Cranial nerve and cerebellar exam to rule out central causes. Otoscopy is typically normal.
- Bloods: Not routinely indicated.
- Imaging: MRI Brain/Internal Auditory Meatus (IAM) only if there are atypical features (e.g., non-fatiguing nystagmus, neurological signs, or failure to respond to treatment).

Conservative: Reassurance that the condition is benign and self-limiting. Safety advice regarding driving and falls. Medical: Vestibular sedatives (e.g., Prochlorperazine) are NOT recommended for BPPV as they delay central compensation and do not stop the mechanical cause. Physical: The Epley manoeuvre (canalith repositioning procedure) is the first-line treatment. If BPPV affects the horizontal canal (rare), the 'Log-roll' (Lempert) manoeuvre is used. Brandt-Daroff exercises can be taught to the patient for home use if symptoms are persistent.