Benign Paroxysmal Positional Vertigo
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Direct answer
Benign paroxysmal positional vertigo is the dislodgement of otoconia from the utricular macula into a semicircular canal — the posterior canal in the large majority — where floating debris turns head-position changes into false endolymph currents and brief, violent spinning. The history alone nearly makes the diagnosis: vertigo lasting well under a minute, provoked by turning in bed, looking up or bending, with a few seconds of latency, marked fatigability on repetition and no hearing loss or focal neurology. Dix-Hallpike provokes the geotropic torsional nystagmus that confirms it, and the Epley repositioning manoeuvre cures most patients at the bedside without any drug; recurrence over the following years, however, is common enough that patients must be taught to recognise it.
What you must remember
- Canal order: posterior canal in roughly 80-90 per cent of cases, horizontal canal next, anterior canal rare; antecedents include head trauma and prolonged bed rest, but most cases are idiopathic.
- Mechanism split: canalithiasis — free-floating debris causing paroxysmal nystagmus that fatigues (the usual picture); cupulolithiasis — debris adherent to the cupula causing persistent nystagmus as long as the position is held.
- Dix-Hallpike (Nylen-Barany) test: with the head turned 45 degrees toward the examined ear, the patient is laid supine with the head extended 20 degrees over the couch edge; latency of a few seconds, geotropic torsional-plus-upbeating nystagmus lasting under a minute, and fatigability on repetition constitute a positive test.
- Horizontal canal BPPV: diagnosed with the supine roll test; geotropic nystagmus that is stronger on one side localises the affected ear — the stronger side — while apogeotropic nystagmus suggests cupulolithiasis.
- Treatment by canal: posterior canal — Epley or Semont manoeuvre; horizontal canal — Lempert barbecue roll; Brandt-Daroff as the home programme.
- Drugs have no role in established BPPV: vestibular suppressants only dampen compensation and add sedation; they may be used briefly if nausea prevents manoeuvres.
- Red flags that overturn the diagnosis: vertical or downbeating nystagmus, absence of latency and fatigability, continuous vertigo, hearing loss, headache or ataxia — think central positional vertigo or posterior fossa lesion and image.
- Natural history: many resolve spontaneously over weeks, but recurrence over subsequent years is common enough that patients deserve advance counselling.
A typical exam case worked through
A 58-year-old woman reports that rolling onto her right side in bed triggers a 20-second spin with nausea for three weeks; she is normal between episodes and hears normally. With her head turned 45 degrees to the right, laying her supine with the head extended provokes, after a few seconds, torsional nystagmus beating toward the undermost right ear with an upbeating component, fatiguing within half a minute — posterior canal canalithiasis, right ear, the commonest vertigo diagnosis in any clinic.
Treat in the same visit with the Epley manoeuvre: sequential head positions walking the debris from the posterior canal to the common crus and utricle, each held about 30 seconds. Most patients clear in one or two sessions; teach Brandt-Daroff exercises for residual symptoms or recurrence, and review in a week. If manoeuvres instead provoke downbeating or unfatigable nystagmus, or she cannot stand or has dysarthria, stop and order magnetic resonance imaging — a posterior fossa lesion can imitate positional vertigo, and age with vascular risk demands respect.
Where students slip
Duration anchoring fails most: BPPV lasts seconds, Meniere disease tens of minutes, vestibular neuritis days — an all-day spin is not BPPV regardless of positional flavour. The second slip is ordering drugs or imaging first: the answer to classic positional vertigo is Dix-Hallpike then repositioning. Candidates also localise horizontal canal BPPV by the weaker side on the roll test — it is the stronger geotropic response that identifies the affected ear. Finally, avoid blaming cervical spondylosis for every positional symptom in an older patient before reproducing it with testing.
Frequently asked questions
Which semicircular canal is most often affected in BPPV?
The posterior canal, in roughly 80-90 per cent of cases, because gravity and its orientation make it the easiest resting place for dislodged otoconia.
How is the Dix-Hallpike test performed and what is a positive result?
With the head turned 45 degrees toward the tested ear, the patient is laid supine with head extended; latency of a few seconds followed by geotropic torsional, fatigable nystagmus with vertigo confirms posterior canal BPPV on that side.
What is the first-line treatment of posterior canal BPPV?
The Epley canalith repositioning manoeuvre, performed at the bedside, moving the head through sequential positions so the debris exits the canal into the utricle; the Semont manoeuvre is an alternative.
What are Brandt-Daroff exercises and when are they used?
A home exercise programme of repeated sitting-to-side-lying positions performed in sets several times daily, used for residual symptoms, recurrences, or when clinic manoeuvres are not tolerated.
When should BPPV-like vertigo raise suspicion of a central cause?
Downbeating or purely vertical nystagmus, absent latency and fatigability, continuous vertigo, or accompanying neurological signs indicate central positional vertigo and warrant MRI rather than manoeuvres.