Benign paroxysmal positional vertigo (BPPV)
Benign paroxysmal positional vertigo (BPPV) is an inner-ear condition causing brief vertigo (a false sensation of spinning) on head movement, with transient nystagmus (jerky involuntary eye movements) and normal hearing.
Remember
In BPPV the vertigo is brief and triggered by head position, the nystagmus is typically transient, hearing is normal and the person feels well between episodes. Hearing loss, ringing in the ear or continuous vertigo suggests a different cause.
In BPPV (benign paroxysmal positional vertigo), tiny calcium carbonate crystals called otoconia have drifted out of the utricle, a balance organ in the inner ear, into a semicircular canal, a loop filled with fluid that senses head rotation. This is called canalithiasis, and it most often affects the posterior canal.
When the head moves, the loose crystals shift the fluid, and they go on stirring it for a moment once the head is still, which gives the brain a false signal about rotation. The brain responds with nystagmus and a brief spinning sensation.
Typical triggers are movements such as rolling over in bed or looking up. The episodes typically last under a minute, and the person feels well between them. Think of a snow globe: after a tilt the flakes swirl, and when it is held still they settle.
Hearing is unaffected, because the cochlea, the hearing organ, is not involved.
In the Dix-Hallpike test, the patient is laid back quickly with the head turned to one side. Nystagmus appears after a short delay, then fades, and it lessens when the test is repeated. This fading fits canalithiasis, where free-floating crystals settle. Persistent positional nystagmus, which lasts for as long as the head position is held, occurs in cupulolithiasis, where the crystals are attached rather than free-floating. The Epley manoeuvre, a series of head movements, helps the crystals leave the canal.
Key facts
- Mechanism
- displaced otoconia (calcium carbonate crystals) in a semicircular canal, most often the posterior canal
- Typical attack
- brief spinning vertigo, typically under a minute, triggered by head position, with the person feeling well between episodes
- Typical nystagmus
- transient, starting after a short delay on the Dix-Hallpike test and lessening when the test is repeated
- Hearing
- unaffected, with no hearing loss and no tinnitus (ringing or buzzing in the ear)
- Diagnosis
- the Dix-Hallpike test is used to diagnose it
- Treatment
- the Epley manoeuvre, a series of head movements that helps the crystals leave the canal
Exam traps
- Tinnitus (ringing or buzzing in the ear) together with a feeling of fullness in the ear is a feature of Ménière's disease (an inner-ear condition linked to excess fluid), not BPPV: BPPV involves only the balance canals, so hearing symptoms such as tinnitus are absent.
- Vertigo that goes on for days with no positional trigger is typical of vestibular neuritis (inflammation of the balance nerve), not BPPV, whose attacks settle within about a minute.
- Double vision with dizziness points to the brainstem or cerebellum, not BPPV, because canal crystals produce nystagmus without true double vision.
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