Benign paroxysmal positional vertigo
Overview
In Benign Paroxysmal Positional Vertigo (BPPV) dizziness is thought to be due to debris which has collected within a part of the inner ear. This debris can be thought of as "ear rocks", although the formal name is "otoconia". Ear rocks are small crystals of calcium carbonate derived from a structure in the ear called the "utricle"
Symptoms
* Vertigo: Spinning dizziness which is not light headed or off balance. * Short duration (Paroxysmal): Lasts only seconds to minutes * Positional in onset: Only can be induced by a change in position. * Nausea is often associated * Visual disturbance: It may be difficult to read or see during an attack due to the associated nystagmus.
Causes
Within the labyrinth of the inner ear lie collections of calcium crystals known as otoconia. In patients with BPPV, the otoconia are dislodged from their usual position within the utricle and they migrate over time into one of the semicircular canals (the posterior canal is most commonly affected due to its anatomical position). When the head is reoriented relative to gravity, the gravity-dependent movement of the heavier otoconial debris within the affected semicircular canal causes abnormal (pathological) fluid endolymph displacement and a resultant sensation of vertigo. This more common condition is known as canalithiasis.
Diagnosis
The condition is diagnosed from patient history (feeling of vertigo with sudden changes in positions); and by performing the Dix-Hallpike maneuver which is diagnostic for the condition. The test involves a reorientation of the head to align the posterior canal (at its entrance to the ampulla) with the direction of gravity. This test stimulus is effective in provoking the symptoms in subjects suffering from archetypal BPPV. These symptoms are typically a short lived vertigo, and observed nystagmus. In some patients, the vertigo can persist for years.
Treatment
The treatment of choice for this condition is the Epley canalith repositional maneuver which is effective in approximately 80% of patients[1]. The treatment employs gravity to move the calcium build-up that causes the condition