Benign Paroxysmal Positional Vertigo

Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular disorder, characterised by brief episodes of vertigo provoked by changes in head position relative to gravity. It is caused by displaced otoconia from the utricle entering a semicircular canal, most often the posterior canal, and it is recognised at the bedside by a characteristic positional nystagmus.

Definition

BPPV is a disorder in which dislodged otoconial debris within a semicircular canal renders it abnormally sensitive to gravity, producing brief, recurrent, position-provoked vertigo accompanied by a stereotyped nystagmus.

Scope

This topic covers the mechanism of BPPV, its characteristic positional triggering and nystagmus, the diagnostic positional manoeuvres, and the principle of canalith repositioning. It is descriptive and educational; it summarises how the disorder is understood and assessed rather than directing individual care.

Core questions

• How do displaced otoconia produce position-triggered vertigo?
• Which positional manoeuvres provoke and identify the affected canal?
• How does canalith repositioning aim to resolve the symptom?

Key concepts

• Canalithiasis and cupulolithiasis
• Posterior, horizontal, and anterior canal variants
• Dix-Hallpike manoeuvre
• Supine roll (head-roll) test
• Positional nystagmus with latency and fatigability
• Canalith repositioning manoeuvres

Mechanisms

Otoconia normally embedded in the utricular macula can become dislodged and settle within a semicircular canal. When the head moves into a provoking position, the free-floating particles shift under gravity and abnormally deflect the cupula (the canalithiasis model), generating a brief burst of vertigo and a position-specific nystagmus with characteristic latency and fatigability. Because the geometry of each canal differs, the manoeuvre that provokes the symptom and the direction of the nystagmus localise the affected canal; repositioning manoeuvres use a sequence of head positions to guide the debris back out of the canal (Epley, 1992; Bhattacharyya et al., 2017).

Clinical relevance

BPPV is a frequent and treatable cause of dizziness, and its recognition rests on reproducing position-triggered vertigo and nystagmus with standard manoeuvres. Understanding it illustrates how mechanical inner-ear pathology maps onto a specific bedside test and physical treatment. This entry is educational and does not provide individualised diagnostic or treatment instructions.

Epidemiology

BPPV is the most common cause of vertigo of peripheral vestibular origin, occurs more often with increasing age and in women, and frequently recurs. The posterior semicircular canal is involved in the large majority of cases, with horizontal-canal variants next most common.

History

Positional vertigo with a typical nystagmus was described by Bárány and characterised in the mid-twentieth century through the Dix-Hallpike positional test. The canalithiasis understanding and the canalith repositioning procedure introduced by Epley in 1992 reframed BPPV as a mechanical, manoeuvre-treatable disorder, a view consolidated in subsequent clinical practice guidelines.

Key figures

• John Epley
• Joseph Furman
• Margaret Dix
• Charles Hallpike

Seminal works

• epley-1992
• furman-1999
• bhattacharyya-2017

Frequently asked questions

What causes benign paroxysmal positional vertigo?

It is caused by tiny calcium-carbonate crystals (otoconia) that have become dislodged from the utricle and entered a semicircular canal, making that canal abnormally responsive to gravity so that certain head positions trigger brief vertigo.

How is BPPV identified?

It is identified by positional manoeuvres such as the Dix-Hallpike test, which reproduce the vertigo and a characteristic nystagmus with a short latency that fatigues on repetition, helping localise the affected canal.