Benign Positional Vertigo Health Article

Definition

Benign positional vertigo (BPV) is the most common cause of dizziness due to an impairment of the balance center in the ear.

Description

BPV was first described by Adler in 1987. Dix and Hallpike named the disorder benign paroxysmal positional vertigo. The disorder can also be called canalithiasis or positional vertigo or "top shelf vertigo" (affected persons tip their heads back to look up when having an attack).

The internal ear consists of sacs, ducts, and bone. The internal portion of the ear can be divided into the bony labyrinth and membranous labyrinth. The bony labyrinth is a cave-like area composed of three parts: the cochlea, vestibule, and semicircular canals. The shell-shaped cochlea is the organ for hearing. The vestibule is a small oval chamber that contains two structures, the utricle and the saccule, responsible for balance. A membrane within the utricle and saccule normally contains particles called otoliths (calcium carbonate particles). The semicircular canals that occupy three planes in space contain the semicircular ducts for fluid (endolymph) flow.

The Canalolithiasis Theory, the most widely accepted explanation for the cause of BPV, explains the actual mechanism that causes BPV. The theory is that otoliths can become displaced from the utricle and enter a portion of the semicircular ducts. Changing head position can cause free otoliths to gravitate longitudinally through the canal. The endolymph fluid contained in the semicircular canal will flow abnormally, causing stimulation of special sensors (hair cells) of the affected posterior semicircular canal duct. This stimulation causes vertigo or dizziness.

Demographics

In the United States, the number of new cases (incidence) is 64 cases per 100,000 populations per year. The incidence is greater in patients older than 40 years, and women are affected twice more often than men. Several studies indicate that an average age of onset in the mid-50s. Approximately 20% of all falls by the elderly, resulting in hospitalization for serious injuries, are due to vertigo (dizziness). No information is available concerning predilection to race. Approximately 25–40% of patients with BPV express dizziness as their chief complaint. The incidence among the elderly is estimated to be about 8%.

Causes and symptoms

The most common cause of BPV is head trauma (21% of cases) with a secondary concussion. The force of head trauma is thought to displace otolith particles in the semicircular canal. Approximately 39% of cases do not have a cause (idiopathic), and 29% of patients with BPV usually present with an existing ear disease. Other common causes include alcoholism, central nervous system (CNS) disease (approximately 11%), major surgery, and chronic ear infections such as chronic otitis media (approximately 9% of cases).

The severity of cases varies. Some patients may experience nausea and vomiting even with the slightest head movement, whereas some patients may be minimally bothered by the dizziness. As the name implies, symptoms of BPV are typically dependent on head position. Head movement, rolling in bed, leaning forward or backward, or changing posture can cause an attack. The symptoms start abruptly and disappear with 20–30 seconds.

Diagnosis

In addition to a detailed history, the physical examination is important for detection of characteristic physical signs such as nystagmus (involuntary rhythmic oscillation of the eyes). The examination is also necessary to exclude other neurological diseases that may mimic benign positional vertigo. A physician familiar with the condition may perform the Hallpike test. Also, in patients with vertigo, hearing tests are generally necessary. Further testing may be necessary to evaluation other conditions that can cause vertigo or dizziness.

Treatment team

The treatment team can consist of an emergency room physician, ear, nose, and throat (ENT) specialist-surgeon, neurologist, and audiologist. A primary care practitioner can initiate symptomatic management. Patients typically require follow-up care and monitoring. Surgical candidates require specialty care from an ENT surgeon, as well as and a surgical team in a hospital that is equipped for such an intervention.