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.
Treatment
There are three types of treatment given to patients with BPV: medical care, surgery, and home treatment. Medical care (office treatment) consists of either the Semont maneuver (also referred to as the Liberaroty maneuver) or the Epley maneuver, named after their inventors. The Semont maneuver (a series of head-turning exercises) involves a rapid shift from lying on one side to lying on the opposite side. The Epley maneuver involves sequentially moving the head in four different positions and waiting for 30 seconds on each turn. These maneuvers are effective in approximately 80% of patients who are diagnosed with BPV, although symptoms may reoccur after initial improvement in a substantial percentage of patients. If office medical treatment fails, patients can continue treatment at home with the Brandt-Daroff Exercises, which are difficult to perform, but effective in 95% of cases. These exercises are time consuming and done in three sets per day for two weeks. Medical treatment with medications is not recommended since they do not help relieve symptoms.
A surgical procedure called posterior canal plugging can be utilized in patients who had no response to any other form of treatment. With this procedure, there is a small risk of hearing deficit (usually less than 20%), but it is effective in most patients. The posterior semicircular canal is excised, exposing the membranous labyrinth with floating otoliths. The canal is patched off with tissue so otolith particles cannot move into the canal to stimulate the hair cells within this area. The canal is sealed and the incision sutured. Typically, the patient will stay in the hospital overnight and return one week later for suture removal.
Recovery and rehabilitation
Recovery and rehabilitation is favorable. Most patients recover well with head-tilting exercises. Patients who have recurrence of symptoms will undergo further exercises or surgical correction, which is successful for resolution of symptoms in more than 90% of surgical candidates.
Clinical trials
A large study is currently active concerning the treatment of BPV in family practice at McMaster University Department of Family Medicine in Hamilton, Ontario, Canada. Contact is Shawn Ling at (905) 521-2100 ext. 75451; fax: (905) 521-5010; e-mail: lingfpu@yahoo.ca. Clinical trials as of 2001 reported good results using the Epley canalith repositioning maneuver. In 86 patients studied, 70% had resolution of symptoms within two days after treatment.
Prognosis
The overall prognosis for patients who suffer from BPV is good. Spontaneous remission can occur within six weeks, but some cases never remit. Once treated, the recurrence rate is between 5% and 15%.
BOOKS
Goldman, Lee, et al. Cecil's Textbook of Medicine, 21st ed. Philadelphia: WB. Saunders Company, 2000.
PERIODICALS
Chang, Andrew K. "Benign Positional Vertigo." eMedicine Series (April 2002).
Haynes, D. S. "Treatment of Benign Positional Vertigo Using the Semont Maneuver: Efficacy in Patients Presenting without Nystagmus." Laryngoscope 112:5 (May 2002).
Li, John. "Benign Positional Vertigo." eMedicine Series (December 2001).
