Benign Paroxysmal Positional Vertigo (BPPV)
Benign paroxysmal positional vertigo (BPPV) is a mechanical disorder of the semicircular canals of the inner ear. There are three of these canals in each ear, along with two sensors that are able to sense gravity because they are capped by a bed of relatively heavy crystals. All of the canals and the gravity sensors are interconnected by fluid pathways, so if crystals become dislodged, they can migrate into other parts of the ear. BPPV arises when some of these crystals enter a semicircular canal. The openings to the semicircular canals lie just above the gravity sensors when a person is upright, but when lying down flat on the back facing the ceiling, the openings are located just below the sensors, allowing gravity and side-to-side rolling movements of the body to accidentally shift the particles into the canals. The semicircular canals are only capable of sensing turning motions, so the presence of particles moved by gravity causes tilting motions of the head to be incorrectly sensed as violent spinning.
Symptoms usually first come on while in bed. Rolling over in bed to one side can cause a very sudden, strong sensation of head-over-heels whirling that lasts for several seconds and then dies away. If the eyes are open the room can appear to spin violently. Attempting to sit up from lying down, to lie down from sitting, or to roll over while lying down can cause the symptoms to recur. After getting out of bed, symptoms can be brought on by tipping the head upward (while shampooing or reaching up toward a high shelf, for example), looking back over one shoulder, or by bending over forward and then lifting the head quickly. In people who are sensitive to motion sickness, there can be vomiting and prolonged, less severe dizziness in between positional spells. Older people may notice their balance is affected in between spells.
The dizzy spells end when the displaced particles leave the semicircular canal, which can happen spontaneously within a couple of hours, or can be delayed for many years. Certain movements can help to roll the particles back out of the semicircular canals. These therapeutic maneuvers can be performed by a trained health care worker, or can be done as a home exercise. However, the maneuvers cause the dizziness to recur, so some people are not able to do them without assistance.
The particles are usually located in the posterior/inferior semicircular canal, but can accidentally enter the other canals during maneuvers. The horizontal/lateral semicircular canal is particularly sensitive to these particles, often causing prolonged vomiting when particles enter. A sudden change in the vertigo while doing maneuvers to a horizontal spinning of the environment can indicate this complication, which requires a different treatment maneuver.
The diagnosis can be made by having the patient lie down quickly from the seated position, with the head turned 45 degrees to one side. This will cause vertigo with a lag of a few seconds,that lasts for less than one minute. This Dix-Hallpike test is used to diagnose which ear is involved; when the dizziness occurs when the right ear is down (the head turned 45 degrees to the right), it usually indicates that the right ear is affected. Treatment maneuvers are begun from this reclining position. The Epley maneuver involves rolling the patient to the opposite shoulder, followed by sitting up. The Semont maneuver requires the patient to sit up facing the side of the bed immediately after the Dix Hallpike, and then lie down on the opposite shoulder in the face-down position. Both are highly effective in removing particles from the semicircular canals. To reduce the risk of horizontal canal BPPV, it is important to wait at least 15 minutes between maneuvers. If the crystals accidentally enter the horizontal canal, usually while doing maneuvers or rolling over in bed, they can be removed by a Gufoni maneuver, in which the person sits up after the Dix Hallpike similar to the Semont maneuver, reclines on the side opposite to the affected ear, then slowly rotates the head to face the bed. The success rate with these maneuvers exceeds 90% in trained hands.
Some patients are able to do these maneuvers at home to treat themselves. There are simplified maneuvers that are very effective as home exercises. It is necessary to set off a dizzy spell in order to use the treatments, so if nausea is severe, it may be necessary to seek the assistance of a trained therapist or physician. The Half Somersault is a simple maneuver that is less likely to cause horizontal canal BPPV than the other maneuvers and causes less dizziness.
Because displaced particles remain permanently loose in the inner ear, it is possible to set off a recurrence when they re-enter a semicircular canal. This can happen days, months, or years after the first spell and may require another series of maneuvers for treatment. In rare cases, the treatments fail to remove particles completely, or recurrences happen on a very frequent basis. There are surgeries to plug or disable the affected semicircular canal in these rare cases.
Author: Dr. Carol Foster