Benign paroxysmal positional vertigo
Benign paroxysmal positional vertigo is a disorder arising from a problem in the inner ear. Symptoms are repeated, brief periods of vertigo with movement, characterized by a spinning sensation upon changes in the position of the head. This can occur with turning in bed or changing position. Each episode of vertigo typically lasts less than one minute. Nausea is commonly associated. BPPV is one of the most common causes of vertigo.
BPPV is a type of balance disorder along with labyrinthitis and Ménière's disease. It can result from a head injury or simply occur among those who are older. Often, a specific cause is not identified. When found, the underlying mechanism typically involves a small calcified otolith moving around loose in the inner ear. Diagnosis is typically made when the Dix–Hallpike test results in nystagmus and other possible causes have been ruled out. In typical cases, medical imaging is not needed.
BPPV is easily treated with a number of simple movements such as the Epley maneuver or [|half somersault maneuver], the Lempert maneuver, the deep head hanging maneuver or the Brandt–Daroff exercises. Medications, including antihistamines such as meclizine, may be used to help with nausea. There is tentative evidence that betahistine may help with vertigo, but its use is not generally needed. BPPV is not a serious medical condition, but may present serious risks of injury through falling or other spatial disorientation-induced accidents.
When untreated, it might resolve in days to months; however, it may recur in some people. One can needlessly suffer from BPPV for years despite there being a simple and very effective cure. Short-term self-resolution of BPPV is unlikely because the effective cure maneuvers induce strong vertigo which the patient will naturally resist and not accidentally perform.
The first medical description of the condition occurred in 1921 by Róbert Bárány. Approximately 2.4% of people are affected at some point in time. Among those who live until their 80s, 10% have been affected. BPPV affects females twice as often as males. Onset is typically in people between the ages of 50 and 70.
Signs and symptoms
According to the Barany Society's , the diagnostic criteria for BPPV include- Recurrent attacks of positional vertigo or dizziness provoked by changes in position.
- Characteristic positional nystagmus elicited by each maneuver, according to the subtype and affected ear.
The spinning sensation experienced from BPPV is usually triggered by movement of the head, will have a sudden onset, and can last anywhere from a few seconds to several minutes. The most common movements people report triggering a spinning sensation are tilting their heads upward in order to look at something and when rolling over in bed.
People with BPPV do not experience other neurological deficits such as numbness or weakness. If those symptoms are present, a more serious etiology, such as posterior circulation stroke or ischemia, must be considered.
The most significant symptom is nystagmus as it is essential to determine the kind of nystagmus to select the correct cure maneuver.
Cause
Within the labyrinth of the inner ear lie collections of calcium crystals known as otoconia or otoliths. In people with BPPV, the otoconia are dislodged from their usual position within the utricle, and over time, migrate into one of the three semicircular canals. When the head is reoriented relative to gravity, the gravity-dependent movement of the heavier otoconial debris within the affected semicircular canal causes abnormal endolymph fluid displacement and a resultant sensation of vertigo. This more common condition is known as canalithiasis. There is a direct link between the kind of nystagmus and which of the three semicircular canals is affected. With horizontal nystagmus the horizontal canal is affected, with vertical nystagmus the superior canal is affected, and with diagonal nystagmus the posterior canal is affected. Diagonal eye movement is easily confused with horizontal movement. This is important since it might result in selecting a wrong and thus ineffective cure maneuver.In rare cases, the crystals themselves can adhere to a semicircular canal cupula, rendering it heavier than the surrounding endolymph. Upon reorientation of the head relative to gravity, the cupula is weighted down by the dense particles, thereby inducing an immediate and sustained excitation of semicircular canal afferent nerves. This condition is termed cupulolithiasis.
There is evidence in the dental literature that malleting of an osteotome during closed sinus floor elevation, otherwise known as osteotome sinus elevation or lift, transmits percussive and vibratory forces capable of detaching otoliths from their normal location and thereby leading to the symptoms of BPPV.
BPPV can be triggered by any action that stimulates the posterior semi-circular canal including:
- Looking up or down
- Following head injury
- Sudden head movement
- Rolling over in bed
- Tilting the head
- Changes in barometric pressure – people may feel increased symptoms up to two days before rain or snow
- Lack of sleep
- Stress
BPPV is one of the most common vestibular disorders in people presenting with dizziness; a migraine is implicated in idiopathic cases. Proposed mechanisms linking the two are genetic factors and vascular damage to the labyrinth.
Although BPPV can occur at any age, it is most often seen in people older than the age of 60. Besides aging, there are no major risk factors known for BPPV, although previous episodes of head trauma, preexisting disorders, or the inner ear infection labyrinthitis, may predispose to the future development of BPPV.
Mechanism
The inside of the ear is composed of an organ called the vestibular labyrinth. The vestibular labyrinth includes three semicircular canals, which contain fluids and fine hairlike sensors that act as a monitor to the rotations of the head. Other important structures in the inner ear includes the otolith organs, the utricle and saccule, that contain calcium carbonate crystals that are sensitive to gravity.The crystals may dislodge from the utricle and settle within the semicircular canals. When there is motion, the displaced otoconia shift within the endolymph of semicircular canals, causing an unbalanced stimulus, causing symptoms of BPPV.
Diagnosis
The condition is diagnosed by the person's history, and by performing the Dix–Hallpike test or the roll test, or both. The patient can also be asked to induce vertigo by performing a movement that the patient knows to induce vertigo. The eyes of the patient can then easily be observed for which kind of nystagmus is present, to determine which semicircular canal is affected.The Dix–Hallpike test is a common test performed by examiners to determine whether the posterior semicircular canal is involved. It involves a reorientation of the head to align the posterior semicircular canal with the direction of gravity. This test will reproduce vertigo and nystagmus characteristic of posterior canal BPPV.
When performing the Dix–Hallpike test, people are lowered quickly to a supine position, with the neck extended by the person performing the maneuver. For some people, this maneuver may not be indicated, and a modification may be needed that also targets the posterior semicircular canal. Such people include those who are too anxious about eliciting the uncomfortable symptoms of vertigo, and those who may not have the range of motion necessary to comfortably be in a supine position. The modification involves the person moving from a seated position to side-lying without their head extending off the examination table, such as with Dix–Hallpike. The head is rotated 45 degrees away from the side being tested, and the eyes are examined for nystagmus. A positive test is indicated by the patient report of a reproduction of vertigo and clinician observation of nystagmus. Both the Dix–Hallpike and the side-lying testing position have yielded similar results, and as such the side-lying position can be used if the Dix–Hallpike cannot be performed easily.
The roll test can determine whether the horizontal semicircular canal is involved. The roll test requires the person to be in a supine position with their head in 30° of cervical flexion. Then the examiner quickly rotates the head 90° to the left side, and checks for vertigo and nystagmus. This is followed by gently bringing the head back to the starting position. The examiner then quickly rotates the head 90° to the right side and checks again for vertigo and nystagmus. In this roll test, the person may experience vertigo and nystagmus on both sides, but rotating toward the affected side will trigger a more intense vertigo. Similarly, when the head is rotated toward the affected side, the nystagmus will beat toward the ground and be more intense.
As mentioned above, both the Dix–Hallpike and roll test provoke the signs and symptoms in subjects with archetypal BPPV. The signs and symptoms people with BPPV experience are typically a short-lived vertigo and observed nystagmus. In some people, although rarely, vertigo can persist for years. Assessment of BPPV is best done by a medical health professional skilled in the management of dizziness disorders, commonly a physiotherapist, audiologist, or other physician.
The nystagmus associated with BPPV has several important characteristics that differentiate it from other types of nystagmus.
- Latency of onset: there is a 5–10 second delay prior to onset of nystagmus
- Nystagmus lasts for 5–60 seconds
- Positional: the nystagmus occurs only in certain positions
- Repeated stimulation, including via Dix–Hallpike maneuvers, cause the nystagmus to fatigue or disappear temporarily
- Rotatory/torsional component is present, or the nystagmus beats in either a geotropic or ageotropic fashion
- Visual fixation suppresses nystagmus due to BPPV