Benign Paroxysmal Positional vertigo
Benign Paroxysmal Positional vertigo (BBPV) or ‘cupololithiasis’ is a common condition in which the individual experiences episodes of recurrent and brief postural vertigo and nystagmus (rhythmic rotation of the eyeballs) that tends to occur in clusters. The exact cause of the condition is not understood clearly, but the displaced remnants of the utricular otocania (which is a membranous structure present within the ear). The condition is also said to arise due to abnormalities in the posterior semicircular canal.
It may be provoked by altering the position of the head relative to gravity during lying down, rolling the head in the bed, bending, titling the head backwards, sleeping or sitting up. The episodes of vertigo usually last for about 10 to 30 seconds. BPPV can involve either the posterior semicircular canals or the lateral semicircular canals or both. The condition can occur on one side or on either side of the skull. A Posterior canal BPPV can be converted into a lateral BPPV following repositioning maneuvers. The episodes of vertigo may take a few months or even years to resolve.
The remission and recurrence is often considered to be unpredictable. BPPV is one of the most common disorders in which vertigo is experienced. The incidences may be about 17 % when a study was conducted in a vertigo clinic. In Japan, the occurrence of BPPV is about 10. 7 to 17. 3 per 100000 new cases every year. However, the actual incidence rates may be much higher as the condition can spontaneously resolve. The condition occurs more often in females compared to males. However, in younger individuals who often develop the condition following trauma, the male to female ratio is almost equal.
The condition more frequently occurs in middle aged and elderly individuals between the ages of 40 to 65 years. In a study conducted in the elderly population, it was observed that about 10 % had unrecognized BPPV. Today, BPPV is one of those conditions which can be promptly diagnosed using a specific diagnosis process and treated using advanced techniques. Physiology A lot of studies have been conducted to determine the exact mechanism by which BPPV. In the inner ear, a small organ known as ‘vestibular labyrinth’ is present. Within this, a small structure known as ‘semi-circular canals’ is present.
The semi-circular canals are nothing but loop-like structures, containing fluid and hair-like projections. They help to determine the movements of head in a three-dimensional direction. The Otolith also helps to determine the movement of the head relative to the body. In the otolith, certain crysltals of calcium carbonate are present. In certain conditions, these crystals may get dislodged into the semi-circular canals. When these crystals get dislodged, it makes the head very sensitive to positional changes. In conditions it is normally not required to respond, a dizziness-like sensation is perceived.
BPPV are of two types, primary or idiopathic and secondary. In primary BPPV, the cause is not known and it accounts for 50 to 70 % of the cases. Secondary BPPV account for 7 to 17 % of the cases and is usually associated with head trauma. When the head is traumatized, otoconia crystals are released into the endolymph. The otoconia crystals are actually calcium carbonate crystals that get embedded in the utricle and the saccule. This occurs bilaterally, resulting in BPPV occurring on both sides. Studies have demonstrated that in 0. 5 to 3. 1 % cases, BPPV is associated with Meniere’s disease.
Recently, it has been found that migraine is also closely associated with BPPV. Studies conducted on patients suffering from migraine when the patients were positioned in certain postures, BPPV tended to occur. The exact mechanism between migraine and BPPV is not known, but it is supposed to occur due to spasm of the inner ear. BPPV may also occur following surgery of the inner ear. Once the otoconia crystals get displaced, they begin to stimulate the hair cells present in the posterior semicircular canals. Once this promotion occurs, the individual constantly feels that he/she is in motion.
There may also be other etiological factors for BPPV including degeneration of the otoconia membranes, concussion of the labyrinthine, middle ear infection, viral infections of the ear (such as viral neuronitis), taking bed rest for long periods of time (lying supine for long time), blockage of the anterior vestibular artery, anesthesia administration, administration of certain drugs, etc. Symptoms The symptoms of BPPV usually occur following a period of latency during which the condition initiates, but the symptoms are not felt.
An individual suffering from BPPV would develop several symptoms including brief attacks of horizontal and/or vertical vertigo, dizziness, light-headedness, unsteadiness, a sense of loss of balance, blurring of vision which develops in association with the vertigo, nausea vomiting, etc. the vertigo is usually felt following rolling on the bed or extending the head backwards. The individual may develop the vertigo when moving the head towards the left or the right or both. Whichever side the vertigo develops, that particular side is involved in the vertigo process. The attacks of vertigo usually last for about half a minute or thirty seconds.
On repeated testing of vertigo symptoms, it usually diminishes. In some patients, this duration may get extended for about one minute. About 50 % of the patients suffering from BPPV experienced a kind of floating sensation. Following he vertigo sensations, the individual also experiences bouts of nausea and loss of static equilibrium. The frequency of the vertigo attacks vary from one individual to another, ranging from a several episodes in a day to a few episodes in a week or month. Some individuals may also be sensitive to movement of the head in any direction.
Along with the symptoms, the individuals may also develop several mental symptoms including anxiety, depression, cancer phobia, etc. In certain situations, the vertigo attacks may be life-threatening. Take for example a high-rise building construction worker, can put himself in danger of losing his life in case he develops a vertigo attack related to BPPV. Even driving whilst suffering from BPPV is a danger, as the visual field is impaired. The episodes of vertigo can in fact disappear during the course of the disease and suddenly recur. Abnormal eye movements (nystagmus) are also common in BPPV.
Serious complications arising from BPPV are rare. One of the potential complications includes dehydration due to constant vomiting which may develop from vertigo. Tinnitus and hearing loss are rarely associated with BPPV. Diagnosis The diagnosis of BPPV is made based on the history, symptoms, signs, physical examinations and diagnostic tests such as your electronystagmography (ENG), videonystagmography (VNG) and Magnetic resonance scans (MRIs). One of the commonest signs of BPPV is dizziness that occurs when the head or the eye is moved, that tends to occur for duration of up to one minute.
One of the diagnostic examination procedures utilized to determine BPPV is Dix-Hallpike maneuver. It is utilized especially to diagnose posterior BPPV. The patient is made to sit upright on the bed with the chin/head facing downwards. Then the patient is slowly moved backwards and is taken into a lying position on the bed, with the chin/head moved backwards. Once the patient is taken into this position, nystagmus develops after one to five seconds and lasts for about 30 seconds. The nystagmus has initially a light vertical component and then a strong torsion component.
When the patient is moved from the lying with head facing backwards, to the sitting position with the head bend downwards, then the two components of the nystagmus also beings to appear in reverse order. An associated sign with the nystagmus is vertigo which varies depending on the intensity of the nystagmus. The procedure should be repeated with the head facing the right side and the left side to determine the involvement of the posterior canal on either side. In order to determine for lateral BPPV, the patient is made to lie supine on the bed with head upright.
Then the head and the entire body are turned to the suspected side of involvement quickly. A nystagmus appears which is horizontal in nature which has very short latency periods and becomes more and more oblivious when the test posture is maintained. The individual may get fatigued when kept in the lateral position for a long time. In some patients, the Dix-Hallpike maneuver may be positive, but may not in fact experience the symptoms of vertigo. These patients need to be tested again by repositioning. Electronystagmography and videonystagmography is utilized to determine the abnormal eye movements.
ENG is enabled by using electrodes whereas VNG is enabled using cameras. The individual may feel dizziness during certain maneuvers, and this is studied using ENG and VNG. MRI scans are basically done to determine any brain tumor or lesion present within the skull that could be causing dizziness and vertigo. Gadolinium-enhanced MRI scans can help to determine of any lesion within the skull more closely. Several other conditions such as labyrinthitis, vestibular neuronitis, Meniere’s disease, etc, need to be ruled out through the process of differential diagnosis. Treatment
BPPV can remit spontaneously within a few months or weeks without any treatment. Drug treatment is usually not recommended, as the symptoms can reduce only temporarily and it offers no permanent solution for the condition. In some individual, the adverse affects of certain drugs may worsen the vertigo. One measure that can be applied in order to treat vertigo is exercises or provocative maneuvers. The individual needs to perform certain exercises in the morning which would cause fatigue and ensure that the symptoms for the remaining portion of the day are within control.
Surgery and the canalith repositioning procedure (CRP) seem to the most effective forms of treatment for the condition BPPV. In the CRP procedure, the physician or the audiologist would be performing a series of maneuvers in order to reposition the canalith into the utricle. In the Epley’s maneuver, the patient is sedated and mechanical skill vibration is utilized to move the head into 5 different positions. The otolith debris would then be influenced by gravity and would move from their position in the semicircular canals into the utricle. The particle repositioning procedure is done by using a 3 stage maneuver.
The physician or the audiologist should have a clear understanding of ear anatomy and the mechanism in which BPPV occurs. The prolonged position maneuver is utilized to treat BPPV that arises due to involvement of the lateral canals. Studies conducted by Blakley (1994) demonstrated that there were no significant changes in the outcome when the patient was treated with CRP or with nothing. This is because the brain may adapt to the vertigo. Surgery is usually recommended if the BPPV does not respond to maneuvers nor has a multiple recurrence rates.
Singular neurectomy involves sectioning the ampullary nerve that transmits nerve signals from the posterior semicircular canals to the brain. However, there are also chances that the patient could become deaf. Posterior semicircular canal occlusion involves causing blockage of the semicircular canal lumen in order to prevent endolymph from flowing. When the individual performs any movement, the cupula does not respond. References: Epley, J. M. (1992). “The Canalith repositioning procedure: For treatment of benign paroxysmal positional vertigo. ” Otolaryngology – Head and Neck Surgery, 107(3).
Gordon, C. R. Et al (2004). “Repeated vs single physical maneuver in benign paroxysmal positional vertigo. ” Acta Neurol Scand, 110, 166–169. Mayo Clinic Staff (2008). Benign paroxysmal positional vertigo (BPPV) – Introduction, Retrieved on June 3, 2008, from Mayo Clinic Web site: http://www. mayoclinic. com/health/vertigo/DS00534/DSECTION=1 Oghalai, J. S. (2007). Benign Paroxysmal Positional Vertigo, Retrieved on June 3, 2008, from The Merck Manual Web site: http://www. merck. com/mmpe/sec08/ch086/ch086c. html# Parnes, L. S. , Agarwal, S. K. , & Atlas, J. (2003).
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