Benign paroxysmal positional vertigo (BPPV) is a disorder caused by problems in the inner ear. Its symptoms are repeated episodes of positional vertigo, that is, of a spinning sensation caused by changes in the position of the head.
Vertigo, also called dizziness, accounts for about 6 million clinic visits in the U.S. every year, and 17–42% of these patients eventually are diagnosed with BPPV.
Signs and symptoms
- Vertigo: Spinning dizziness, which must have a rotational component.
- Short duration (Paroxysmal): Lasts only seconds to minutes
- Positional in onset: Can only be induced by a change in position.
- Nausea is often associated
- Visual disturbance: It may be difficult to read or see during an attack due to the associated nystagmus.
- Pre-Syncope (feeling faint) or Syncope (fainting) is unusual.
- Emesis (Vomiting) is uncommon but possible.
- Rotatory (torsional) nystagmus, where the top of the eye rotates towards the affected ear in a beating or twitching fashion, which has a latency and can be fatigued (if you repeatedly continue placing yourself in the position to cause vertigo the symptoms should lessen each time).
Within the labyrinth of the inner ear lie collections of calcium crystals known as otoconia. In patients with BPPV, the otoconia are dislodged from their usual position within the utricle and they migrate over time into one of the semicircular canals (the posterior canal is most commonly affected due to its anatomical position). When the head is reoriented relative to gravity, the gravity-dependent movement of the heavier otoconial debris (colloquially "ear rocks") within the affected semicircular canal causes abnormal (pathological) fluid endolymph displacement and a resultant sensation of vertigo. This more common condition is known as canalithiasis.
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 maintained 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 enough percussive and vibratory forces capable of detaching otoliths from their normal location and leading to the symptoms of BPPV.
It can be triggered by any action which stimulates the posterior semi-circular canal which may be:
- Tilting the head
- Rolling over in bed
- Looking up or under
- Sudden head motion
- Post head injury
BPPV may be made worse by any number of modifiers which may vary between individuals:
- Changes in barometric pressure - patients often feel symptoms approximately two days before rain or snow
- Lack of sleep (required amount of sleep may vary widely)
BPPV is one of the most common vestibular disorders in patients presenting with dizziness and migraine is implicated in idiopathic cases. Proposed mechanisms linking the two are genetic factors and vascular damage to the labyrinth.
The condition is diagnosed from patient history (feeling of vertigo with sudden changes in positions); and by performing the Dix-Hallpike maneuver which is diagnostic for the condition. The test involves a reorientation of the head to align the posterior canal (at its entrance to the ampulla) with the direction of gravity. This test stimulus is effective in provoking the symptoms in subjects suffering from archetypal BPPV. These symptoms are typically a short lived vertigo, and observed nystagmus. In some patients, though rarely, the vertigo can persist for years. Assessment of BPPV is best done by a health professional skilled in management of dizziness disorders, commonly a physiotherapist, audiologist or other medical physician.
The nystagmus associated with BPPV has several important characteristics which differentiate it from other types of nystagmus.
- Positional: the nystagmus occurs only in certain positions
- Latency of onsent: there is a 5-10 second delay prior to onset of nystagmus
- Nystagmus lasts for 5–120 seconds
- Visual fixation does not suppress nystagmus due to BPPV
- Rotatory/Torsional component is present or (in the case of lateral canal involvement)the nystagmus beats in either a geotropic (towards the ground)or ageotropic (away from the ground) fashion
- Repeated stimulation, including via Dix-Hallpike maneuvers, cause the nystagmus to fatigue or disappear temporarily.
Two treatments have been found effective for relieving symptoms of posterior canal BPPV: the canalith repositioning procedure (CRP) or Epley maneuver, and the liberatory or Semont maneuver. The CRP employs gravity to move the calcium build-up that causes the condition. The particle repositioning maneuver can be performed during a clinic visit by health professionals or taught to patients to practice at home. In the Semont maneuver, patients themselves are able to achieve canalith repositioning. Only limited data are available comparing the two treatments, and it is not known which is more effective.
The Epley maneuver (particle repositioning) does not address the actual presence of the particles (otoconia), rather it changes their location. The maneuver aims to move these particles from areas in the inner ear which cause symptoms, such as vertigo, and repositions them to where they do not cause these problems.
Medical treatment with anti-vertigo medications may be considered in acute, severe exacerbation of BPPV, but in most cases are not indicated. These primarily include drugs of the anti-histamine and anti-cholinergic class, such as meclozine and scopolamine respectively. These offer symptomatic treatment, and do not affect the disease process or resolution rate. Medications may be used to suppress symptoms during the positioning manoeuvres if the patient has severe symptoms and may be unable to tolerate them.
Surgical treatments, such as a semi-circular canal occlusion, do exist for BPPV but carry the same risk as any neurosurgical procedure. Surgery is reserved as a last resort option for severe and persistent cases which fail vestibular rehabilitation (including particle repositioning and habituation therapy).