PATHOPHYSIOLOGY
BPPV most commonly is believed to result from calcium carbonate and protein crystals called otoconia becoming dislodged from the inner ear (utricle) and settling in one of the semicircular canals (most commonly the posterior); this theory is known as canalithiasis.18 When the patient moves certain ways, the otoconia shift and cause an abnormal stimulation of the motion sensor in the affected ear. This stimulation causes conflicting signals from the two labyrinths of the inner ear, resulting in brief, intense sensations of vertigo.18 A video describing the pathophysiology is available at www.youtube.com/watch?v=gDOrltSBvKI.
PATIENT PRESENTATION AND HISTORY
The patient’s description of symptoms is critical in the work-up for dizziness. It is important to ask patients to describe their symptoms using words other than “dizzy,” as the meaning of the word may vary from person to person.10
Dizziness includes a variety of symptoms such as vertigo, unsteadiness, weakness, presyncope, syncope, lightheadedness, or falling. Vertigo is the illusion of a rotational movement of one’s self or surroundings, a spinning sensation.19 True vertigo is most likely due to peripheral vestibular disorders. Complaints of disequilibrium and ataxia point to central pathology.2 Nonvertigo symptoms—generalized weakness, lightheadedness, imbalance, unsteadiness, and tilting sensations—can point to CNS, cardiovascular, and systemic diseases and require further investigation.4,10,18
A complete health history, including medications and assessing for head trauma, ear disease, or surgery, can be helpful in rendering a diagnosis. Patients should also be questioned about caffeine, nicotine, and alcohol use. A patient-centered questionnaire can be developed to guide the clinician in obtaining a thorough history of the patient’s perceptions of his/her symptoms. An important question to ask is, “Do you get dizzy when rolling over in bed?” A “yes” answer to this question raises the clinical suspicion for BPPV.
A typical description of BPPV symptoms includes a brief episode (less than a minute) of intense vertigo that can be brought about by positional changes associated with everyday activities such as rolling over in bed, tilting the head to look upward (eg, to place an object on a shelf higher than the head), or bending forward at the waist (eg, to tie shoes).4,18 This vertigo may occur frequently for weeks, disappear for months, and then begin again. Some patients may report that they were dizzy for hours or all day. On further questioning, however, the clinician may determine that the dizziness actually occurred in short, intense episodes,which, due to their severity, may be perceived as lasting longer than a minute.18 Commonly, patients may report periods of feeling imbalanced between BPPV episodes.4 Patients will sometimes report avoiding or modifying movements that commonly provoke symptoms in order to prevent an episode of vertigo.
Although the patient’s history can persuade the examiner to diagnose BPPV in a majority of cases, the AAOHNS guidelines state that history alone is insufficient to render an accurate diagnosis of BPPV.4
PHYSICAL EXAMINATION
The extent and focus of the physical examination is based on the patient’s history and symptoms. The goal of the exam is to reproduce the symptoms and to determine whether the patient has a benign cause of vertigo. Vital signs should always be obtained. A full head and neck exam should be performed to evaluate the ears, nose, and throat, since BPPV can occur secondary to other inner ear disorders.6 A complete neurologic exam should be done to assess for abnormalities in gait, coordination, and sensation. A thorough cardiovascular exam should be done to assess for carotid bruits and abnormal heart rate or rhythm. A carotid doppler, electrocardiogram, or Holter monitoring should be ordered only if abnormalities are found on the exam and/or there is a strong clinical suspicion of a cardiac cause based on the patient’s symptom history.20
The Dix-Hallpike maneuver should be performed in patients with vertigo to assess for posterior semicircular canal BPPV (see “Performing the Dix-Hallpike maneuver”).5 Although positive results from the Dix-Hallpike are the gold standard for diagnosing BPPV, negative results do not rule out BPPV since the patient may be asymptomatic on the day of the test.4,18 In patients with significant vascular disease, cervical stenosis and radiculopathies, severe kyphoscoliosis, Down syndrome, spinal cord injuries, low back dysfunction, ankylosing spondylitis, or morbid obesity, the Dix-Hallpike maneuver should be performed with caution.4 Obese patients may require an additional examiner for support.
If a positive response is observed on the initial side, no further testing is required; the examiner should immediately begin treatment with the canalith repositioning maneuver (described in the Treatment section). When the test response is negative, however, the maneuver should be repeated on the opposite side to confirm which ear is involved. Rarely is a response elicited in both the right and left ear-down positions with corresponding nystagmus; such a response is typically associated with head trauma.4
To rule out orthostatic hypotension, a possible source of “faintness” or “dizziness,” measure for changes in blood pressure (eg, decrease of 20 mm Hg systolic, decrease of 10 mm Hg diastolic) and pulse (eg, increase of 30 beats/min) from the supine to standing positions.20 These measurements should be performed after the Dix-Hallpike maneuver because the changes in patient position required to test BP may affect the results of the Dix-Hallpike maneuver. With the exception of positive results on the Dix-Hallpike test, the patient with BPPV will generally have unremarkable findings on the physical exam.3
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