8 Benign Paroxysmal Positional Vertigo Benign paroxysmal positional vertigo (BPPV) is a commonly recognized vestibular disorder. Earlier estimates of the incidence of BPPV range from 10.71 to 642 per 100,000, with increases of 38% with each decade of life, but later data suggest that the disorder may be more common. In a 2000 study, Oghalai et al noted that 9% of randomly selected geriatric patients in an urban clinic who had undergone positional testing had positive results and undiagnosed BPPV.3 In 1952, Dix and Hallpike described the characteristic ipsidirectional torsional nystagmus provoked by the head maneuver they developed to identify BPPV.4 During this maneuver, the patient’s head is turned 45° to one side while he or she is seated. The patient is then moved quickly to a supine position with the neck slightly extended and the head remaining turned. When the lower ear is affected, nystagmus is seen. The patient is then brought back up to a sitting position, and the nystagmus is noted to reverse direction. The maneuver is then performed on the other side. The characteristic nystagmus occurs after a delay of several seconds, declines after 10 to 30 seconds, and diminishes with repeated positional testing in the same sitting.4,5 Although the maneuver needs no special equipment, visualization of the nystagmus can be aided by the use of infrared video or optical Frenzel lenses, which eliminate visual fixation. Approximately 94% of BPPV cases involve the posterior semicircular canal.6 Lateral (horizontal) semicircular canal (LSC) involvement is the next most common. Lateral semicircular canal benign paroxysmal positional vertigo (LSC-BPPV) was first described by Cipparrone et al7 and McClure8 in 1985, and is characterized by nystagmus provoked by supine bilateral head turns and beating toward the lower ear. There are now known to be two distinct subtypes of LSCBPPV based on the direction of horizontal nystagmus during supine head turns: geotropic and apogeotropic. Geotropic LSC-BPPV beats toward the lower ear on supine positional testing and is characterized by short latency and prolonged duration of horizontal nystagmus with poor fatigability. Apogeotropic LSCBPPV, thought to be more rare, was not reported until later by Pagnini et al9 and Baloh et al (Video 8.1).10 Apogeotropic LSC-BPPV is characterized by similar short-latency and prolonged-duration horizontal nystagmus, but the direction beats away from the lower ear on supine positional testing (Video 8.2). Geotropic LSC-BPPV is thought to be caused by otoconial debris moving under the influence of gravity within the long arm of the LSC stimulating utriculopetal endolymph flow in the supine position with the affected ear down (Fig. 8.1). Different factors are likely responsible for apogeotropic LSC-BPPV, including otoconial debris that adheres to the cupula of the LSC, causing the cupula to become gravity sensitive (cupulolithiasis), and otoconia trapped in the proximal segment of the LSC near the cupula (Fig. 8.2).7,8,9,10,11,12 Posterior semicircular canal (PSC) BPPV is likely caused by otoconia that detach from the utricle and fall into the PSC (canaliths). Schuknecht13 was the first to suggest that these basophilic deposits on the cupula of the PSC are the cause of BPPV. However, further work and intraoperative observations suggest that they are likely to be free-floating in the PSC, where they act as a plunger, rendering the canal gravitationally sensitive (Video 8.3 and Video 8.4).14,15 Benign paroxysmal positional vertigo is usually idiopathic but can occur after head trauma or in association with other ear disorders, such as vestibular neuritis or labyrinthitis.16,17,18,19 Certain positions are likely to provoke vertigo, including lying back in bed, arising quickly, looking up, or reclining for dental or hairdressing procedures. Fig. 8.1 Geotropic lateral semicircular canal benign paroxysmal positional vertigo affecting the left ear. Used with permission from White J. Benign paroxysmal positional vertigo: how to diagnose and quickly treat it. Cleve Clin J Med 2004;71(9):722–728. Fig. 8.2 Apogeotropic lateral semicircular canal benign paroxysmal positional vertigo affecting the left ear. Used with permission from White J. Benign paroxysmal positional vertigo: how to diagnose and quickly treat it. Cleve Clin J Med 2004;71(9):722–728. Initially, BPPV treatments were exercise based and emphasized compensation and habituation.20,21 Vestibular suppressant medication is not as effective as exercise treatments.22,23 Specific canalith repositioning maneuvers based on an improved understanding of the pathophysiology of BPPV have been developed in the past 15 years and are now the standard of treatment. These maneuvers include the Semont,24 the Epley,25 and the particle repositioning maneuvers15 for PSC-BPPV, the last of which is a modified Epley maneuver without mastoid vibration. A commonly used term for the modified Epley maneuver is canalith repositioning maneuver (Fig. 8.3) (Video 8.5). Identification of the involved canal is necessary before appropriate maneuvers can be chosen. Although Dix-Hallpike positioning is highly sensitive to PSCBPPV, it lacks sensitivity in LSC-BPPV (Video 8.6). For this reason, positional/positioning testing should include Dix-Hallpike positioning to head-hanging right and left positions and supine positional testing in the head-centered supine, right ear down, and left ear down positions. Dix-Hallpike was entirely negative in two published patients whose horizontal nystagmus with lateral supine head turns reached 12 deg/s and 16 deg/s.26 In most of the other patients with LSC-BPPV, the Dix-Hallpike positioning nystagmus had a lesser velocity than that seen on supine positional testing. My preference is to perform the head-centered supine and supine left and right ear down positions before returning the patient to sit, and next performing the Dix-Hallpike maneuvers, to increase sensitivity and diagnostic accuracy for LSC-BPPV. Fig. 8.3 Canalith repositioning maneuver for right posterior semicircular canal benign paroxysmal positional vertigo. Used with permission from White J. Benign paroxysmal positional vertigo: how to diagnose and quickly treat it. Cleve Clin J Med 2004;71(9):722–728. The identification of the involved ear in LSCBPPV can be especially difficult because the canals are coplanar, and nystagmus is seen in both lateral supine positions. Order effect and head tilt may affect the direction of nystagmus.27 In geotropic LSCBPPV, the nystagmus is worse with the affected ear down. Treatment for geotropic horizontal semicircular canal-benign paroxysmal positional vertigo (HSC-BPPV) consists of 360° roll maneuvers toward the unaffected ear, beginning with the patient in the supine position with the head flexed 0° to 30° and laterally rotated toward the affected ear, and proceeding in 90° increments every 30 to 60 seconds toward the unaffected ear.28 The Gufoni maneuver is also highly effective and is performed with the patient beginning in the sitting position and lying quickly to the unaffected side and then rotating the head 45° downward, maintaining the position for 2 to 3 minutes as described in Appiani et al.12 Treatment for apogeotropic LSC-BPPV consists of a variety of maneuvers because none is universally effective. Identification of the affected ear can be more challenging in apogeotropic LSC-BPPV. Nystagmus is usually worse with the affected ear up, and nystagmus is occasionally seen in the sitting or supine position that usually beats toward the involved side.29 The Lempert 360° roll maneuver toward the unaffected ear may be used first. The modified Gufoni maneuver can be performed with the patient beginning in the sitting position and lying quickly to the affected side and then rotating the head 45° upward, maintaining the position for 2 to 3 minutes, as described by Appiani et al.12 The Vannucchi-Asprella maneuvers are performed with the patient rapidly moving from the sitting to the supine position then turning the head rapidly to the unaffected side and returning to sitting, where the head is then returned to midline. This maneuver is repeated five to eight times in rapid succession.30 Anterior semicircular canal BPPV is a controversial entity. Some investigators suggest the paroxysmal nystagmus has a pure or torsional downbeat component, in contrast to the nystagmus with PSC-BPPV, which has a vertical upbeat component. Because the same maneuvers used to treat PSC-BPPV appear effective for possible anterior canal involvement (although they may be performed on the contralateral side in some reports), the question may have more theoretical than clinical relevance. A patient’s response to treatment is assessed using self-reported vertigo frequency and severity and with objective assessment using repeated Dix-Hall-pike testing. Several authors have noted a poor correlation between self-report and Dix-Hallpike testing results. For example, Pollack et al,31 Dornhoffer and Colvin,32 and Ruckenstein33 found that 22 to 38% of patients continue to report symptoms despite negative Dix-Hallpike testing, whereas Sargent et al34 noted reports of subjective improvement despite persistent positive Dix-Hallpike results in his study sample. Lynn et al35 suggested that objective DixHallpike testing should be considered the gold standard of outcome measures in BPPV. Controlled trials performed without Dix-Hallpike testing at outcome36 are generally excluded from evidence-based reviews. The impact of canalith repositioning on the quality of life in patients with BPPV has been demonstrated using the Medical Outcomes Study 36-item Short Form (SF-36)37 and the Dizziness Handicap Inventory Short Form (DHI-S).38 In one study, patients with active BPPV scored worse than population norms on both measures, which improved 1 month after canalith repositioning maneuvers were performed (DHI-S mean decrease 8.1, p < 0.001, n = 40).39 In addition, SF-36 subscales normalized (p < 0.05).40 Benign paroxysmal positional vertigo is believed to be self-limiting, although Baloh and Honrubia reported symptoms that persisted for more than 1 year in one-third of their 240 patients with BPPV.41 The inclusion of a randomized control group allows the spontaneous rate of remission to be compared with the effect of canalith repositioning. Recurrence is common after successful canalith repositioning for BPPV. Treatment is commonly effective in eliminating the current episode but does not prevent additional episodes. Although the average recurrence rate is ~ 15% per year,25,42,43 reported rates have ranged from 5% per year44 to 45% at 30 weeks.45 Conversion between canals can occasionally occur, usually between posterior and horizontal canals when the patient is retested with Dix-Hallpike positioning after canalith repositioning has been performed (Fig. 8.4). It is heralded by the development of brisk horizontal nystagmus and responds well to a 360° supine roll maneuver toward the good side. Patients were usually advised to keep their head elevated for 24 to 48 hours after the positioning procedure and to avoid lying on the affected side for 5 days, all of which theoretically allows the free-floating canalith debris to settle back into the utricle rather than return to the semicircular canal. Several studies have suggested that these instructions do not increase treatment efficacy.46,47,48 Massoud and Ireland47 studied outcomes for the particle repositioning maneuver (n = 46) in patients who were randomized to postprocedure restrictions or control, with follow-up at 1 week. Ninety-six percent of the 23 patients in the control group resolved their BPPV, compared with 88% of the patients who received postprocedure restrictions. The difference did not reach statistical significance, possibly due to the small sample size. Numerous centers continue to observe postprocedure restrictions based on anecdotal experience.
Introduction
Treatment
Treatment Maneuvers
Treatment Efficacy
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