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Benign paroxysmal positional vertigo with multiple canal involvement
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American Journal of Otolaryngology–Head and Neck Medicine and Surgery 33 (2012) 250 – 258 www.elsevier.com/locate/amjoto
Benign paroxysmal positional vertigo with multiple canal involvement Dimitrios G. Balatsouras, MD, PhD⁎ ENT Department, Tzanion General Hospital of Pireaus, Pireaus, Greece Received 16 March 2011
Abstract
Purpose: The aims of this study were to describe the frequency and clinical features of benign paroxysmal positional vertigo (BPPV) with multiple canal involvement and to evaluate the results of treatment by appropriate canalith repositioning procedures. Materials and Methods: A total of 345 patients were referred for BPPV between 2006 and 2010. Thirty-two of them (9.3%) who had BPPV of multiple canals were studied. Thirteen were men (mean age, 60.4 years) and 19 were women (mean age, 56.8 years). Dix-Hallpike and supine roll tests were performed for diagnosis. Canalith repositioning procedures for treatment included modified Epley, barbecue, Gufoni, and anterior BPPV-specific maneuvers. Results: Twenty-one patients had bilateral posterior canal BPPV, and 11 had mixed canal BPPV either on the same side (7 patients) or on both sides (4 patients). Thirty-one patients were cured with an average of 2.9 therapeutic sessions per patient. Recurrences occurred in 5 patients (15.6%). Conclusions: Benign paroxysmal positional vertigo of multiple canals is not rare and presents a clinical challenge. However, accurate diagnosis results in successful treatment comparable with BPPV of 1 canal. © 2012 Elsevier Inc. All rights reserved.
1. Introduction Benign paroxysmal positional vertigo (BPPV) is one of the most common clinical entities encountered in a neurotology clinic [1]. This disorder is associated with a characteristic paroxysmal positional nystagmus, which may be torsional, vertical, or horizontal, and is characterized by findings such as latency, crescendo and decrescendo, transience, reversibility, and fatiguability [2]. Although in most cases of BPPV the posterior canal is involved, BPPV of the horizontal canal occurs in a smaller rate, ranging from 5% to 30% according to various reports [3-4], and more rarely, involvement of the anterior canal may be observed [5]. Disease of multiple canals, either bilaterally or on the same side, represents a small fraction only of the patients with BPPV, but their presentation is quite interesting because of the various diagnostic and therapeutic challenges arising.
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In several studies [6-7], such cases have been occasionally reported, but the various pathogenetic and diagnostic issues need further discussion. The aim of this study is to present a series of patients with BPPV with multiple canal involvement diagnosed and treated in the Neurotology Unit of an Otolaryngology department during the last 5 years. I intended also to present an in-depth discussion of the nystagmus characteristics, which should be useful in differential diagnosis, and to present the problems arising, especially in bilateral same canal involvement.
2. Patients and methods During the past 5 years (2006-2010), 345 patients examined at the neurotology unit of our department received diagnoses of BPPV. Thirty-two patients among them presented with BPPV of multiple canals and were included in the study. Their clinical records were retrospectively reviewed, and their age, sex, and the etiology and duration of their symptoms were recorded. Another 12 patients with possible multiple canal BPPV were excluded because of missing data and lack of follow-up or clinical examination,
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Anterior canal involvement was also characterized by paroxysmal positioning nystagmus with both a predominant linear component and a slight torsional component. Differential diagnosis between posterior and anterior canal disease was based on the direction of the vertical component of the fast phase of the nystagmus, being upward in cases of posterior canal involvement and downward in cases of anterior canal disease. The direction of the torsional component of the nystagmus is the key element to the identification of the involved side in patients with BPPV of the anterior canal. When the torsional component of the nystagmus was similar in direction with that of posterior canal BPPV, then involvement of the anterior canal of the same side at which the Dix-Hallpike maneuver was performed might be inferred. When the torsional component of the nystagmus had the opposite direction, disease of the contralateral anterior canal was implied [5]. Finally, the horizontal canal type of vertigo was diagnosed by the presence of horizontal geotropic or apogeotropic paroxysmal nystagmus provoked by the supine roll test, performed by turning the head from the supine to either lateral position. The geotropic type of horizontal nystagmus denoted canalolithiasis of the lateral canal on the side with the more intense nystagmus, whereas the apogeotropic variety was indicative of cupulolithiasis (or canalolithiasis of the short arm of the lateral canal) on the side with the less intense nystagmus [10]. In Table 1, the diagnostic features of the positional nystagmus for each type
laboratory findings, and imaging studies suggesting pathologic conditions of the central nervous system. All patients underwent a complete otolaryngologic, audiological, and neurotologic evaluation, including puretone audiometry, measurements of acoustic immitance, and occasionally, auditory brainstem response. Eye movements were recorded by electronystagmography or videonystagmography using a standard test protocol of visual and vestibular stimulation described elsewhere [8]. Posterior or anterior canal BPPV were diagnosed with the help of the Dix-Hallpike maneuver. Intense vertigo accompanied by a burst of nystagmus with the typical characteristics of latency, crescendo, and transience was considered necessary to establish the diagnosis. A diagnosis of posterior canal involvement was based on the type of the paroxysmal positioning nystagmus produced during the Dix-Hallpike maneuver. The direction of the vertical component of the fast phase of the nystagmus response should be upward, and the torsional component of the nystagmus should be beating toward the “downside” affected ear: movement of the upper pole of the eye counterclockwise during the right DixHallpike maneuver when the right ear was involved and clockwise during the left Dix-Hallpike maneuver when the left ear was involved. Dix-Hallpike maneuver positive toward 1 side only, with the previously described features of nystagmus, denoted involvement of the posterior canal of the same side, whereas presence of a bilaterally positive maneuver implied bilateral posterior canal involvement [9].
Table 1 Diagnosis of the involved semicircular canal and the side of involvement, according to the appropriate diagnostic maneuver Vertical SC canals Involved SC canal
Diagnostic maneuver
P-BPPV R
Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike
P-BPPV L A-BPPV R A-BPPV L
Paroxysmal positioning nystagmus
R (+) L (−) R (−) L (+) R (+) L (+) R (+) L (+)
Vertical
Torsional
Upbeating No nystagmus No nystagmus Upbeating Downbeating Downbeating Downbeating Downbeating
Counterclockwise
Clockwise Counterclockwise Counterclockwise Clockwise Clockwise
Horizontal SC canals
H-BPPV
H-BPPV
Direction of nystagmus
Intensity of nystagmus
Pathogenetic mechanism
Supine roll test ipsilateral (+) Supine roll test contralateral (+) Supine roll test ipsilateral (+)
Geotropic
More intense
Canalolithiasis
Geotropic
Less intense
Apogeotropic
Less intense
Supine roll test L contralateral (+)
Apogeotropic
More intense
SC indicates semicircular; R, right; L, left; P, posterior; A, anterior; H, horizontal.
Cupulolithiasis or canalolithiasis of the short arm of the horizontal SC
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of BPPV, according to the canal involved, are shown. Diagnosis of multiple canal BPPV is based on combination of these findings. Posterior canal BPPV was treated by the modified Epley canalith repositioning procedure (CRP) [11]. Anterior canal BPPV was treated by the reverse Epley or a maneuver specifically invented for this canal [12]. Briefly, this maneuver, which is an Epley variation, begins with the head-hanging position and maximal neck extension with torsion of the head 45° to the affected side, obtaining thus slight movement of otoconia toward the top of the canal. Next, by turning the patient's head 90° toward the healthy side in head-hanging position, otoconia are expected to move further toward the utricle. The CRP ends with quick return to the sitting position, expecting movement of otoconia into the utricle because of the synergic action of gravity and angular acceleration. All 3 steps of the maneuver are maintained for 1 minute. Finally, horizontal canal BPPV was treated by the barbecue or the Gufoni maneuver, in case of geotropic or apogeotropic nystagmus, respectively [13]. Repeat sessions each 2 days were held, treating 1 only canal during each session, or repeating previous therapeutic CRPs if incomplete remission of the symptoms was noticed. The order of application of the appropriate CRP, according to the involved canal, was horizontal, posterior, and anterior canal. The horizontal canal BPPV was treated first because it is known to present with more intense symptoms [3]. Assessment of the success of the treatment included both the patient's report of relief from vertigo and a negative DixHallpike test or supine roll test result, for at least 2 months. Follow-up care included visits every 6 months or earlier in case the symptoms recurred. In such cases, the repositioning procedures were repeated according to the same plan. After 2 years of absence of symptoms, it was considered that definite cure had been achieved. Follow-up data were available for most patients for more than 2 years.
3. Results Thirty-two patients (9.3%) from the total of 345 were found with multiple canal involvement. Thirteen patients were men and 19 were women, with a mean age 60.4 (±9.6)
and 56.8 (±12.7) years, respectively. All patients presented after a long duration of symptoms, exceeding in most cases 3 months (average time from onset of symptoms to treatment, 6.5 months). The results of neurologic examination were normal in all patients, but because of concern about a central cause, all of them underwent magnetic resonance imaging of the brain, the results of which were normal. From the history of our patients, posttraumatic BPPV in 11 patients, viral infections in 4 patients, and chronic otitis media in another 2 patients were referred. In most of the patients, vertigo was related to sleeping, and vertiginous episodes were provoked either when the patient first lay back, rolled to one side or the other, or arose from bed. In addition, several head movements during the day, such as hyperextension or rapid flexion of the head, triggered a vertiginous episode. When the horizontal canal was involved, the patient complained for intense vertigo, when turning the head to either side in the supine position, usually being more pronounced in the pathologic side. In Table 2, the results regarding occurrence of semicircular canal involvement and treatment are shown. Mean follow-up time was 25 months (median, 24; range, 12-36 months). A total of 21 patients showed bilateral posterior canal involvement. The remaining 11 patients had involvement of different canals, either on the same side (7 cases) or on different sides (4 cases). From the first subgroup, 5 patients had ipsilateral disease of the posterior and horizontal canal on the same side, whereas another 2 had ipsilateral involvement of the anterior and horizontal canal. From the second subgroup, 2 patients had horizontal and anterior canal disease, and another 2 had horizontal and posterior canal involvement. All patients with horizontal canal involvement had nystagmus of the geotropic type (canalolithiasis) apart from 1, who had nystagmus of the apogeotropic type (cupulolithiasis), in conjunction with involvement of the contralateral posterior canal. Almost all patients were cured (97%) after repeated therapeutic sessions, with an average of 2.9 therapeutic sessions per patient (Table 2). In 16 patients (50%), only 2 therapeutic sessions were needed, 1 for each diseased canal. In 1 patient with posterior canal and contralateral horizontal canal BPPV of the apogeotropic type, a maximum of 7 sessions was reached, mainly for treatment of the horizontal
Table 2 Occurrence of semicircular canal involvement and treatment data Patients (N)
Involved SCC
21 4 1 2 2 1 1
R posterior SCC R posterior SCC L posterior SCC R anterior SCC R horizontal SCC L posterior SCC R posterior SCC
SCC indicates semicircular canal.
L posterior SCC R horizontal SCC L horizontal SCC R horizontal SCC L anterior SCC R horizontal SCC (apogeotropic) L horizontal SCC
No. of therapeutic sessions
Failure
Recurrence
2.7 3.2 3 2.5 3 7 3
– 1 – – – – –
4 (1 posterior SCC) – – 1 (R horizontal SCC) – – –
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type of apogeotropic nystagmus, which has been reported as being quite difficult to treat [14]. In 1 patient only (3%), treatment partially failed because the horizontal BPPV responded to treatment but the posterior canal did not. However, recurrences were observed in 5 patients (15.6%), concerning this time, one only semicircular canal, but all of them were successfully treated by repeating the appropriate CRP.
4. Discussion Multiple-canal BPPV included either involvement of the same canal on both sides or simultaneous involvement of different canals on the same or on both sides. Most of our patients belonged to the first category (21 patients, or 6%), which included only patients with bilateral posterior canal BPPV. Fewer patients (11, or 3.2%) belonged to the second category. These data originate from a tertiary referral center, and it is possible that this proportion of multiple canal involvement may be artificially elevated, considering the probability of treatment of numerous patients with typical BPPV by primary or secondary care physicians, whereas more complex cases are referred in tertiary centers. All patients with bilateral same canal involvement had disease of the posterior canal. This clinical entity is not quite rare, accounting for 6% to 26% in the reported BPPV series [15]. Diagnosis of bilateral posterior canal involvement is relatively easy after a bilateral positive Dix-Hallpike with typical mixed nystagmus, but care should be taken to avoid the erroneous diagnosis of pseudobilateral posterior canal BPPV as true bilateral BPPV. The entity of unilateral mimicking bilateral BPPV was first described by Steddin and Brandt [16]. According to these authors, inappropriate head positioning during testing of the unaffected ear causes displacement of the affected canal from its perpendicular position. This makes the otolith debris move gravitationally toward the cupula, causing thus transient cupulolithiasis and evoking an inhibitory nystagmus. This nystagmus is directed toward the unaffected ear, and this situation may be erroneously diagnosed as bilateral posterior canal BPPV. The inhibitory nystagmus usually has a lower amplitude and frequency than the excitatory nystagmus of the affected ear, and patients report milder symptoms when the unaffected ear is tested. Although it is often difficult to distinguish between true bilateral and pseudobilateral posterior canal BPPV, there are some clinical observations, which may be useful [15,17]. First, the presence of asymmetric nystagmus and symptoms of different intensity during right and left Dix-Hallpike maneuvers should arouse the suspicion of pseudobilateral posterior BPPV. Accordingly, the side with more intense nystagmus and symptoms should be treated first. Disappearance of symptoms and signs is evidence of previous pseudobilateral posterior BPPV. Second, a head-down test, performed as extension of the head directly backward from
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the sitting to the supine straight-head hanging position, might be helpful. During this test, both posterior canals get irritated, resulting in the appearance of nystagmus. However, this nystagmus has only a vertical upbeating component, whereas the torsional components having opposite directions are cancelled. True bilateral BPPV may be concluded in this case, whereas in case that the nystagmus retains its torsional component, pseudobilateral BPPV is probable. The true side of the disease may be found, observing the direction of this component, which beats clockwise on left posterior canal BPPV and counterclockwise on right posterior canal involvement. Finally, the criterion of responsiveness to treatment is quite valid. Successful treatment of the patient after performing the appropriate CRP on the side with more intense manifestations is proof of previous pseudobilateral BPPV. In all our patients, treatment of 1 side was not sufficient, and repeat of the Epley maneuver on at least one more session on the contralateral side was necessary to obtain a negative DixHallpike test and remission of the symptoms. In the presented cases, I may have missed some patients with bilateral anterior or bilateral horizontal canal BPPV. However, I believe that it is extremely difficult to diagnose such cases. It is generally accepted that anterior canal BPPV produces bilaterally positive Dix-Hallpike maneuvers [18]. During a contralateral Dix-Hallpike maneuver, the head rotates in the plane of the affected anterior canal (Fig. 1), whereas during an ipsilesional Dix-Hallpike maneuver, the head rotates orthogonally to the plane of the involved anterior canal (Fig. 2). On both instances, the maneuver will be positive because of the almost vertical orientation of the ampullary segment of the anterior canal. During the contralateral Dix-Hallpike test, the affected anterior canal is stimulated because of the movement of endolymph that takes place in its rotation plane. During the ipsilesional DixHallpike test, the ampullary segment of the canal will also point downward at approximately 40° off vertical. Consequently, displacement of otoconia in the involved anterior canal is induced, and the test will be positive, although the provoked pressure against the cupula and the corresponding symptoms are expected to be less pronounced. In addition, the torsional nystagmic component is smaller for the anterior than the posterior canal because the anterior canals are placed nearer to the sagittal plane, in comparison with the posterior canals. Accordingly, there is an upward bias in the vertical slow-phase eye velocity, and more downbeat than torsional nystagmus is expected from anterior canal BPPV, as well as more torsional than upbeat nystagmus in posterior canal BPPV. It has been observed in several instances that the torsional component may be completely absent in anterior canal BPPV and the disease may manifest as pure downbeating nystagmus, mimicking a central nervous system disease [12]. The case of bilateral anterior canal poses quite interesting diagnostic issues. Theoretically, the Dix-Hallpike maneuver on 1 side would cause paroxysmal nystagmus with a vertical
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Fig. 1. Stimulation of the left anterior semicircular canal (left panel) during the right Dix-Hallpike maneuver (right panel). When otoconia are present, the affected anterior canal is stimulated because of the movement of endolymph that takes place in its rotation plane, inducing BPPV.
downbeating component and a torsional component with the upper pole of the eye beating apogeotropically. This type of nystagmus is attributed to stimulation of the contralateral anterior canal [5,18]. However, as previously discussed, the ipsilateral anterior canal would be also excited, resulting in a downbeating vertical component and a torsional component in the opposite direction, but probably of smaller intensity. Vectorial summation of all the components would result in an intense vertical downbeating component and a weak torsional apogeotropic component because of addition of the vertical and subtraction of the torsional components. To summarize, the Dix-Hallpike maneuvers on both sides would produce a mixed nystagmus, with an intense vertical and a
weak or absent torsional component, both opposite to those of posterior canal involvement. Differential diagnosis would be difficult because in unilateral anterior BPPV, the torsional nystagmic vector may be quite often absent. Furthermore, in a head-down test, performed as in the case of bilateral posterior canal BPPV, both anterior canals would get irritated, resulting in the appearance of nystagmus. This nystagmus would manifest as intense purely vertical and downbeating because the torsional components would cancel each other as having opposite directions. Differential diagnosis on these grounds would not be safe because unilateral anterior canal involvement, as previously mentioned, may be present with purely vertical nystagmus as well.
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Fig. 2. Stimulation of the right anterior semicircular canal (middle panel) during the right Dix-Hallpike maneuver (right panel). When otoconia are present, the head rotates orthogonally to the plane of the affected anterior canal. However, because of the almost vertical orientation of its ampullary segment, displacement of otoconia is induced as well and the test will be positive.
Finally, the criterion of responsiveness to treatment is not clear in this case. There is no established therapeutic maneuver for the treatment of anterior canal BPPV, and for this disease, it has been reported that both the Epley and the reverse Epley maneuver, as well as several other specific maneuvers, may be useful [19]. To conclude, although I did not find any case with clear manifestations of bilateral anterior BPPV, this entity has been previously reported [20]. However, any details concerning its diagnosis and treatment are missing and I believe that its diagnosis is currently highly speculative.
Bilateral horizontal canal BPPV is also quite difficult to diagnose. The critical point in this case is that unilateral horizontal canal BPPV produces during the supine roll test horizontal nystagmus on both sides, either geotropic (canalolithiasis) or apogeotropic (cupulolithiasis). In a theoretical case of bilateral horizontal BPPV with geotropic nystagmus, supine roll on either side would result in excitation of the horizontal canal of the lowermost ear because of ampullopetal endolymph flow and at the same time inhibition of the horizontal canal of the uppermost ear
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because of ampullofugal endolymph flow (Fig. 3). Vectorial summation would result in an intense, more or less symmetric geotropic nystagmus. In the hypothetical case of bilateral horizontal BPPV with apogeotropic nystagmus owed to cupulolithiasis, supine roll test on either side would result in inhibition of the horizontal canal of the lowermost ear because of ampullofugal movement of the cupula and at the same time excitation of the horizontal canal of the uppermost ear because of ampullopetal cupular movement (Fig. 4). Vectorial summation would result in an intense symmetric apogeotropic nystagmus. In both cases, the nystagmus would be more intense than in unilateral horizontal canal involvement because of the additional excitation of the uppermost horizontal canal. To summarize, bilateral horizontal canal BPPV would manifest as bilateral, intense, probably symmetric either geotropic or apogeotropic nystagmus owed to canalolithiasis or cupulolithiasis, respectively. I have found several patients with symmetric geotropic horizontal nystagmus, but in all cases, the side of involvement could be detected by other means, such as the
Fig. 4. Mechanism of cupulolithiasis of bilateral apogeotropic horizontal canal BPPV. Up, Patient in supine position with debris adherent to the cupulae bilaterally. Down, Supine roll test on either side would result in inhibition of the horizontal canal of the lowermost ear, triggering an apogeotropic horizontal nystagmus, and at the same time, excitation of the horizontal canal of the uppermost ear. Vectorial summation would result in intense, more or less symmetric, apogeotropic nystagmus.
Fig. 3. Mechanism of canalolithiasis of bilateral geotropic horizontal canal BPPV. Up, Patient in supine position with debris in the posterior part of both horizontal canals. Down, Supine roll test on either side would result in excitation of the horizontal canal of the lowermost ear and, concurrently, inhibition of the horizontal canal of the uppermost ear. Vectorial summation would result in intense, symmetric geotropic nystagmus.
presence of horizontal pseudonystagmus or the head-down test [21-22]. In addition, performance of the barbecue maneuver on the suspected affected side resulted in remission of the symptoms. It should be finally noticed that the criterion of symmetry of the nystagmus to diagnose bilateral horizontal canal BPPV is not a solid one because asymmetric involvement of the 2 horizontal canals may occur as well, making its diagnosis almost impossible. Involvement of different canals, either on the same side or on both sides, is easier to diagnose. I found 11 such cases (3.2%), including 7 cases with involvement of the posterior and the horizontal canal, either unilaterally (5 cases) or bilaterally (2 cases) and 4 cases of concomitant involvement of the horizontal and the anterior canal (2 bilaterally and 2 unilaterally). I did not find any patients with simultaneous involvement of the posterior and the anterior canal, although this combination has been previously reported [7,20]. Synchronous involvement of the posterior and horizontal canal is a quite common type of mixed vertigo, as has been
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reported in several series, in percentages ranging from 4.4% [23] to 21.2% [24]. Leopardi et al [23], in a multicenter study of 794 patients with BPPV, found 4.4% cases with multiple canal involvement. The authors observed a clear predominance of unilateral forms (posterior and horizontal canals on the same side) but also found several cases of bilateral forms of posttraumatic origin. Moon et al [25], in a multicenter study of BPPV in Korea, found similar results, with multiple canal involvement approaching 5%, with the combination of posterior and horizontal canal being the most common (79.8%). Macias et al [26] found 6.9% of their patients with bilateral involvement (probably of the posterior canal) and 5% with multiple canal involvement, probably of the posterior and horizontal canal variety, because the authors could not at the time of the publication recognize any anterior canal BPPV. In several other reports, larger percentages of multiple canal involvement were found, such as 21.3% in a study of 986 patients with BPPV by Nakayama and Epley [24], who did not provide any specific details about which canals were involved. Lopez-Escamez et al [20], in a study of 80 patients with BPPV, found 14 patients with downbeating positional nystagmus (17.5%), but a detailed study of these cases showed 12 cases of anterior canal BPPV (9 unilateral and 3 bilateral), 1 with horizontal-anterior canal and 1 with posterior-anterior canal BPPV. Finally, Tomaz et al [7], in a retrospective study of 2345 patients, found 35 cases with multiple canal involvement (1.5%) and 252 cases with bilateral involvement (10.7%), either of the posterior (9.9%) or of the anterior canal (0.8%). It should be noticed, however, that we should be skeptical of the diagnosis of bilateral anterior BPPV, and the authors of the 2 previous studies do not provide any detailed criteria on this issue. Treatment was successful in most patients, and these results agree with most other series [23-26]. Provided that accurate diagnosis has been obtained, treatment with successive CRPs, according to the canals involved, has excellent results, comparable with those of single-canal BPPV treatment [27]. In most cases, 2 to 4 therapeutic sessions were adequate, treating a single involved canal on each session and never both of them. However, in 1 case with mixed posterior and horizontal canal of the apogeotropic type BPPV, 7 sessions were needed because of the difficulty of treating cupulolithiasis of the horizontal canal, which usually needs repeated performance of the maneuvers. Cupulolithiasis of the horizontal canal in multiple-canal involvement is quite rare and has been reported only once (canalolithiasis of the posterior canal and cupulolithiasis of the ipsilateral horizontal canal) [28]. Finally, it should be noticed that traumatic origin is quite common in mixed canal BPPV, as previously reported [1,7,29]. In this material, head and neck trauma accounted for mixed BPPV in 11 patients (34.3%), as compared with the percentage of 7% in a singlecanal BPPV group. The issue of differential diagnosis of BPPV from various central vestibular disorders should be also briefly discussed.
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The most significant central causes include central positional vertigo, transient vertebrobasilar ischemia, and migrainous positional vertigo. Several central positional vertigo syndromes have been described, characterized mainly by prolonged nystagmus, usually downbeating, vertigo, and vomiting [30]. All central forms of positional vertigo involve the region around the vestibular nuclei and a neural loop to the cerebellar vermis. Probably, the most helpful features in differential diagnosis from peripheral BPPV is atypical nystagmus, prolonged vertigo, frequent vomiting, and usually absence of latency, fatiguability, and habituation on repetitive stimulation. In addition, brain imaging studies may reveal lesions dorsolateral to the fourth ventricle and of the dorsal vermis, such as tumors, hemorrhages, infarctions, or multiple sclerosis. Transient vertebrobasilar ischemia may be attributed to a functional compression of the vertebral artery, especially in elderly patients with atheromas, cervical spondylosis, or osteophyta that narrow the transverse foramina. During rotational head motion, transient ischemic vertiginous attacks may be induced, which terminate when the head is returned to a normal upright position. Differential diagnosis may be obtained from the clinical manifestations, which besides the vertigo and, occasionally, accompanying nystagmus, may include diplopia, field defects, visual illusions, dysphagia, dysarthria, drop attacks, or motor symptoms. Finally, migrainous vertigo mimicking BPPV (especially of the horizontal canal) may also occur [31]. Useful features in differential diagnosis of migrainous positional vertigo include short-duration symptomatic episodes and frequent recurrences of at least moderate intensity, manifestation early in life, migrainous symptoms during episodes with positional vertigo, atypical positional nystagmus, and failure of treatment by CRPs. In conclusion, in multiple canal BPPV, several difficult diagnostic and treatment issues arise. However, accurate diagnosis based on the nystagmus features of the involved canals leads to the appropriate choice of CRPs, resulting thus to successful treatment of the disorder. References [1] Katsarkas A. Benign paroxysmal positional vertigo (BPPV): idiopathic versus post-traumatic. Acta Otolaryngol 1999;119:745-9. [2] Korres SG, Balatsouras DG. Diagnostic, pathophysiologic, and therapeutic aspects of benign paroxysmal positional vertigo. Otolaryngol Head Neck Surg 2004;131:438-44. [3] Parnes LS, Agrawal SK, Atlas J. Diagnosis and management of benign paroxysmal positional vertigo (BPPV). CMAJ 2003;169:681-93. [4] Uno A, Moriwaki K, Kato T, et al. Clinical features of benign paroxysmal positional vertigo. Nippon Jibiinkoka Gakkai Kaiho 2001; 104:9-16. [5] Korres S, Riga M, Balatsouras D, et al. Benign paroxysmal positional vertigo of the anterior semicircular canal: atypical clinical findings and possible underlying mechanisms. Int J Audiol 2008;47:276-82. [6] Lopez-Escamez JA, Molina MI, Gamiz M, et al. Multiple positional nystagmus suggests multiple canal involvement in benign paroxysmal vertigo. Acta Otolaryngol 2005;125:954-61.
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[20] Lopez-Escamez JA, Molina MI, Gamiz MJ. Anterior semicircular canal benign paroxysmal positional vertigo and positional downbeating nystagmus. Am J Otolaryngol 2006;27:173-8. [21] Nuti D, Mandalà M, Salerni L. Lateral canal paroxysmal positional vertigo revisited. Ann N Y Acad Sci 2009;1164:316-23. [22] Choung YH, Shin YR, Kahng H, et al. ‘Bow and lean test’ to determine the affected ear of horizontal canal benign paroxysmal positional vertigo. Laryngoscope 2006;116:1776-81. [23] Leopardi G, Chiarella G, Serafini G, et al. Paroxysmal positional vertigo: short- and long-term clinical and methodological analyses of 794 patients. Acta Otorhinolaryngol Ital 2003;23:155-60. [24] Nakayama M, Epley JM. BPPV and variants: improved treatment results with automated, nystagmus-based repositioning. Otolaryngol Head Neck Surg 2005;133:107-12. [25] Moon SY, Kim JS, Kim BK, et al. Clinical characteristics of benign paroxysmal positional vertigo in Korea: a multicenter study. J Korean Med Sci 2006;21:539-43. [26] Macias JD, Lambert KM, Massingale S, et al. Variables affecting treatment in benign paroxysmal positional vertigo. Laryngoscope 2000;110:1921-4. [27] Korres S, Balatsouras DG, Kaberos A, et al. Occurrence of semicircular canal involvement in benign paroxysmal positional vertigo. Otol Neurotol 2002;23:926-32. [28] Imai T, Takeda N, Ito M, et al. Benign paroxysmal positional vertigo due to a simultaneous involvement of both horizontal and posterior semicircular canals. Audiol Neurootol 2006;11:198-205. [29] Korres S, Balatsouras DG, Ferekidis E. Prognosis of patients with benign paroxysmal positional vertigo treated with repositioning maneuvers. J Laryngol Otol 2006;120:528-33. [30] Brandt T. Central positional vertigo. In: & Brandt T, editor. Vertigo: its multisensory syndromes. London: Springer; 2003. p. 291-9. [31] Roberts RA, Gans RE, Kastner AH. Differentiation of migrainous positional vertigo (MPV) from horizontal canal bening paroxysmal positional vertigo (HC-BPPV). Int J Audiol 2006;45:224-6.
American Journal of Otolaryngology–Head and Neck Medicine and Surgery 33 (2012) 250 – 258 www.elsevier.com/locate/amjoto
Benign paroxysmal positional vertigo with multiple canal involvement Dimitrios G. Balatsouras, MD, PhD⁎ ENT Department, Tzanion General Hospital of Pireaus, Pireaus, Greece Received 16 March 2011
Abstract
Purpose: The aims of this study were to describe the frequency and clinical features of benign paroxysmal positional vertigo (BPPV) with multiple canal involvement and to evaluate the results of treatment by appropriate canalith repositioning procedures. Materials and Methods: A total of 345 patients were referred for BPPV between 2006 and 2010. Thirty-two of them (9.3%) who had BPPV of multiple canals were studied. Thirteen were men (mean age, 60.4 years) and 19 were women (mean age, 56.8 years). Dix-Hallpike and supine roll tests were performed for diagnosis. Canalith repositioning procedures for treatment included modified Epley, barbecue, Gufoni, and anterior BPPV-specific maneuvers. Results: Twenty-one patients had bilateral posterior canal BPPV, and 11 had mixed canal BPPV either on the same side (7 patients) or on both sides (4 patients). Thirty-one patients were cured with an average of 2.9 therapeutic sessions per patient. Recurrences occurred in 5 patients (15.6%). Conclusions: Benign paroxysmal positional vertigo of multiple canals is not rare and presents a clinical challenge. However, accurate diagnosis results in successful treatment comparable with BPPV of 1 canal. © 2012 Elsevier Inc. All rights reserved.
1. Introduction Benign paroxysmal positional vertigo (BPPV) is one of the most common clinical entities encountered in a neurotology clinic [1]. This disorder is associated with a characteristic paroxysmal positional nystagmus, which may be torsional, vertical, or horizontal, and is characterized by findings such as latency, crescendo and decrescendo, transience, reversibility, and fatiguability [2]. Although in most cases of BPPV the posterior canal is involved, BPPV of the horizontal canal occurs in a smaller rate, ranging from 5% to 30% according to various reports [3-4], and more rarely, involvement of the anterior canal may be observed [5]. Disease of multiple canals, either bilaterally or on the same side, represents a small fraction only of the patients with BPPV, but their presentation is quite interesting because of the various diagnostic and therapeutic challenges arising.
⁎ 23 Achaion Str. – Agia Paraskevi, Athens – 15343, Greece. Tel.: +30 210 6004683; +30 6945547980(Mobile); fax: +30 210 4592671. E-mail address: [email protected]. 0196-0709/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.amjoto.2011.07.007
In several studies [6-7], such cases have been occasionally reported, but the various pathogenetic and diagnostic issues need further discussion. The aim of this study is to present a series of patients with BPPV with multiple canal involvement diagnosed and treated in the Neurotology Unit of an Otolaryngology department during the last 5 years. I intended also to present an in-depth discussion of the nystagmus characteristics, which should be useful in differential diagnosis, and to present the problems arising, especially in bilateral same canal involvement.
2. Patients and methods During the past 5 years (2006-2010), 345 patients examined at the neurotology unit of our department received diagnoses of BPPV. Thirty-two patients among them presented with BPPV of multiple canals and were included in the study. Their clinical records were retrospectively reviewed, and their age, sex, and the etiology and duration of their symptoms were recorded. Another 12 patients with possible multiple canal BPPV were excluded because of missing data and lack of follow-up or clinical examination,
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Anterior canal involvement was also characterized by paroxysmal positioning nystagmus with both a predominant linear component and a slight torsional component. Differential diagnosis between posterior and anterior canal disease was based on the direction of the vertical component of the fast phase of the nystagmus, being upward in cases of posterior canal involvement and downward in cases of anterior canal disease. The direction of the torsional component of the nystagmus is the key element to the identification of the involved side in patients with BPPV of the anterior canal. When the torsional component of the nystagmus was similar in direction with that of posterior canal BPPV, then involvement of the anterior canal of the same side at which the Dix-Hallpike maneuver was performed might be inferred. When the torsional component of the nystagmus had the opposite direction, disease of the contralateral anterior canal was implied [5]. Finally, the horizontal canal type of vertigo was diagnosed by the presence of horizontal geotropic or apogeotropic paroxysmal nystagmus provoked by the supine roll test, performed by turning the head from the supine to either lateral position. The geotropic type of horizontal nystagmus denoted canalolithiasis of the lateral canal on the side with the more intense nystagmus, whereas the apogeotropic variety was indicative of cupulolithiasis (or canalolithiasis of the short arm of the lateral canal) on the side with the less intense nystagmus [10]. In Table 1, the diagnostic features of the positional nystagmus for each type
laboratory findings, and imaging studies suggesting pathologic conditions of the central nervous system. All patients underwent a complete otolaryngologic, audiological, and neurotologic evaluation, including puretone audiometry, measurements of acoustic immitance, and occasionally, auditory brainstem response. Eye movements were recorded by electronystagmography or videonystagmography using a standard test protocol of visual and vestibular stimulation described elsewhere [8]. Posterior or anterior canal BPPV were diagnosed with the help of the Dix-Hallpike maneuver. Intense vertigo accompanied by a burst of nystagmus with the typical characteristics of latency, crescendo, and transience was considered necessary to establish the diagnosis. A diagnosis of posterior canal involvement was based on the type of the paroxysmal positioning nystagmus produced during the Dix-Hallpike maneuver. The direction of the vertical component of the fast phase of the nystagmus response should be upward, and the torsional component of the nystagmus should be beating toward the “downside” affected ear: movement of the upper pole of the eye counterclockwise during the right DixHallpike maneuver when the right ear was involved and clockwise during the left Dix-Hallpike maneuver when the left ear was involved. Dix-Hallpike maneuver positive toward 1 side only, with the previously described features of nystagmus, denoted involvement of the posterior canal of the same side, whereas presence of a bilaterally positive maneuver implied bilateral posterior canal involvement [9].
Table 1 Diagnosis of the involved semicircular canal and the side of involvement, according to the appropriate diagnostic maneuver Vertical SC canals Involved SC canal
Diagnostic maneuver
P-BPPV R
Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike Dix-Hallpike
P-BPPV L A-BPPV R A-BPPV L
Paroxysmal positioning nystagmus
R (+) L (−) R (−) L (+) R (+) L (+) R (+) L (+)
Vertical
Torsional
Upbeating No nystagmus No nystagmus Upbeating Downbeating Downbeating Downbeating Downbeating
Counterclockwise
Clockwise Counterclockwise Counterclockwise Clockwise Clockwise
Horizontal SC canals
H-BPPV
H-BPPV
Direction of nystagmus
Intensity of nystagmus
Pathogenetic mechanism
Supine roll test ipsilateral (+) Supine roll test contralateral (+) Supine roll test ipsilateral (+)
Geotropic
More intense
Canalolithiasis
Geotropic
Less intense
Apogeotropic
Less intense
Supine roll test L contralateral (+)
Apogeotropic
More intense
SC indicates semicircular; R, right; L, left; P, posterior; A, anterior; H, horizontal.
Cupulolithiasis or canalolithiasis of the short arm of the horizontal SC
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of BPPV, according to the canal involved, are shown. Diagnosis of multiple canal BPPV is based on combination of these findings. Posterior canal BPPV was treated by the modified Epley canalith repositioning procedure (CRP) [11]. Anterior canal BPPV was treated by the reverse Epley or a maneuver specifically invented for this canal [12]. Briefly, this maneuver, which is an Epley variation, begins with the head-hanging position and maximal neck extension with torsion of the head 45° to the affected side, obtaining thus slight movement of otoconia toward the top of the canal. Next, by turning the patient's head 90° toward the healthy side in head-hanging position, otoconia are expected to move further toward the utricle. The CRP ends with quick return to the sitting position, expecting movement of otoconia into the utricle because of the synergic action of gravity and angular acceleration. All 3 steps of the maneuver are maintained for 1 minute. Finally, horizontal canal BPPV was treated by the barbecue or the Gufoni maneuver, in case of geotropic or apogeotropic nystagmus, respectively [13]. Repeat sessions each 2 days were held, treating 1 only canal during each session, or repeating previous therapeutic CRPs if incomplete remission of the symptoms was noticed. The order of application of the appropriate CRP, according to the involved canal, was horizontal, posterior, and anterior canal. The horizontal canal BPPV was treated first because it is known to present with more intense symptoms [3]. Assessment of the success of the treatment included both the patient's report of relief from vertigo and a negative DixHallpike test or supine roll test result, for at least 2 months. Follow-up care included visits every 6 months or earlier in case the symptoms recurred. In such cases, the repositioning procedures were repeated according to the same plan. After 2 years of absence of symptoms, it was considered that definite cure had been achieved. Follow-up data were available for most patients for more than 2 years.
3. Results Thirty-two patients (9.3%) from the total of 345 were found with multiple canal involvement. Thirteen patients were men and 19 were women, with a mean age 60.4 (±9.6)
and 56.8 (±12.7) years, respectively. All patients presented after a long duration of symptoms, exceeding in most cases 3 months (average time from onset of symptoms to treatment, 6.5 months). The results of neurologic examination were normal in all patients, but because of concern about a central cause, all of them underwent magnetic resonance imaging of the brain, the results of which were normal. From the history of our patients, posttraumatic BPPV in 11 patients, viral infections in 4 patients, and chronic otitis media in another 2 patients were referred. In most of the patients, vertigo was related to sleeping, and vertiginous episodes were provoked either when the patient first lay back, rolled to one side or the other, or arose from bed. In addition, several head movements during the day, such as hyperextension or rapid flexion of the head, triggered a vertiginous episode. When the horizontal canal was involved, the patient complained for intense vertigo, when turning the head to either side in the supine position, usually being more pronounced in the pathologic side. In Table 2, the results regarding occurrence of semicircular canal involvement and treatment are shown. Mean follow-up time was 25 months (median, 24; range, 12-36 months). A total of 21 patients showed bilateral posterior canal involvement. The remaining 11 patients had involvement of different canals, either on the same side (7 cases) or on different sides (4 cases). From the first subgroup, 5 patients had ipsilateral disease of the posterior and horizontal canal on the same side, whereas another 2 had ipsilateral involvement of the anterior and horizontal canal. From the second subgroup, 2 patients had horizontal and anterior canal disease, and another 2 had horizontal and posterior canal involvement. All patients with horizontal canal involvement had nystagmus of the geotropic type (canalolithiasis) apart from 1, who had nystagmus of the apogeotropic type (cupulolithiasis), in conjunction with involvement of the contralateral posterior canal. Almost all patients were cured (97%) after repeated therapeutic sessions, with an average of 2.9 therapeutic sessions per patient (Table 2). In 16 patients (50%), only 2 therapeutic sessions were needed, 1 for each diseased canal. In 1 patient with posterior canal and contralateral horizontal canal BPPV of the apogeotropic type, a maximum of 7 sessions was reached, mainly for treatment of the horizontal
Table 2 Occurrence of semicircular canal involvement and treatment data Patients (N)
Involved SCC
21 4 1 2 2 1 1
R posterior SCC R posterior SCC L posterior SCC R anterior SCC R horizontal SCC L posterior SCC R posterior SCC
SCC indicates semicircular canal.
L posterior SCC R horizontal SCC L horizontal SCC R horizontal SCC L anterior SCC R horizontal SCC (apogeotropic) L horizontal SCC
No. of therapeutic sessions
Failure
Recurrence
2.7 3.2 3 2.5 3 7 3
– 1 – – – – –
4 (1 posterior SCC) – – 1 (R horizontal SCC) – – –
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type of apogeotropic nystagmus, which has been reported as being quite difficult to treat [14]. In 1 patient only (3%), treatment partially failed because the horizontal BPPV responded to treatment but the posterior canal did not. However, recurrences were observed in 5 patients (15.6%), concerning this time, one only semicircular canal, but all of them were successfully treated by repeating the appropriate CRP.
4. Discussion Multiple-canal BPPV included either involvement of the same canal on both sides or simultaneous involvement of different canals on the same or on both sides. Most of our patients belonged to the first category (21 patients, or 6%), which included only patients with bilateral posterior canal BPPV. Fewer patients (11, or 3.2%) belonged to the second category. These data originate from a tertiary referral center, and it is possible that this proportion of multiple canal involvement may be artificially elevated, considering the probability of treatment of numerous patients with typical BPPV by primary or secondary care physicians, whereas more complex cases are referred in tertiary centers. All patients with bilateral same canal involvement had disease of the posterior canal. This clinical entity is not quite rare, accounting for 6% to 26% in the reported BPPV series [15]. Diagnosis of bilateral posterior canal involvement is relatively easy after a bilateral positive Dix-Hallpike with typical mixed nystagmus, but care should be taken to avoid the erroneous diagnosis of pseudobilateral posterior canal BPPV as true bilateral BPPV. The entity of unilateral mimicking bilateral BPPV was first described by Steddin and Brandt [16]. According to these authors, inappropriate head positioning during testing of the unaffected ear causes displacement of the affected canal from its perpendicular position. This makes the otolith debris move gravitationally toward the cupula, causing thus transient cupulolithiasis and evoking an inhibitory nystagmus. This nystagmus is directed toward the unaffected ear, and this situation may be erroneously diagnosed as bilateral posterior canal BPPV. The inhibitory nystagmus usually has a lower amplitude and frequency than the excitatory nystagmus of the affected ear, and patients report milder symptoms when the unaffected ear is tested. Although it is often difficult to distinguish between true bilateral and pseudobilateral posterior canal BPPV, there are some clinical observations, which may be useful [15,17]. First, the presence of asymmetric nystagmus and symptoms of different intensity during right and left Dix-Hallpike maneuvers should arouse the suspicion of pseudobilateral posterior BPPV. Accordingly, the side with more intense nystagmus and symptoms should be treated first. Disappearance of symptoms and signs is evidence of previous pseudobilateral posterior BPPV. Second, a head-down test, performed as extension of the head directly backward from
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the sitting to the supine straight-head hanging position, might be helpful. During this test, both posterior canals get irritated, resulting in the appearance of nystagmus. However, this nystagmus has only a vertical upbeating component, whereas the torsional components having opposite directions are cancelled. True bilateral BPPV may be concluded in this case, whereas in case that the nystagmus retains its torsional component, pseudobilateral BPPV is probable. The true side of the disease may be found, observing the direction of this component, which beats clockwise on left posterior canal BPPV and counterclockwise on right posterior canal involvement. Finally, the criterion of responsiveness to treatment is quite valid. Successful treatment of the patient after performing the appropriate CRP on the side with more intense manifestations is proof of previous pseudobilateral BPPV. In all our patients, treatment of 1 side was not sufficient, and repeat of the Epley maneuver on at least one more session on the contralateral side was necessary to obtain a negative DixHallpike test and remission of the symptoms. In the presented cases, I may have missed some patients with bilateral anterior or bilateral horizontal canal BPPV. However, I believe that it is extremely difficult to diagnose such cases. It is generally accepted that anterior canal BPPV produces bilaterally positive Dix-Hallpike maneuvers [18]. During a contralateral Dix-Hallpike maneuver, the head rotates in the plane of the affected anterior canal (Fig. 1), whereas during an ipsilesional Dix-Hallpike maneuver, the head rotates orthogonally to the plane of the involved anterior canal (Fig. 2). On both instances, the maneuver will be positive because of the almost vertical orientation of the ampullary segment of the anterior canal. During the contralateral Dix-Hallpike test, the affected anterior canal is stimulated because of the movement of endolymph that takes place in its rotation plane. During the ipsilesional DixHallpike test, the ampullary segment of the canal will also point downward at approximately 40° off vertical. Consequently, displacement of otoconia in the involved anterior canal is induced, and the test will be positive, although the provoked pressure against the cupula and the corresponding symptoms are expected to be less pronounced. In addition, the torsional nystagmic component is smaller for the anterior than the posterior canal because the anterior canals are placed nearer to the sagittal plane, in comparison with the posterior canals. Accordingly, there is an upward bias in the vertical slow-phase eye velocity, and more downbeat than torsional nystagmus is expected from anterior canal BPPV, as well as more torsional than upbeat nystagmus in posterior canal BPPV. It has been observed in several instances that the torsional component may be completely absent in anterior canal BPPV and the disease may manifest as pure downbeating nystagmus, mimicking a central nervous system disease [12]. The case of bilateral anterior canal poses quite interesting diagnostic issues. Theoretically, the Dix-Hallpike maneuver on 1 side would cause paroxysmal nystagmus with a vertical
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Fig. 1. Stimulation of the left anterior semicircular canal (left panel) during the right Dix-Hallpike maneuver (right panel). When otoconia are present, the affected anterior canal is stimulated because of the movement of endolymph that takes place in its rotation plane, inducing BPPV.
downbeating component and a torsional component with the upper pole of the eye beating apogeotropically. This type of nystagmus is attributed to stimulation of the contralateral anterior canal [5,18]. However, as previously discussed, the ipsilateral anterior canal would be also excited, resulting in a downbeating vertical component and a torsional component in the opposite direction, but probably of smaller intensity. Vectorial summation of all the components would result in an intense vertical downbeating component and a weak torsional apogeotropic component because of addition of the vertical and subtraction of the torsional components. To summarize, the Dix-Hallpike maneuvers on both sides would produce a mixed nystagmus, with an intense vertical and a
weak or absent torsional component, both opposite to those of posterior canal involvement. Differential diagnosis would be difficult because in unilateral anterior BPPV, the torsional nystagmic vector may be quite often absent. Furthermore, in a head-down test, performed as in the case of bilateral posterior canal BPPV, both anterior canals would get irritated, resulting in the appearance of nystagmus. This nystagmus would manifest as intense purely vertical and downbeating because the torsional components would cancel each other as having opposite directions. Differential diagnosis on these grounds would not be safe because unilateral anterior canal involvement, as previously mentioned, may be present with purely vertical nystagmus as well.
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Fig. 2. Stimulation of the right anterior semicircular canal (middle panel) during the right Dix-Hallpike maneuver (right panel). When otoconia are present, the head rotates orthogonally to the plane of the affected anterior canal. However, because of the almost vertical orientation of its ampullary segment, displacement of otoconia is induced as well and the test will be positive.
Finally, the criterion of responsiveness to treatment is not clear in this case. There is no established therapeutic maneuver for the treatment of anterior canal BPPV, and for this disease, it has been reported that both the Epley and the reverse Epley maneuver, as well as several other specific maneuvers, may be useful [19]. To conclude, although I did not find any case with clear manifestations of bilateral anterior BPPV, this entity has been previously reported [20]. However, any details concerning its diagnosis and treatment are missing and I believe that its diagnosis is currently highly speculative.
Bilateral horizontal canal BPPV is also quite difficult to diagnose. The critical point in this case is that unilateral horizontal canal BPPV produces during the supine roll test horizontal nystagmus on both sides, either geotropic (canalolithiasis) or apogeotropic (cupulolithiasis). In a theoretical case of bilateral horizontal BPPV with geotropic nystagmus, supine roll on either side would result in excitation of the horizontal canal of the lowermost ear because of ampullopetal endolymph flow and at the same time inhibition of the horizontal canal of the uppermost ear
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because of ampullofugal endolymph flow (Fig. 3). Vectorial summation would result in an intense, more or less symmetric geotropic nystagmus. In the hypothetical case of bilateral horizontal BPPV with apogeotropic nystagmus owed to cupulolithiasis, supine roll test on either side would result in inhibition of the horizontal canal of the lowermost ear because of ampullofugal movement of the cupula and at the same time excitation of the horizontal canal of the uppermost ear because of ampullopetal cupular movement (Fig. 4). Vectorial summation would result in an intense symmetric apogeotropic nystagmus. In both cases, the nystagmus would be more intense than in unilateral horizontal canal involvement because of the additional excitation of the uppermost horizontal canal. To summarize, bilateral horizontal canal BPPV would manifest as bilateral, intense, probably symmetric either geotropic or apogeotropic nystagmus owed to canalolithiasis or cupulolithiasis, respectively. I have found several patients with symmetric geotropic horizontal nystagmus, but in all cases, the side of involvement could be detected by other means, such as the
Fig. 4. Mechanism of cupulolithiasis of bilateral apogeotropic horizontal canal BPPV. Up, Patient in supine position with debris adherent to the cupulae bilaterally. Down, Supine roll test on either side would result in inhibition of the horizontal canal of the lowermost ear, triggering an apogeotropic horizontal nystagmus, and at the same time, excitation of the horizontal canal of the uppermost ear. Vectorial summation would result in intense, more or less symmetric, apogeotropic nystagmus.
Fig. 3. Mechanism of canalolithiasis of bilateral geotropic horizontal canal BPPV. Up, Patient in supine position with debris in the posterior part of both horizontal canals. Down, Supine roll test on either side would result in excitation of the horizontal canal of the lowermost ear and, concurrently, inhibition of the horizontal canal of the uppermost ear. Vectorial summation would result in intense, symmetric geotropic nystagmus.
presence of horizontal pseudonystagmus or the head-down test [21-22]. In addition, performance of the barbecue maneuver on the suspected affected side resulted in remission of the symptoms. It should be finally noticed that the criterion of symmetry of the nystagmus to diagnose bilateral horizontal canal BPPV is not a solid one because asymmetric involvement of the 2 horizontal canals may occur as well, making its diagnosis almost impossible. Involvement of different canals, either on the same side or on both sides, is easier to diagnose. I found 11 such cases (3.2%), including 7 cases with involvement of the posterior and the horizontal canal, either unilaterally (5 cases) or bilaterally (2 cases) and 4 cases of concomitant involvement of the horizontal and the anterior canal (2 bilaterally and 2 unilaterally). I did not find any patients with simultaneous involvement of the posterior and the anterior canal, although this combination has been previously reported [7,20]. Synchronous involvement of the posterior and horizontal canal is a quite common type of mixed vertigo, as has been
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reported in several series, in percentages ranging from 4.4% [23] to 21.2% [24]. Leopardi et al [23], in a multicenter study of 794 patients with BPPV, found 4.4% cases with multiple canal involvement. The authors observed a clear predominance of unilateral forms (posterior and horizontal canals on the same side) but also found several cases of bilateral forms of posttraumatic origin. Moon et al [25], in a multicenter study of BPPV in Korea, found similar results, with multiple canal involvement approaching 5%, with the combination of posterior and horizontal canal being the most common (79.8%). Macias et al [26] found 6.9% of their patients with bilateral involvement (probably of the posterior canal) and 5% with multiple canal involvement, probably of the posterior and horizontal canal variety, because the authors could not at the time of the publication recognize any anterior canal BPPV. In several other reports, larger percentages of multiple canal involvement were found, such as 21.3% in a study of 986 patients with BPPV by Nakayama and Epley [24], who did not provide any specific details about which canals were involved. Lopez-Escamez et al [20], in a study of 80 patients with BPPV, found 14 patients with downbeating positional nystagmus (17.5%), but a detailed study of these cases showed 12 cases of anterior canal BPPV (9 unilateral and 3 bilateral), 1 with horizontal-anterior canal and 1 with posterior-anterior canal BPPV. Finally, Tomaz et al [7], in a retrospective study of 2345 patients, found 35 cases with multiple canal involvement (1.5%) and 252 cases with bilateral involvement (10.7%), either of the posterior (9.9%) or of the anterior canal (0.8%). It should be noticed, however, that we should be skeptical of the diagnosis of bilateral anterior BPPV, and the authors of the 2 previous studies do not provide any detailed criteria on this issue. Treatment was successful in most patients, and these results agree with most other series [23-26]. Provided that accurate diagnosis has been obtained, treatment with successive CRPs, according to the canals involved, has excellent results, comparable with those of single-canal BPPV treatment [27]. In most cases, 2 to 4 therapeutic sessions were adequate, treating a single involved canal on each session and never both of them. However, in 1 case with mixed posterior and horizontal canal of the apogeotropic type BPPV, 7 sessions were needed because of the difficulty of treating cupulolithiasis of the horizontal canal, which usually needs repeated performance of the maneuvers. Cupulolithiasis of the horizontal canal in multiple-canal involvement is quite rare and has been reported only once (canalolithiasis of the posterior canal and cupulolithiasis of the ipsilateral horizontal canal) [28]. Finally, it should be noticed that traumatic origin is quite common in mixed canal BPPV, as previously reported [1,7,29]. In this material, head and neck trauma accounted for mixed BPPV in 11 patients (34.3%), as compared with the percentage of 7% in a singlecanal BPPV group. The issue of differential diagnosis of BPPV from various central vestibular disorders should be also briefly discussed.
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The most significant central causes include central positional vertigo, transient vertebrobasilar ischemia, and migrainous positional vertigo. Several central positional vertigo syndromes have been described, characterized mainly by prolonged nystagmus, usually downbeating, vertigo, and vomiting [30]. All central forms of positional vertigo involve the region around the vestibular nuclei and a neural loop to the cerebellar vermis. Probably, the most helpful features in differential diagnosis from peripheral BPPV is atypical nystagmus, prolonged vertigo, frequent vomiting, and usually absence of latency, fatiguability, and habituation on repetitive stimulation. In addition, brain imaging studies may reveal lesions dorsolateral to the fourth ventricle and of the dorsal vermis, such as tumors, hemorrhages, infarctions, or multiple sclerosis. Transient vertebrobasilar ischemia may be attributed to a functional compression of the vertebral artery, especially in elderly patients with atheromas, cervical spondylosis, or osteophyta that narrow the transverse foramina. During rotational head motion, transient ischemic vertiginous attacks may be induced, which terminate when the head is returned to a normal upright position. Differential diagnosis may be obtained from the clinical manifestations, which besides the vertigo and, occasionally, accompanying nystagmus, may include diplopia, field defects, visual illusions, dysphagia, dysarthria, drop attacks, or motor symptoms. Finally, migrainous vertigo mimicking BPPV (especially of the horizontal canal) may also occur [31]. Useful features in differential diagnosis of migrainous positional vertigo include short-duration symptomatic episodes and frequent recurrences of at least moderate intensity, manifestation early in life, migrainous symptoms during episodes with positional vertigo, atypical positional nystagmus, and failure of treatment by CRPs. In conclusion, in multiple canal BPPV, several difficult diagnostic and treatment issues arise. However, accurate diagnosis based on the nystagmus features of the involved canals leads to the appropriate choice of CRPs, resulting thus to successful treatment of the disorder. References [1] Katsarkas A. Benign paroxysmal positional vertigo (BPPV): idiopathic versus post-traumatic. Acta Otolaryngol 1999;119:745-9. [2] Korres SG, Balatsouras DG. Diagnostic, pathophysiologic, and therapeutic aspects of benign paroxysmal positional vertigo. Otolaryngol Head Neck Surg 2004;131:438-44. [3] Parnes LS, Agrawal SK, Atlas J. Diagnosis and management of benign paroxysmal positional vertigo (BPPV). CMAJ 2003;169:681-93. [4] Uno A, Moriwaki K, Kato T, et al. Clinical features of benign paroxysmal positional vertigo. Nippon Jibiinkoka Gakkai Kaiho 2001; 104:9-16. [5] Korres S, Riga M, Balatsouras D, et al. Benign paroxysmal positional vertigo of the anterior semicircular canal: atypical clinical findings and possible underlying mechanisms. Int J Audiol 2008;47:276-82. [6] Lopez-Escamez JA, Molina MI, Gamiz M, et al. Multiple positional nystagmus suggests multiple canal involvement in benign paroxysmal vertigo. Acta Otolaryngol 2005;125:954-61.
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