------------------------------------------------------------------------------- TITLE: Benign Paroxysmal Positional Vertigo SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: 10/26/94 RESIDENT PHYSICIAN: Gregory Young, M.D. FACULTY: Jeffrey Vrabec, M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. ------------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." Benign paroxysmal positional vertigo(BPPV) is one of the most common peripheral vestibular disorders. It generally account for 15 - 40% of patients presenting to the otolaryngologist with dizziness. HISTORICAL INFORMATION: The disorder was first described by Barany in 1921, who reported a group of patients with a rotary sense of disequilibrium associated with various head positions. In 1952, Hallpike and Dix reported on a large series of patients in whom vertigo and nystagmus was elicited from the Hallpike maneuver. The disorder was originally thought to be otolithic in origin, because of its association with positional change. However, studies have since demonstrated that its pathophysiology is based on a change in the motion characteristics of the posterior semicircular canal. Schuknecht in 1969 found basophilic debris adherent to the cupula of the posterior semicircular canal of diseased labyrinths. He postulated that this debris was responsible for the nystagmus and associated symptoms of BPPV, by transforming the posterior semicircular canal into a gravity sensitive organ. Clinical studies on patients with BPPV and severe unilateral hearing loss showed that ablation of either the eighth cranial nerve or the labyrinth resulted in resolution of positional vertigo, indicating that the pathology was located peripherally, rather than centrally. EPIDEMIOLOGY: Although BPPV is the most common cause of vertigo seen by the otolaryngologist, the incidence is difficult to estimate because of its usual benign course and frequent spontaneous resolution. The incidence has been reported to be 10 - 17 per 100,000, although the true incidence is probably higher. The usual age of onset is 30 - 50 years, with a range of 10-85 years. The incidence increases with age, and is somewhat more prevalent in women, with a ratio of 2 females to 1 male. PATHOPHYSIOLOGY: Early temporal bone studies demonstrated utricle degeneration in those patients with BPPV. Schuknecht reported basophilic debris adherent to the cupula of the posterior semicircular canal, and postulated that the debris was the remnants of displaced utricular otoconia. He suggested that the utricular otoconia debris, which he termed cupulolithiasis, floated down into the most dependent portion of the labyrinth, the ampulla of the posterior semicircular canal. These deposits change the response characteristics of the cupula from a purely angular acceleration detector to one that responds to gravity and linear acceleration. Laboratory studies by Money and Myles support the concept that acquisition of gravity sensitive characteristics in the posterior semicircular canal cupula can lead to BPPV. They changed the neutral buoyancy of the cupula by adding alcohol or heavy water to the endolymph, which produced positional nystagmus in laboratory animals. More recent studies by Parnes and McClure demonstrated free-floating particles in the posterior semicircular canal. These particles may, over a period of seconds, build up a hydrodynamic drag on the affected cupula, resulting posterior canal excitation. As these particles become dispersed, the hydrodynamic drag is reduced, and the vertigo subsides. If this theory is true, it helps explain the findings of "latent onset" and "fatigue", characteristic of the vertigo in patients with BPPV. Anatomic and physiologic studies have shown that the observed nystagmus in BPPV is caused by stimulation of the posterior canal excitatory pathways and the complimentary superior canal excitatory pathways. The posterior canal pathways stimulate the ipsilateral superior oblique and the contralateral inferior rectus muscles. The complementary superior canal pathways stimulate the ipsilateral inferior oblique and superior rectus muscles. The fast component of the rotatory vertical nystagmus produced by stimulation of the posterior canal is clockwise upbeat with stimulation of the left posterior canal and counterclockwise upbeat with stimulation of the right posterior canal. Comparing animal models with clinical observations, it has been found that nystagmus associated with BPPV is identical to that produced by posterior canal excitation, and transection of the posterior canal afferent nerve abolishes the nystagmus. DIAGNOSIS: History: Patients with BPPV typically have severe vertigo elicited by a change in head position, often side specific or associated with head extension. The vertigo occurs suddenly, lasting a few seconds, and never more than 1 minute. The episodes tend to occur in clusters, separated by remissions lasting up to months or years. Periods of active disease may be associated with a constant feeling of light-headedness, worsened by head movement. There is no precipitating event in about 50% of cases. However, about 15 - 20 % are preceded by trauma or viral infection. There may be a history of stapedectomy or other surgery requiring general anesthesia, or rarely Meniere's disease or recurrent vestibulopathy. Physical Examination: Hearing is usually normal or at least symmetric. The Hallpike maneuver, which elicits a characteristic nystagmus pattern, is pathognomonic of BPPV. The Hallpike maneuver is performed by positioning the patient on the exam table in the sitting position such that when placed supine, the patient's head extends beyond the end of the table. The patient is lowered into the supine position with the head supported and turned 45 degrees to one side. The patient is instructed to look straight ahead at all times. This position is held for 30 seconds or until the response disappears, during which time the patient's eyes are carefully observed for nystagmus. The patient is then returned to the sitting position. If a response is elicited, the examiner repeats the same maneuver as many times as is necessary to determine if the response fatigues. The maneuver is repeated with the head in the other direction, and then again with the head in the neutral position. Normal individuals have a few beats of nystagmus during the backward movement, but none after the movement is completed. The nystagmus appears when the diseased ear is placed towards the floor. Use of Frenzel's glasses can detect less severe cases of BPPV by preventing visual fixation, which can sometimes suppress peripheral nystagmus. The pathognomonic nystagmus pattern of BPPV consists of: 1) The nystagmus is rotational and geotropic. 2) There is a latency of onset, usually around 1 - 5 seconds. 3) The duration of nystagmus is short, usually 20-30 seconds, and always less than 1 minute. 4) The nystagmus is associated with vertigo, which follows the same time course as the nystagmus. 5) The nystagmus is fatiguable, that is, it becomes progressively weaker and disappears with repeated testing. 6) The nystagmus is reversible with return of the head to the upright position. Fifteen to 20% of patients with BPPV have nystagmus and symptoms in both lateral positions, so-called bilateral BPPV. Rarely, a patient may have horizontal nystagmus rather than rotatory nystagmus, with the same characteristics as described above. This probably represents involvement of the lateral semicircular canal. Not all patients with BPPV have nystagmus or vertigo following the Hallpike maneuver, possibly because the response has been fatigued by natural head movements prior to testing. So, the lack of a response does not rule out BPPV. In addition, it has been shown that patients with disorders other than BPPV may display nystagmus after the Hallpike maneuver, although these patients fail to meet criteria such as latency and fatiguability. Diagnostic Tests: The diagnosis of BPPV can usually be made on the basis of a thorough history and a carefully performed Hallpike maneuver. Occasionally, certain vestibular function tests will be helpful in making the diagnosis. Current electronystagmography(ENG) cannot detect rotational movement, so only the vertical and horizontal components of the torsional eye movements are reflected on the eye tracings. This underscores the need for direct observation of the patient's eyes during the Hallpike maneuver. Differential Diagnosis: Differential diagnosis includes perilymphatic fistula, drug or alcohol intoxication, Meniere's disease, neurovascular compression, Waldenstrom's disease, and psychogenic vertigo. TREATMENT: Non-Surgical Treatment: Spontaneous resolution occurs in most patients within several months of onset of BPPV. This is especially true of BPPV with antecedent head injury. Vestibular suppressants are usually ineffective due to the short lasting, intense nature of the vertigo. Cawthorne advocated vestibular habituation therapy, whereby the patient would repetitively assume the position of maximal stimulation with the affected ear in the dependent position. This was thought to build up tolerance to the stimulus. Liberatory maneuvers have been developed to displace the heavy debris on the cupula away from the ampulla of the posterior semicircular canal. The Brandt maneuver is performed by the patient, and resolution of symptoms is reported in 85% of patients. The Semont maneuver, which is performed by the physician, can be associated with significant nausea, vertigo and instability, lasting up to 2 days. The particle repositioning maneuver, as described by Epley, is thought to relocate free-floating particles from the posterior semicircular canal back into the utricle. Resolution of vertigo symptoms is reported in 84-100% of patients with BPPV. The procedure is performed as follows: After the Hallpike maneuver is performed, the patient sits upright for 10 minutes to allow the particles to accumulate in the most dependent position of the posterior canal. The head is extended over the edge of the table with the affected ear down. The patient is then rotated 180 degrees from the starting position, now with the opposite ear down and the head again pointed toward the floor. In this position, the particles move through the common crus and into the utricle. Once the nystagmus and vertigo have ceased, the patient is again brought into the sitting position and is observed for any residual nystagmus. The patient is then asked to remain upright for the next 48 hours to prevent the particulate matter from reentering the posterior canal. Overall, vestibular exercises tend to relieve vertigo in 80 - 90% of patients with BPPV. Studies have shown that some individuals respond to one type of exercise better than another. A plausible explanation is that some BPPV is caused by free-floating particles and other cases are caused by heavy debris attached to the cupula. This theory is supported by Epley's study in which the particle repositioning maneuver was combined with the use of a bone vibrator. In his group of 30 patients, 100% success was reported. Surgical Treatment: A small number of patients with BPPV do not respond to vestibular exercises. Some of these patients have persistent, near incapacitating symptoms lasting several months and even years. These patients are less likely to experience spontaneous recovery, and may therefore be candidates for operative therapy. Money and Scott, using an animal model, showed that plugging a semicircular canal would block its function without interfering with other vestibular receptors. Occlusion of posterior semicircular canal has been shown to abolish vertigo in patients with BPPV. A transmastoid approach is used. The posterior canal otic capsule is exposed and an endosteal island is created. The endosteal island is lifted out, and a plug composed of fibrinogen glue and mastoid bone chips is placed into the canal. Temporalis fascia and glue are used to cover the plug. Transient sensorineural hearing loss is common and is probably due to a reactive inflammatory serous labyrinthitis. Posterior canal occlusion is gaining popularity in several centers because of its high rate of success ( 95%), predictable anatomy, and relative ease of performing the procedure. Sectioning of the vestibular nerve eliminates afferent and efferent input to the vestibule. A middle cranial fossa approach was popularized by House in the 1970s. This approach is technically demanding, requires temporal lobe retraction, and is limited to younger patients because of increased dural friability and adherence over time. The posterior cranial fossa approaches, retrolabyrinthine and retrosigmoid, are relatively less technically demanding, and are popular in some centers. Both the middle and posterior cranial fossa approaches allow preservation of the cochlear nerve and provide complete control of vertigo in 85 - 95% of patients. However, they require the assistance or at least the availability of a neurosurgeon. Complications include CSF leak, meningitis, hearing loss, and facial paralysis. The vestibular nerve divides into the superior and inferior vestibular nerves near the internal acoustic meatus. The superior vestibular nerve supplies the lateral and superior semicircular canals, as well as the utricle. The inferior vestibular nerve further divides into the saccular nerve which innervates the saccule, and the posterior ampullary nerve, or singular nerve, which innervates the posterior semicircular canal. Transection of the singular nerve, singular neurectomy, results in ablation of BPPV symptoms. An approach through the external auditory canal can be performed with local anesthesia by sectioning the singular nerve near the round window niche. The singular nerve travels in the singular canal. The proximal half of the canal is the canalicular portion, which contains CSF. The distal 1/4 of the canal is the cribose section, where the nerve divides and travels in multiple bony trabeculae surrounded by dense connective tissue. Between the canalicular and cribose portions of the canal is the intermediate portion of the canal, where the nerve travels in loose connective tissue. The intermediate portion is accessible in the round window niche. Transection of the nerve is performed by probing the proximal aperture of the canal with a pick or hook. Vertical downbeat spontaneous nystagmus following completion of surgery confirms ablation of the nerve(this is thought to be a compensatory release nystagmus originating in the cerebellar vermis). Complete ablation of symptoms occurs in 80 - 97% of patients. With this procedure, local anesthesia can be used, and the labyrinth is not violated so recovery is quick. However, post-operative sensorineural hearing loss occurs in 4-6 % of patients, and nystagmus and disequilibrium persist for up to 4 days postoperatively. The main disadvantage of this procedure is that the anatomy is not very predictable. The singular nerve is obscured from view in 20% of cases, making nerve transection difficult or impossible. Labyrinthectomy has been performed on a small number of relatively young patients with BPPV who had severe symptoms and a coexisting deaf ear. ------------------------------------------------------------------------------ BIBLIOGRAPHY Anthony, P.: Partitioning of the labyrinth: application in benign paroxysmal positional vertigo. Am J Otol 12(5):388, 1991. Anthony, P.F.: Partitioning the labyrinth for the treatment of benign paroxysmal positional vertigo. Operative Techniques in Oto-HNS, 3(4): 274, 1992. Bailey, B.J.: Head and neck surgery-otolaryngology, J.B. Lippincott Company, 1993. Baloh, R.W., Honrubia, V., and Jaconson, B.A.: Benign postional vertigo: Clinical and oculographic features in 240 cases. Neurology 37:371, 1987. Brandt, T., Daroff, R.: Physical therapy for benign paroxysmal positional vertigo, Arch Otolaryngol 106: 484, 1980. Brandt, T.: Positional and positioning vertigo and nystagmus. J. Neurolog Sci, 95:3, 1990. Donaldson, J.A., et al: Surgical Anatomy of the Temporal Bone, 4th Ed., Raven Press, 1992. Epley, J: New dimensions of benign positional vertigo. Otolaryngol Head Neck Surg 88: 599, 1980. Gacek, R.R.: Further observations on posterior ampullary nerve transection for postional vertigo. Ann. Otol.Rhinol. 87:300,1978. Gacek, R.: Singular neurectomy update II: review of 102 cases. Laryngoscope 101:855, 1991. Gacek, R.R., Gacek, M.R.: Singular neurectomy in the management of paroxysmal positional vertigo. Otolaryngol Clinics 27:2, 1994. Glasscock, M.E.: Vestibular nerve section, Arch Otolaryngol 97:112, 1973. Glasscock, M.E., Shambauch, G.E.,:Surgery of the ear, 4th ed. W.B. Saunders Company, 1990. Glasscock, M.E., et al,: An analysis of the retrolabyrinthine vs. the retrosigmoid vestibular nerve section, Otolaryngol Head Neck Surg 104(1): 88, 1991. Goycoolea, M.V.: Atlas of otologic surgery. W.B. Saunders Company, 1989. Linstrom, C.J.: Office management of the dizzy patient. Otolaryngol Clinics 25:4, 1992. Moriarty, B., et al., The incidence and distribution of cupular deposits in the labyrinth. Laryngoscope 102, 1992. Paparella, M.M., et al: Otolaryngology, 3rd Ed., W.B. Saunders Company, 1991. Parnes, L.S., Treatment of benign paroxysmal positional vertigo by selective ablation of the posterior semicircular canal. Operative Techniques in Oto-HNS, 3 (1):48, 1992. Parnes, L., McClure, J.: Posterior semicircular canal occlusion for intractable benign paroxysmal positional vertigo. Ann Otol Rhinol Laryngol 99:300, 1990. Schuknecht, H.:Cupulolithiasis. Arch. Otolaryngol. 90:765, 1969. Schuknecht, H.: Pathology of the ear, 2nd Ed., Lea and Febiger, 1993. Semont, A., Freyss, F., Vitte, E.: Curing the BPPV with the liberatory maneuver. Adv Otol Rhinol Laryngol 42:290, 1988. Silverstein, H., Willcox, T.O.,:Vestibular nerve section. Otolaryngol Clinics 27:2, 1994. Welling, D.B., Barnes, D.E.,: Particle repositioning maneuver for benign paroxysmal positional vertigo. Laryngoscope 104, 1994. --------------------------------END------------------------------------------ TEST QUESTIONS - The following test questions are intended to provide proof to accrediting agencies that you have read and understood the entire Grand Rounds element. Your answers should be based on the text of the Grand Rounds element. Answers should be sent by e-mail addressed to fbquinn@utmb.edu. Answers can be sent by U.S Postal Service mail, using a plain sheet of paper on which the Grand Rounds element and the subscriber are fully identified. Correct answers will be transmitted to the subscriber via e-mail on request. Comments and alternative points of view should be expressed at the end of the list of the subscriber's answers. E-mail answers can be submitted thus: Otitis media 1b, 2c, 3b, 4a, 5c, 6b, 7d, 8c, 9a, 10a yes, yes, yes, no, yes, ?, yes, ?, 50 cents The University of Texas Medical Branch (UTMB) is accredited by the Accreditation Council For Continuing Medical Education (ACCME) to sponsor continuing medical education for physicians. UTME designates this continuing medical education activity for 1 credit hour in Category 1 of the Physicians's Recognition Award of the American Medical Association. 1. All of the following are true regarding the epidemiology of BPPV, except: a. usual age of onset is 30-50 years old b. incidence decreases with age c. more prevalent in women d. the most common cause of vertigo seen by the otolaryngologist c. usually follows a benign course with spontaneous resolution 2. The pathognomic nystagmus pattern of BPPV is a. usually horizontal b. 80% bilateral c. usually 20-30 seconds, always less than a minute d. without a latency of onset e. usually stronger as testing is repeated 3. The Hallpike maneuver is characetrized by all of the followine except: a. a positive response is pathognomonic of BPPV b. visual fixation can sometimes suppress peripheral nystagmus c. normal individuals have a few beats of nystagmus during the backward movement, but none after the movement is completed d. it is performed by positioning the patient on the exam table in the sitting position, lowing him/her into the supine position with the head extending beyond the end of the table, supported and turned 45 degrees to one side e. the nystagmus appears when the diseased ear is turned away from the floor 4. All of the following are true concerning the treatment of BPPV except: a. vestibular suppressants are usually very effective b. vestibular habituation therapy helps 80-90% of patients c. particle repositioning maneuvers result in resolution of symptoms in 85-100% of patients d. surgical therapy is rarely required e. transection of the singular nerve (singular neurectomy) results in ablation of BPPV symptoms 5. The differential diagnosis of BPPV includes all the following except: a. perilymphatic fistula b. drug/alcohol intoxication c. Meniere's disease d. neurovascular compression e. otosclerosis 6. Which of the following statements is true? a. ENG is very helpful in making the diagnosis of BPPV b. BPPV accounts for only 1-2% of patients with "dizziness" c. Hearing is usually abnormal in the affected ear d. There is no precipitating event in about 50% of cases e. All patients with BPPV experience nystagmus or vertigo immediately after the Hallpike maneuver 7. BPPV is curently thought to be the result of a. inflammation of the eighth cranial nerve b. otolithic abnormalities c. changes in the motion characteristics of the posterior semicircular canal d. occlusion of the posterior semicircular canal e. electrolyte abnormalities of the middle ear fluid 8. The classic history given by a patient with BPPV includes all the following except: a. severe vertigo elicited by changes in head position b. severe unilateral hearing loss c. vertigo which begins suddenly and lasts a few seconds d. recent head trauma or viral infection e. clusters of vertiginous episodes, separated by remissions lasting months to years 9. Which of the following statements about the pathophysiology of BPPV is false: a. basophilic debris adherent to the cupula of the posterior canal tranform the posterior semicircular canal into a gravity-sensitive organ b. free-floating particles have been demonstrated in the posterior semicircular canal, and these particles may, over a period of seconds, build up a hydrodynamic drag on the affected cupula c. the nystagmusin BPPV is caused by stimulation of the posterior canal excitatory pathways and the complementary superior canal excitatory pathways d. utricular otoconia debris (cupulolithiasis) stimulate free-nerve endings to cause vertigo e. transection of the posterior canal afferent nerve in animal models abolishes the nystagmus 10. All of the following concerning the nonsurgical treatment of BPPV are true except: a. In vestibular habituation therapy, the patient assumes the position of minimal stimulation with the normal ear in the dependent position. b. Epley's particle repositioning maneuver involves having the patient sit upright for 10 minutes, then lie down with the head extended over the end of the table with the affected ear down, then rotating the patient 180 degrees, now with the opposite ear down and the head again pointed toward the floor, and finally returning the patient to the sitting position. c. Libratory meneuvers such as the Brandt or Semont maneuvers, displace the heavy debris in the cupula away from the ampulla of the posterior semicircular canal d. The reason that some patients with BPPV do not respond to vestibular exercises is that some BPPV is caused by free-floating particles and other causes are caused by heavy debris attached to the cupula. e. Due to the short, intense nature of the vertigo in BPPV, vestibular suppressants are largely ineffective. 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Quinn, Jr., M.D. University of Texas Medical Branch Dept. of Otolaryngology Galveston, TX 77555-0521 Internet addresses: 409-772-2706, 772-2701 fbquinn@UTMB.edu 409-772-1715 FAX fbquinn@phil.utmb.edu ==================================================================