Disclaimer: The information contained within the Grand Rounds Archive is intended for use by doctors and other health care professionals. These documents were prepared by resident physicians for presentation and discussion at a conference held at Baylor College of Medicine in Houston, Texas. No guarantees are made with respect to accuracy or timeliness of this material. This material should not be used as a basis for treatment decisions, and is not a substitute for professional consultation and/or peer-reviewed medical literature. The Diagnosis and Management of Perilymphatic Fistulas A perilymphatic fistula is an abnormal communication between the inner ear fluids and the middle ear. Perilymphatic fistulas can be classified into four broad categories: iatrogenic, traumatic, spontaneous, and congenital. Symptoms of perilymphatic fistula are variable and include sensorineural hearing loss, vertigo, dysequilibrium, unsteadiness, motion intolerance, tinnitus and aural fullness. Simmons in 1968 first postulated that sensorineural hearing loss could result from intracochlear membrane breaks. In 1971 Goodhill stated that the labyrinth is hydrostatically loaded with intimate relations to hydrodynamic forces in the carotid arterial system, intracranial venous-sinus systems and the CSF pressure gradients in the subarachnoid space. He proposed that the membranous labyrinth could be ruptured by an explosive route via the external auditory canal and eustachian tube and concluded that membrane ruptures could occur throughout the membranous labyrinth with both acoustic and/or vestibular system sequelae. Simmons later expounded on his original theory and proposed the "double membrane break theory" in the development of sensorineural hearing loss. In this theory he postulated that the second membrane break was the result of a pressure gradient created by the first break, profound sensorineural hearing loss resulted from the mixing of perilymph and endolymph, healing of intracochlear breaks halts the mixing of fluid and the widespread hearing loss disappears resulting in hearing loss at the specific site where local tissue damage occurred along the membrane. The diagnosis of perilymphatic fistula is very difficult to make since there is no diagnostic test for this disorder. The diagnosis depends upon a high degree of clinical suspicion and ruling out other possible causes for the symptoms. In addition to the hearing loss, vestibular dysfunction, tinnitus and aural fullness, patients may also have recruitment, the Tullio phenomenon and a positive fistula test. Evaluation of these patients should include a careful history and physical examination, audiogram, electronystagmography, fistula test, imaging to rule out an intracranial tumor and exclusion of other possible causes for the symptoms (i.e., autoimmune diseases, vascular diseases, infectious diseases and endolymphatic hydrops). The treatment of suspected perilymphatic fistulas is controversial as are most aspects of this disorder and consists of conservative medical therapy or surgical exploration and closure of the fistula. Medical therapy consists of strict bed rest, head elevation, and refraining from all strenuous activity. Some authors advocate this treatment for all cases of suspected perilymphatic fistula if the patient presents early in the course of the disease, whereas others use it to treat patients with symptoms consistent with a perilymphatic fistula but no antecedent history of trauma or surgery. After 5 to 7 days, the patients are re-evaluated and if symptoms persist, surgical exploration is undertaken. Surgical treatment consists of a middle ear exploration and careful examination of the oval and round window niches, looking for crystal clear fluid that persistently wells up after careful suctioning. Special maneuvers such as trendelenburg, internal jugular vein compression and valsalva may be required to adequately visualize a fistula. In addition to fistulas of the oval and round windows, fistulas can also develop from microfissures around the oval and round windows as well as from Hyrtl's fissure and the fissula ante fenestram. Most authors agree that whether a fistula is found or not, a tissue seal with fat, fascia, perichondrium or loose areolar tissue should be made around both the oval and round windows since there is a possibility that the fistula is only intermittently patent or is too small to be visualized. Some authors feel that surgery as an initial form of therapy is indicated in all patients with symptoms for greater than one month, whereas others would proceed only if there is a clear antecedent history of trauma or surgery associated with the typical symptoms of perilymphatic fistula. There are several large studies reporting the results of surgical treatment of perilymphatic fistulas. The percentage of patients with fistulas found surgically ranges from 24% to 93%. Vestibular symptoms had the best response to surgical treatment, with 60% to 90% of cases improving. Hearing loss responded much less favorably except in fluctuating or progressive sensorineural hearing loss in which case surgery would often stabilize or slightly improve the hearing. Postoperative management consists of bed rest, head elevation and no straining for the first 5 days, followed by 4 to 6 weeks of light, non-strenuous activity. The objective assessment of treatment results awaits the development of an objective test for diagnosing perilymphatic fistulas. Case Presentation A 59-year-old white man presented to the VAMC Otolaryngology Clinic 4 days after he developed sudden right hearing loss. The hearing loss developed shortly after he sneezed and was associated with a headache. He denied vestibular symptoms, otalgia, fever or a history of otologic surgery. His past medical history was unremarkable except for left hearing loss of probable sudden onset in 1976 for which he was extensively evaluated while in the Navy. Physical examination was unremarkable and significant laboratory findings included a ESR of 3 mm/hr, rheumatoid factor < 30, negative ANA, nonreactive RPR and mildly elevated liver function tests. Audiogram obtained on admission revealed a profound SNHL on the left with no word discrimination and moderate to severe mixed hearing loss on the right with 35% word discrimination. Tympanograms were type A. The patient was admitted to the VAMC hospital for bed rest and treated with carbogen, intravenous steroids and diuretics. MRI scan of the brain, posturography, and fistula test were all negative. Because the patient's history was suggestive for a perilymphatic fistula, exploratory tympanotomy was performed on the second hospital day. At surgery, clear fluid was noted to collect around the oval window niche consistent with a perilymphatic fistula. Both windows were sealed with loose areolar tissue and the patient recovered unremarkably. A repeat audiogram obtained 2 months after surgery revealed a 10 dB improvement in the PTA and a 10% improvement in speech discrimination score on the right side. Bibliography Allen GW. Fluid flow in the cochlear aqueduct and cochlea - hydrodynamic considerations in perilymph fistula, stapes gusher, and secondary endolymphatic hydrops. Am J Otol 1987;8:319-322. Althaus SR. Perilymph fistulas. Laryngoscope 1981;91:538-562. 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Minute perilymph fistulas: vertigo and Hennebert's sign without hearing loss. Ann Otol Rhinol Laryngol 1979;88:153-159. Lehrer JF, Poole DC, Sigal B. Use of the glycerin test in the diagnosis of post-traumatic perilymphatic fistulas. Am J Otolaryngol 1980;1:207-210. Luntz M, Frank I, Yurovitzki I, Berger G, Sadé J. Large perilymph fistulas. Am J Otol 1986;7:282-286. Meyerhoff WL, Pollock KJ. A patient-oriented approach to perilymph fistula. Arch Otolaryngol Head Neck Surg 1990;116:1317-1319. Meyerhoff WL, Yellin MW. Summating potential/action potential ratio in perilymph fistula. Otolaryngol Head Neck Surg 1990;102:678-682. Narula A, Marks NJ. Acoustic trauma and perilymph fistula. J Laryngol Otol 1985;99:909-911. Nomura Y, Hara M, Young Y-H, Okuno T. Inner ear morphology of experimental perilymphatic fistula. Am J Otol 1992;13:32-37. Parell GJ, Becker GD. Results of surgical repair of inapparent perilymph fistulas. Otolaryngol Head Neck Surg 1986;95:344-346. 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Am J Otolaryngol 1985;6:468-470. Seltzer S, McCabe BF. Perilymph fistula: the Iowa experience. Laryngoscope 1986;94:37-49. Shea JJ. The myth of spontaneous perilymph fistula. Otolaryngol Head Neck Surg 1992;107:613-616. Shelton C, Simmons FB. Perilymph fistula: the Stanford experience. Ann Otol Rhinol Laryngol 1988;97:105-108. Shepard NT, Telian SA, Niparko JK, Kemink JL, Fujita S. Platform pressure test in identification of perilymphatic fistula. Am J Otol 1992;13:49-54. Silverstein H. Rapid protein test for perilymph fistula. Otolaryngol Head Neck Surg 1991;105:422-426. Simmons FB. Theory of membrane breaks in sudden hearing loss. Arch Otolaryngol 1968;88:67-74. Simmons FB. Fluid dynamics in sudden sensorineural hearing loss. Otolaryngol Clin North Am 1978;11:55-61. Singleton GT. Diagnosis and treatment of perilymph fistulas without hearing loss. Otolaryngol Head Neck Surg 1986;94:426-429. Singleton GT, Post KN, Karlan MS, Bock DG. Perilymph fistulas: diagnostic criteria and therapy. Ann Otol Rhinol Laryngol 1978;87:797-803. Stroud MH, Calcaterra TC. Spontaneous perilymph fistulas. Laryngoscope 1970;80:479-487. Supance JS, Bluestone CD. Perilymph fistulas in infants and children. Otolaryngol Head Neck Surg 1983;91:663-671. Thompson JN, Kohut RI. Perilymph fistulae: variability of symptoms and results of surgery. Otolaryngol Head Neck Surg 1979;87:898-903. Weider DJ. Treatment and management of perilymphatic fistula: a New Hampshire experience. Am J Otol 1992;13:158-166. Grand Rounds Archive | Department Home page BCM Public | BCM Intranet | Privacy Notices | Contact BCM | BCM Site Map | ©2001-2006 Baylor College of Medicine
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