Audiologic findings in botulism poisoning.
Botulism poisoning results in a presynaptic failure of neuromuscular transmission, and may be expected to impair Eustachian tube and stapedius reflex function. The audiologic findings in five normal-hearing patients with type A botulism poisoning are presented. Results were varied. Two patients demonstrated type B or C tympanograms during the early stages, while three with normal middle ear function demonstrated marked bilateral or unilateral stapedius reflux threshold elevation. One patient had a reversible reflex decay, and the superimposition of a second stimulus upon the first resulted in complete recovery of reflex amplitude. A number of possible pathophysiological mechanisms are discussed.
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Division of Otolaryngology, University of British Columbia, St. Paul's Hospital, Vancouver, Canada.
D000158:Acoustic Impedance Tests; D000328:Adult; D001309:Auditory Threshold / Q000502:physiology*; D001906:Botulism / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D010034:Otitis Media with Effusion / Q000209:etiology; D012022:Reflex, Acoustic / Q000502:physiology*; D013198:Stapedius / Q000503:physiopathology