Laryngeal and pharyngeal dysfunction in horses homozygous for hyperkalemic periodic paralysis

Elizabeth A. Carr, Sharon Spier, Gregg D. Kortz, Eric P. Hoffman

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


Objective - Evaluate histories, clinical signs, and laboratory data of 69 horses homozygous by DNA testing for hyperkalemic periodic paralysis (HPP). Design - Cohort study. Sample Population - 69 of 189 horses testing homozygous for HPP between October 1992 and November 1994. Procedure - Questionnaires addressing signalment, training regimes, medical history, and current status of affected horses were sent to owners, trainers, or attending veterinarians. Data from completed questionnaires were tabulated and evaluated, using descriptive statistics. Results - Sixty-nine (37%) of 189 questionnaires were completed and returned. Clinical episodes of muscle weakness or paralysis varied in severity and frequency from mild muscle fasciculations to recumbency and death. Sixty-three of 68 HPP-affected horses were reported to have had stridor associated with exercise, excitement, stress, or episodes of muscle paralysis. Common endoscopie findings in affected horses included pharyngeal collapse, pharyngeal edema, laryngopalatal dislocation, and laryngeal paralysis. Twelve of 27 horses receiving acetazolamide had decreases in stridor while receiving medication. Clinical Implications - Most horses testing homozygous for HPP had clinical signs associated with pharyngeal and laryngeal dysfunction. Hyperkalemic periodic paralysis should be included on a differential list for horses examined for signs of laryngeal or pharyngeal dysfunction or stridor. Treatment with acetazolamide may help to control respiratory tract signs associated with this disease.

Original languageEnglish (US)
Pages (from-to)798-803
Number of pages6
JournalJournal of the American Veterinary Medical Association
Issue number4
StatePublished - Aug 15 1996

ASJC Scopus subject areas

  • veterinary(all)


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