Suspected Malignant Hyperthermia after Halothane Anesthesia in a Cat |
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| Authors: | JAMIE R BELLAH DVM DiplomateACVS SHEILAH A ROBERTSON BVMS PhD MRCVS CLAUS D BUERGELT DVM PhD DiplomateACVP A DONALD McGAVIN MVSc PhD DiplomateACVP |
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| Institution: | Departments of Surgical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida;Medical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida;Comparative and Experimental Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida;Department of Pathobiology. College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee. |
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| Abstract: | A 6 month old domestic shorthaired cat died of suspected malignant hyperthermia. Anesthesia was induced and maintained with halothane vaporized in oxygen and nitrous oxide, after acepromazine premedication. Before an incision was made, the cat's heart rate dropped from 140 to 90 beats/min concomitant with a drop in blood pressure. Glycopyrrolate administration resulted in severe ventricular tachycardia (340 beats/min). Halothane and nitrous oxide were discontinued and the surgery was abandoned. Lidocaine administration resulted in a normal sinus rhythm. In recovery, the cat was tachypneic and struggling, with a rectal temperature of 40.1°C that quickly increased to 41.4°C. While the cat was being cooled, cardiac dysrhythmias progressed to ventricular fibrillation that was not responsive to cardiorespiratory resuscitation. Blood specimens obtained while the cat was being cooled showed hyperkalemia (10.0 mEq/L) and increased serum creatine kinase activity (780 IU/L). There was extreme extensor rigidity (rigor mortis) within 5 min of cardiac arrest. Results of microscopic and electron microscopic examination of muscle showed occasional perivascular infiltrates of lymphocytes with infrequent perimysial and epimysial neutrophils and a few sarcomeres with streaming of Z-bands (suggesting a contracted state). Histochemical evaluation of skeletal muscle showed no significant difference between type I and type II fibers. |
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