Malignant hyperthermia

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Malignant Hyperthermia

Malignant hyperthermia (MH) is a rare generalized muscle disease in which there is progressive hyperthermia (elevated body temperature due to failed thermoregulation that occurs when the horse's body produces or absorbs more heat than it dissipates), hypercapnia (a condition of abnormally elevated carbon dioxide (CO2) levels in the blood) and muscle rigidity associated with certain anesthetic agents or muscle relaxants.

Horses with the MH mutation may intermittently show signs of tying up and high body temperatures, or they may show no signs at all and die suddenly after an episode of tying up.

Symptoms

Intermittent tying up signs
Body temperature elevation
Sweating
Abnormal heart rhythm
Variable breathing patterns
Sudden death

Diagnosis

  • Clinical signs
  • History
  • Physiical exam
  • Laboratory diagnostics
  • Genetic testing

Treatment

TherapiesDetails
Decrease body temperature
Supportive treatment
Dantrolene sodium

Scientific Research

General Overviews

  • Sweating icon

Commonly Affected Breeds

Quarter Horse iconPaint Horse icon