ABSTRACT
Hyperthermia leads to increased cardiac output, concurrent hypoxia due to increased metabolic demands, decreased systemic vascular resistance, and hypovolemia, secondary to dehydration. The primary difference between pyrogenic and nonpyrogenic hyperthermia is the presence or absence of a fully functional thermoregulation mechanism. Mortality rates seem proportional to duration and intensity of the hyperthermia and the time required to achieve normothermia. Dogs who survive may have permanent damage to thermoregulatory systems or permanent nephrologic injury, resulting in a predisposition to hyperthermia and diabetes insipidis. Clinically, malignant hyperthermia (MH) is characterized by a rapid onset of tachycardia, hyperthermia, muscle rigidity, tachypnea with progression to dyspnea, and finally apnea. Symptomatic care, as with other forms of hyperthermia, is necessary. Rapid cessation of inhalant anesthesia, changing the anesthetic machine to a “clean” machine, administration of 100% oxygen, and body cooling are all methods used to diminish the effects of MH.
