Hyperthermia is a challenging condition as many dogs present as outwardly healthy. Affected dogs develop signs primarily in response to chemical triggers, worsened by stress. Symptoms include: hypercapnea, tachycardia, and hyperthermia during general anesthesia, progressing to: cardiac dysrhythmia, rhabdomyolysis, renal failure, and death. Although thought to be uncommon, it is difficult to estimate because dogs appear normal until exposed to a trigger, and may die before diagnosis.