Heatstroke

Heatstroke is the result of an elevation in the body temperature secondary to an excessive exterior heat (ex. in a car in the sun, in extreme summer heat) or an inadequate evacuation of heat (from vigorous exercise). Dogs are mainly affected, especially brachycephalic breeds (flat nose), those who are overweight and those with a very thick or dark coat.

The elevation in body temperature may lead to a generalized cellular necrosis. It also causes the activation of inflammation mediators. Like this damage is induced as much by the direct heat as by the inflammatory system. Complications such as disseminated intravascular coagulation, damage to the neurons and cerebral edema (possibly causing seizures), bone marrow dysfunction, acute renal insufficiency, necrosis of the intestinal mucosa ( possibly leading to an endotoxemia from the passing of bacteria in the blood), a hypoglycemia, cardiac arrhythmia, damage to the hepatobiliary system (liver) and muscular lesions may be observed.

The clinical signs observed with a heatstroke include excessive panting, an inability to get up, vomiting, diarrhea, convulsions and shaking. Upon physical examination, the rectal temperature is generally above 40°Celcius, the mental state is altered, the mucosa are hyperemic (darker than normal), there may be the presence of respiratory distress and petechiae. A complete physical examination, blood profile, coagulation profile and a urine analysis allows us to evaluate the extent of the damages.

The goal of treatment is to reduce the core body temperature to an acceptable level, to detect and manage the complications. The animal suffering from a heatstroke is in a critical state. The prognosis is very variable, depending on the severity of the clinical signs upon presentation, the presence of complications and the response to treatment. It is very important to act fast when we suspect a heatstroke. Therefore, it can be beneficial to quickly cool the animal down at home before bringing it in to the clinic (using cold, wet towels or a cold bath if the state of conscience is not altered). The animal will be kept in intensive care with fluid therapy where we can monitor his body temperature, blood pressure, test for potential heart arrhythmias (with an ECG) or we can also measure urine production and follow blood parameters. Treatments for shock, acute renal failure, cerebral edema, ventricular arrhythmia, disseminated intravascular coagulation, hemorrhagic diarrhea, septicemia and convulsions will be carried out as needed.