Hypothermia in Cats
Hypothermia is a medical condition that is defined as below-normal body temperature. It has three phases: mild, moderate, and severe. Mild hypothermia is classified as a body temperature of 90 - 99°F (or 32 - 35°C), moderate hypothermia at 82 - 90°F (28 - 32°C), and severe hypothermia is any temperature less than 82°F (28°C). Hypothermia occurs when an animal’s body is no longer able to maintain normal temperature, causing a depression of the central nervous system (CNS). It may also affect heart and blood flow (cardiovascular), breathing (respiratory), and the immune system. An irregular heartbeat, trouble breathing, and impaired consciousness to the point of coma may result.
Symptoms and Types
Hypothermia symptoms vary with the level of severity. Mild hypothermia is evident through weakness, shivering, and lack of mental alertness. Moderate hypothermia reveals characteristics such as muscle stiffness, low blood pressure, a stupor-like state, and shallow, slow breathing. Characteristics of severe hypothermia are fixed and dilated pupils, inaudible heartbeat, difficulty breathing, and coma.
Hypothermia usually occurs in cold temperatures, although newborns may suffer hypothermia in normal environmental temperatures due to lack of body heat. Smaller breeds and very young animals more prone to rapid surface loss of body heat are at higher risk as well, as are old (geriatric) pets. Animals under anesthesia are also at higher risk.
Other factors that may increase risk are diseases of the hypothalamus, the part of the brain that regulates appetite and body temperature, and hypothyroidism, a condition characterized by low levels of the thyroid hormone in the body.
If hypothermia is suspected, your cat's body temperature will be measured with a thermometer, or in severe cases, a rectal or esophageal probe. Irregularities in breathing and heartbeat will also be checked. An electrocardiogram (ECG), which records the electrical activity of the heart, can be used to determine your cat's cardiovascular status.
A urinalysis, along with blood tests, is commonly used to diagnose alternative causes for below normal body temperature and unresponsiveness. These tests may reveal low blood sugar (hypoglycemia), metabolic disorders, primary heart (cardiac) disease. Blood and urine tests may also find unknown anesthetics or sedatives in your cat's system.