Hypothermia is defined as a condition of body temperature lower than 95 degrees Fahrenheit. Hypothermia is classified as mild (90 to 95 degrees Fahrenheit), moderate (82.4 to 90 degrees Fahrenheit) and severe (below 82.4 degrees Fahrenheit).
As expected, hypothermia occurs more frequently in cold climates but can also occur in more moderate climates during cold weather especially among the elderly and can be related to exposure to a cold environment. To a lay person, cold temperature is the best-known cause of hypothermia. For physicians, metabolic causes are the more commonly seen causes of hypothermia. In fact, hypothermia is associated with many conditions in addition to environmental exposure, including drugs, alcohol, toxins, burns/skin excoriation, hypoglycemia, malnutrition, coma, sepsis, and uremia.
Hypothermia is not necessarily a fatal condition. Mild hypothermia may be associated with increased respiratory rates, increased heart rates and increased urine output. Moderate hypothermia has been associated with decreased heart rates, decreased respiratory rates, decreased renal blood flow, decreased urine output and abnormal heart rhythm. Severe hypothermia is associated with heart failure and fatal cardiac arrhythmias, decreased renal blood flow, as well as decreased urine output, among other sequellae. Again, the effects of mild hypothermia are markedly different from those of moderate to severe hypothermia.
Although hypothermia may result solely from cold temperature overcoming the ability to rewarm (referred to as primary hypothermia) this diagnosis implies that there is normal ability of the body to rewarm itself by the usual thermostatic mechanisms. Hypothermia caused by the failure of thermostasis, which is the body’s ability to maintain proper temperature (secondary hypothermia), is very common in a variety of conditions. Hypothermia is a very common feature of sepsis and is, in fact, one of the diagnostic criteria for that condition. Hypothermia is also commonly seen in patients with renal failure.
Hypothermia medical expert witness specialties include forensic pathology, nephrology, addiction psychiatry, endocrinology, nutrition medicine, and nephrology.