Hyperthermia is defined as elevation of the body core temperature above 37.5 degrees Celsius (approximately 100 degrees Fahrenheit). Hyperthermia may become life-threatening when core body temperatures reach levels above 40 degrees Celsius (approximately 104 degrees Fahrenheit). Without documentation of body temperature, hyperthermia is a cause of death that requires both an appropriate historical scenario and exclusion of other possible causes of death. It is thus considered a diagnosis of exclusion in most cases. Documentation of temperature is a standard and mandatory element of vital signs, along with parameters like heart rate, breathing rate, and blood pressure. These are typically done in the ambulance during transport to the hospital and/or upon admission to the hospital. Body temperature is an important parameter because a high or low body temperature can change the differential diagnosis in a patient.
By the time of autopsy examination, body temperature would not be valid because of the large period of time that has elapsed since death. Nonetheless, records documenting an elevated temperature should be sought. An autopsy report indicating only a history of exposure to an elevated ambient temperature does not necessarily mean the body temperature had been sufficiently elevated. Aside from attempting to document body temperature, it is also necessary to attempt to document autopsy findings that may support/counter the diagnosis of hyperthermia and to perform appropriate testing in order to exclude other competing causes of death. In the absence of documented elevated body temperature, it may still be appropriate to indicate that a death is primarily due to complications of an elevated ambient temperature if the history supports that conclusion and there are no other compelling competing causes of death.
Although autopsy findings in a death due to hyperthermia are relatively nonspecific (meaning they may be seen in other types of deaths), common findings should be sought and documented in order to support that conclusion. Specifically, hyperthermia is very commonly accompanied by dehydration because excess sweating exhibited by the body in an attempt to decrease body temperature causes significant water loss. This may be readily documented at autopsy by testing the vitreous fluid for electrolytes. Elevation in sodium content of the vitreous fluid would provide support for a theory of dehydration and, by extension, hyperthermia. Vitreous fluid should be drawn in every case since it is the only fluid that can be used for valid electrolyte studies and glucose levels, and is the ideal fluid for many types of other chemical tests.
Malignant hypothermia death medical expert witness specialties include forensic pathology, EMT, emergency medicine, and pediatric emergency medicine.