There are myriad causes of a low body temperature, or hypothermia. Normal body temperature is considered to be approximately 98.6 degrees and is carefully controlled by an area of the brain called the hypothalamus. Under normal circumstances, it causes the body to produce heat by shivering or by increasing the production of epinephrine and thyroxine, which raises the metabolic rate. This temperature control system can be overwhelmed or disabled for a variety of reasons, resulting in hypothermia.
Cold Environmental Conditions
Hypothermia is defined as a body temperature lower than 95 degrees, according to the CDC. Low body temperature decreases the function of the major organs, including the brain and heart. Sufferers of hypothermia caused by cold environmental conditions may not realize the need to seek shelter because of confusion and lethargy due to brain function deterioration. Other signs include marked shivering, slow or slurred speech, decreased coordination, slow movement, low blood pressure and a weak pulse. Elderly people are more susceptible to hypothermia and can even succumb to it inside a dwelling with a temperature between 60 and 65 degrees, the National Institute on Aging says. The use of alcohol and other intoxicants increases the risk of hypothermia.
Surgery
A number of factors related to surgery contribute to hypothermia. Anyone who is under general anesthesia for longer than 30 minutes is at risk, according to an article titled "Evidence-Based Guidelines for the Prevention of Perioperative Hypothermia" by Shawn S. Forbes, M.D., and colleagues in the October 2009 issue of "Journal of the American College of Surgeons." Anesthesia causes vasodilation and decreases thermoregulatory control, or the brain's ability to control body temperature. Cold temperatures in waiting areas and infusions of cold intravenous, or IV, fluids and blood products can also contribute. The authors suggest actively rewarming hypothermic patients at regular intervals and warming IV fluids with a fluid-warming device. They advise patients to bring warm clothing to the hospital and to tell staff if they feel cold.
Sepsis
Sepsis is a life-threatening, body-wide inflammatory response to an infection in the bloodstream. Cells that fight infection, called cytokines, trigger massive inflammation. This can lead to widened blood vessels throughout the body and the formation of clots in small blood vessels inside organs, resulting in low blood pressure and organ damage. The patient with sepsis can have a high or low body temperature, according to The Merck Manual of Medical Information. Other symptoms include a high white blood cell count, rapid heart rate and breathing, low blood pressure and the presence of bacteria in the blood. Hypothermia associated with sepsis is an indicator of a poor outcome. Each year 90,000 people in the U.S. die from sepsis. Sepsis most commonly results from infections acquired while hospitalized, Merck says. Early recognition and prompt treatment are essential.
References
- Surgical-Tutor.org.UK: Perioperative Hypothermia
- National Institute on Aging: Hypothermia: A Cold Weather Hazard
- Centers for Disease Control and Prevention: Hypothermia-Related Deaths --- United States, 1999--2002 and 2005
- American Family Physician: Diagnosis and Treatment of Hypothermia
- The Merck Manual of Medical Information, Second Home Edition: Sepsis and Septic Shock
