Hypothermia

Related Terms

Body temperature, cardiac arrest, chills, coma, frostnip, heat loss, hypothermic, low body temperature, shivering, uncontrolled shivering.

Background

Hypothermia is a potentially life-threatening condition that occurs when a person's internal body temperature is less than 95 degrees Fahrenheit. Normal body temperature is about 98.6 degrees Fahrenheit. When hypothermia occurs, the body loses heat faster than it is able to produce heat.
Hypothermia is typically caused by prolonged exposure to cold air or cold water. Individuals who participate in winter activities, such as skiing, snowboarding, sledding, ice skating, ice fishing, and hunting, have an increased risk of experiencing hypothermia. Homeless and elderly individuals are also more likely to develop hypothermia.
Severe hypothermia (when the body temperature is 90 degrees or less) may lead to coma or cardiac arrest, both of which may be deadly. An estimated 700 Americans die each year from hypothermia, according to secondary sources. Therefore, individuals should receive prompt medical care as soon as symptoms of hypothermia develop. Warning signs of hypothermia generally include uncontrollable shivering, fatigue or exhaustion, slurred speech, disorientation, and a loss of muscle coordination.
With prompt treatment, people can survive hypothermia. Being aware of warning signs of hypothermia and knowing appropriate first aid responses can help reduce the risk of complications.

Signs and symptoms

Most cases of hypothermia develop gradually, and people are not always aware that they may need medical help. However, some cases of hypothermia may develop within minutes. The severity of hypothermia increases as the body temperature decreases.
Common symptoms of hypothermia include uncontrolled shivering, fatigue or exhaustion, slurred speech, disorientation, slowed breathing, cold and pale skin, and loss of muscle coordination. Individuals who experience any of these symptoms should move indoors as soon as possible and seek immediate medical treatment.

Diagnosis

Hypothermia is diagnosed by a doctor based on the signs and symptoms of the patient, and treatment is started immediately.
Diagnosis of hypothermia is usually made by measuring body temperature with a special thermometer, such as a rectal thermometer, because conventional thermometers do not record below 94? F. If a patient has hypothermia, body temperature will be below 95?F (35? C).

Complications

Frostnip and frostbite: Frostnip (also called mild frostbite) occurs when part of the body, particularly the fingers, toes, and ears, is less than 50 degrees Fahrenheit. The skin starts to feel numb and appears red or white in color.
If patients experiencing frostnip do not go inside to dry off or warm up, blood flow is reduced and the skin may start to freeze. When this happens, it is called superficial frostbite. The skin is typically white and firm to the touch. Superficial frostbite can cause permanent nerve damage in the affected areas.
If superficial frostbite is not treated, it may develop into deep frostbite. This occurs when the skin becomes yellow-white or blue-white in color and the tissues below the skin become frozen. Deep frostbite may lead to tissue death in the affected areas. Dead tissue may then be surgically removed and may require the amputation of affected body parts.
Chilblains: Some people may experience a reaction, called chilblains, when they are exposed to cold temperatures. This is an uncommon reaction that occurs when the small blood vessels in the skin become inflamed in response to cold or cool temperatures. The fingers, toes, ears, and face, are most commonly affected. The skin typically becomes red, and it may also itch or burn for hours after exposure. In some cases, patients may develop open sores or blisters after exposure to the cold.
Researchers have not discovered exactly why some people are sensitive to cold temperatures. Experts believe that these individuals may have unique proteins in their blood that cause the reaction.
Coma, cardiac arrest, and death: Severe hypothermia (when the body temperature is 90 degrees or less) may lead to coma or cardiac arrest, both of which may be deadly. Individuals with severe hypothermia must receive prompt medical attention in order to avoid these complications.

Treatment

General: If a person exhibits signs of hypothermia, call 911 for medical assistance. Until help arrives, individuals should begin first aid to help raise the person's body temperature.
First aid: The person should be brought indoors and out of the cold. This helps reduce additional heat loss.
If the person cannot be moved out of the cold, try to shield him/her from the wind and cold as best as possible. In such cases, individuals should get into the heat escape lessening position (HELP). The person sits with his/her knees bent upwards so they are against the person's chest. This helps minimize heat loss because the legs help keep the person's trunk warm.
Any wet clothing should be removed because they cause the person to lose more heat. Dress or cover the person in dry clothing or blankets. It is especially important to cover the head because it contains a large proportion of the body's blood volume and loses heat more quickly than the rest of the body.
Do not lay the person directly on the ground. Instead, lay the person face up on a blanket, bed, couch, or other warm surface.
Sharing body heat may help increase the patient's body temperature. An individual can remove his/her own clothing and lay next to the patient so their skin is touching. Then, both individuals can cover themselves up with a dry blanket.
Do not apply direct heat to the patient. This means heating pads, heating blankets, hot water bottles, and heating lamps should be avoided. Instead, apply warm (not hot) compresses to the neck, groin, and chest to help increase the patient's body temperature. Do not try to warm the arms or legs because this forces cold blood back toward the lungs, heart, and brain, causing the body temperature to drop even more.
Providing warm beverages, such as hot chocolate or decaffeinated tea, may help increase the person's internal body temperature. Do not give the person caffeine or alcohol because they may worsen his/her condition.
Pay close attention to the person's breathing. In severe cases, individuals may start to breathe slowly or lose consciousness. If this occurs, individuals should begin cardiopulmonary resuscitation (CPR) immediately if they are trained to do so.
Do not rub or massage the person. Individuals should be handled with care because they are at risk of cardiac arrest.
Intravenous (IV) fluids: Once the patient is taken to a nearby hospital, a doctor may give the person warm fluids intravenously. This helps increase the patient's body temperature.
Hemodialysis: A medical procedure, called hemodialysis, may be performed in severe cases of hypothermia. Hemodialysis is usually used to filter the blood in patients with kidney failure. In patients with severe hypothermia, blood is removed, warmed, and then returned to the patient.

Integrative therapies

Note: Currently, there is a lack of scientific data on the use of integrative therapies for the treatment or prevention of hypothermia. Most of the integrative therapies listed below have been used traditionally or theoretically to treat a related condition, called frostbite. Hypothermia is a serious and potentially life-threatening condition that requires urgent medical treatment. Patients should not use integrative therapies in place of well-established medical treatments for hypothermia.
Unclear or conflicting scientific evidence:
Thiamin: Thiamin (also spelled "thiamine") is a water-soluble B-complex vitamin. It is also known as vitamin B1 or aneurine. Administration of thiamin is often recommended in patients with coma or hypothermia of unknown origin, due to the possible diagnosis of Wernicke's encephalopathy.
Thiamin is generally considered safe and relatively nontoxic. Avoid if allergic or hypersensitive to thiamin. Rare hypersensitivity/allergic reactions have occurred with thiamin supplementation. Skin irritation, burning, or itching may rarely occur at injection sites. Large doses may cause drowsiness or muscle relaxation. Use cautiously if pregnant or breastfeeding.
Traditional or theoretical uses lacking sufficient evidence:
Aloe vera: Clear gel from the pulp of Aloe vera leaves has been used on the skin for thousands of years to treat wounds, skin infections, minor burns, and other skin conditions. Limited laboratory evidence suggests that topical aloe may help treat the effects of frostbite. However, until well-designed studies are performed in humans, it remains unknown if this is a safe and effective treatment.
Avoid if allergic to aloe or other plants of the Liliaceae family (garlic, onions, tulips). Avoid injecting aloe. Avoid applying to open surgical wounds or pressure ulcers. Avoid taking by mouth with diarrhea, bowel blockage, intestinal diseases, bloody stools, hepatitis, irregular heartbeat, electrolyte imbalances, diabetes, heart disease, or kidney disease. Avoid taking by mouth if pregnant or breastfeeding.
Bitter orange: Bitter orange (Citrus aurantium) comes from a flowering, fruit-bearing evergreen tree native to tropical Asia. It is now widely grown in the Mediterranean region and elsewhere. It remains unclear if bitter orange can help treat frostbite. Well-designed studies are needed to evaluate its safety and effectiveness.
Avoid if allergic or hypersensitive to bitter orange or any members of the Rutaceae family. Avoid with preexisting heart disease, narrow-angle glaucoma, or intestinal colic. Avoid if taking anti-adrenergic agents, beta-blockers, or QT-interval prolonging drugs, antidepressants, stimulants, or honey. Avoid with long QT interval syndrome. Use bitter orange preparations that are applied to the skin cautiously with fair skin. Use cautiously with headache and hyperthyroidism. Avoid if pregnant or breastfeeding.
Bromelain: Classified as an herb, bromelain is a digestive enzyme that comes from the stem and the fruit of the pineapple plant. Although bromelain has been suggested as a possible treatment for frostbite, scientific evidence is lacking in this area.
Avoid if allergic to bromelain, pineapple, honeybee, venom, latex, birch pollen, carrots, celery, fennel, cypress pollen, grass pollen, papain, rye flour, wheat flour, or other members of the Bromeliaceaefamily. Use cautiously with a history of bleeding disorders, stomach ulcers, heart disease, or liver or kidney disease. Use cautiously before dental or surgical procedures or while driving or operating machinery. Avoid if pregnant or breastfeeding.
Calendula: Calendula, also known as marigold, has been widely used on the skin to treat minor wounds, skin infections, burns, bee stings, sunburn, warts, and cancer. Traditionally, calendula has been used to treat frostbite. However, studies have not evaluated the safety and effectiveness of this therapy.
Avoid if allergic to plants in the Aster/Compositae family such as ragweed, chrysanthemums, marigolds, and daisies. Use cautiously in patients taking sedatives, blood pressure medications, cholesterol medications, blood sugar-altering agents, or immunomodulators. Use cautiously with diabetes and in children. Avoid if pregnant or breastfeeding.
Chamomile: Chamomile is an herb that has an apple-like smell and taste. It is commonly ingested as a tea. It has been suggested, but not proven, that chamomile may help treat frostbite.
Avoid if allergic to chamomile. Anaphylaxis, throat swelling, skin allergic reactions, and shortness of breath have been reported. Chamomile eyewash may cause allergic conjunctivitis (pinkeye). Stop use two weeks before and immediately after surgery/dental/diagnostic procedures with bleeding risks. Use cautiously if driving or operating machinery. Avoid if pregnant or breastfeeding.
Hawthorn: Hawthorn, a flowering shrub of the rose family, has an extensive history of use for heart disease, dating back to the first Century. It has been suggested that hawthorn may help treat frostbite, but studies have not determined if this claim is true.
Avoid if allergic to hawthorn or to members of the Crataegus genus. Avoid with a history of low blood pressure, irregular heartbeat, asthma, low blood pressure when standing, or insomnia. Use cautiously in elderly patients. Avoid if pregnant or breastfeeding.
Horsetail: Horsetail is a descendant of the giant fern-like plants that covered the earth 200 million years ago. It has been proposed that horsetail may help treat frostbite. Until trials are performed in humans, it remains unclear if this is a safe and effective therapy.
Avoid if allergic or hypersensitive to horsetail or nicotine. Avoid with a history of chronic alcohol abuse, malnutrition, or kidney disorders. Use cautiously with abnormal heart rhythms, diabetes, gout, neurological disorders, or osteoporosis. Avoid in children. Avoid if pregnant or breastfeeding.
Schisandra: Schisandra berries are called "five-flavor fruit," based of their salty, sweet, sour, pungent, and bitter flavors. The dried fruit is formed into powder, tinctures, and wine, and used in capsules and teas either as a single ingredient or in combination products. Schisandra has been suggested as a possible treatment for frostbite. However, evidence is currently lacking in this area.
Avoid if allergic or sensitive to schisandra. Skin rashes and hives have been reported.
Sea buckthorn: Sea buckthorn (Hippophae rhamnoides) is found throughout Europe and Asia, particularly eastern Europe and central Asia. It has been suggested that sea buckthorn may help treat the effects of frostbite. However, scientific studies are lacking in this area.
Avoid if allergic or hypersensitive to sea buckthorn, its constituents, or members of the Elaeagnaceae family. Use cautiously in patients with cancer, high blood pressure, or bleeding disorders. Avoid doses higher than those found in foods if pregnant or breastfeeding.
Vitamin E: Vitamin E exists in eight different forms ("isomers"): alpha, beta, gamma, and delta tocopherol; and alpha, beta, gamma, and delta tocotrienol. Alpha-tocopherol is the most active form in humans. Theoretically, vitamin E may help treat frostbite. However, a firm conclusion cannot be made until well-designed studies are performed.
Avoid if allergic or hypersensitive to vitamin E. Avoid with retinitis pigmentosa (loss of peripheral vision). Use cautiously with bleeding disorders or if taking blood thinners. Avoid doses greater than the recommended daily level in pregnant women and breastfeeding women.

Prevention

Wear protective clothing, such as jackets, hats, mittens/gloves, and scarves, when exposed to cold temperatures. Wearing layers of clothing helps insulate the body. It is especially important to cover the head because it contains a large proportion of the body's blood volume and loses heat more quickly than the rest of the body.
Avoid activities that may cause sweating in cool or cold temperatures. Sweating in such temperatures may cause chills and increase the risk of hypothermia.
Stay as dry as possible. Replace wet clothes with dry clothes as soon as possible.
Wear a life jacket when riding in a boat or watercraft.
Know the warning signs of hypothermia in order to help prevent serious, life-threatening complications. Individuals should go indoors and seek help if they are experiencing early signs of hypothermia.
Learn the appropriate first aid response for hypothermia. Knowing how to take care of someone with hypothermia increases the chance of survival.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

Bangs CC. Hypothermia and frostbite. Emerg Med Clin North Am. 1984 Aug;2(3):475-87.
Biem J, Koehncke N, Classen D, et al. Out of the cold: management of hypothermia and frostbite. CMAJ. 2003 Feb 4;168(3):305-11.
Britt LD, Dascombe WH, Rodriguez A. New horizons in management of hypothermia and frostbite injury. Surg Clin North Am. 1991 Apr;71(2):345-70.
Centers for Disease Control and Prevention (CDC). .
National Institutes of Health (NIH). .
Natural Standard: The Authority on Integrative Medicine. .
[No authors listed.] [Hypothermia and frostbite. First measures for victims of cold.] [Article in German.] MMW Fortschr Med. 2005 Apr 7;147(14):6, 8.
Wittmers LE Jr. Pathophysiology of cold exposure. Minn Med. 2001 Nov;84(11):30-6.

Causes

Exposure to cold temperatures: Hypothermia is typically caused by prolonged exposure to cold temperatures. It does not always occur in the winter months. It may occur if the weather is exceptionally cold in the fall or early spring. The wind chill factor should also be taken into consideration.
In some cases, exposure does not have to be prolonged. For instance, if an individual falls through the ice on a body of water he/she may develop hypothermia within minutes to hours (depending on the temperature of the water). The body loses heat more quickly in water than it does in the air. Exposure to water that is colder than the body can potentially decrease the body temperature.
Prolonged exposure to cool or damp temperatures: Hypothermia may be caused by prolonged exposure to cool, damp environments. When water is on the skin and starts to evaporate, a person's body temperature falls. If wind blows over wet skin it increases evaporation and cools the body even faster. For instance, if an individual is outside during a rain shower on a cool day, hypothermia may result if the person does not quickly move inside to warm up and dry off.
Inadequate protective clothing: Not wearing enough protective clothing, such as jackets, hats, mittens/gloves, and scarves, increases the risk of hypothermia. It is especially important to cover the head because it contains a large proportion of the body's blood volume and loses heat more quickly than the rest of the body.