Hypothermia
Hypothermia is defined as core body temperature of less than 35 degrees Celsius. It can be divided into mild (temp 32 - 35), moderate (temp 28 - 32) and severe (< 28). It can also be classified as either Primary (exposure hypothermia) or Secondary. The latter is seen in the elderly, ill or intoxicated and will not be discussed here.
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Last Updated on Monday, 21 September 2009 20:36 |
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Frostbite
Frostbite is caused by destruction of the tissues secondary to freezing. It usually occurs at temperatures less than 2 degrees Celcius.
It can be divided into two phases.
- Cooling Injury: Initial response of dilation and constriction of blood vessels in the tissues, followed by formation of tissue ice crystals. The tissue temperature continues to fall, forming ice crystals within the cells and leading to cell death.
- Rewarming Injury: Thawing of the limb leads to small blood vessel damage and formation of clots.
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Last Updated on Sunday, 30 August 2009 21:57 |
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Trench Foot
Trench foot is caused by prolonged exposure to cold (temperature 0 - 20 degrees) and wet environment. Tissue injury is caused by swelling of the skin and damage to the small blood vessels due to water absorption at cold temperatures. It is characterised by numbness, pain, leg cramping, pale and wrinkled soles, blisters, ulcers and gangrene in severe cases. Tissue loss can take months to heal.
Frostnip, chilblains and trenchfoot respond well to rewarming with dry heat. Treatment also consists of elevating the affected part and avoiding manipulation or pressure. Topical antibiotic cream is also useful. |
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Last Updated on Sunday, 30 August 2009 21:57 |
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Frostnip/Chilblain
Frostnip is the mildest form of cold injury. It is caused by cold-induced constriction of the blood vessels. Symptoms include pain and altered sensation. Frostnip resolves with rewarming without causing damage to the skin. It especially affects the fingers, toes and ears.
Chilblains are caused by chronic intermittent exposure to cool (above freezing), wet conditions. Tissue damage is caused by constriction and inflammation of the blood vessels. Symptoms include itching, burning, tingling, swelling and redness. Ulcers and nodules are occasionally seen. Symptoms usually resolve in 1 - 3 weeks. Again, the common sites are hands, feet and ears. |
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Last Updated on Sunday, 30 August 2009 21:57 |
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