The redness and itching typically occurs on cheeks, ears, fingers, and toes. Frostbite: the freezing and destruction of tissue, which happens below the freezing point of water
Frostnip: a superficial cooling of tissues without cellular destruction
Trench foot or immersion foot: a condition caused by repetitive exposure to water at non-freezing temperaturesThe normal human body temperature is often stated as 36.5–37.5 °C (97.7–99.5 °F). Hyperthermia and fever, are defined as a temperature of greater than 37.5–38.3 °C (99.5–100.9 °F). Signs and symptoms
Signs and symptoms vary depending on the degree of hypothermia, and may be divided by the three stages of severity. People with hypothermia may appear pale and feel cold to touch. Infants with hypothermia may feel cold when touched, with bright red skin and an unusual lack of energy.Cold stress refers to a near-normal body temperature with low skin temperature, signs include shivering. Cold stress is caused by cold exposure and it can lead to hypothermia and frostbite if not treated. Individuals with hypothermia often have impaired judgement, impaired sense of time and place, unusual aggression and numbness. A person with hypothermia can be euphoric and hallucinating. Mild
Symptoms of mild hypothermia may be vague, with sympathetic nervous system excitation (shivering, high blood pressure, fast heart rate, fast respiratory rate, and contraction of blood vessels). These are all physiological responses to preserve heat. Increased urine production due to cold, mental confusion, and liver dysfunction may also be present.
Once a temperature of 30 °C (86 °F) has been reached, normal ACLS protocols should be followed. Prognosis
It is usually recommended not to declare a person dead until their body is warmed to a near normal body temperature of greater than 32 °C (90 °F), since extreme hypothermia can suppress heart and brain function. Exceptions include if there are obvious fatal injuries or the chest is frozen so that it cannot be compressed. If a person was buried in an avalanche for more than 35 minutes and is found with a mouth packed full of snow without a pulse, stopping early may also be reasonable. This is also the case if a persons blood potassium is greater than 12 mmol/L.Those who are stiff with pupils that do not move may survive if treated aggressively. Survival with good function also occasionally occurs even after the need for hours of CPR. Children who have near-drowning accidents in water near 0 °C (32 °F) can occasionally be revived, even over an hour after losing consciousness. The cold water lowers the metabolism, allowing the brain to withstand a much longer period of hypoxia. While survival is possible, mortality from severe or profound hypothermia remains high despite optimal treatment. Studies estimate mortality at between 38% and 75%.In those who have hypothermia due to another underlying health problem, when death occurs it is frequently from that underlying health problem.