Wintertime is a time of joy for many people. Holidays, snow-sports, and cozy nights by a fireplace are staples for many people when cold weather rolls around. However, cold weather can also bring respiratory viruses, slick road conditions, and cold weather injuries. Some of the most common and concerning cold weather health conditions include hypothermia, frostbite, and trench foot.
Hypothermia
Hypothermia is an involuntary drop in body temperature below 35 degrees C. It can range from mild to severe depending on body temperature, shivering, and mental status. The risk of developing hypothermia is higher in infants, the elderly, and people with conditions such as hypothyroidism, diabetes, and heart disease.
Related CE course for nurses: Environmental Emergencies: Cold-Weather Related Health Conditions
Mild
Mild hypothermia is when the body temperature falls between 32 and 35°C (90-95°F). These patients usually shiver and become pale due to vasoconstriction. Patients could experience cognitive decline, such as poor judgment, clumsiness, and drowsiness.
Treatment for mild hypothermia includes using warm blankets, removing wet clothing, and offering high-energy food and warm liquids. Long-term complications are rare when mild hypothermia is treated quickly.
Moderate
Moderate hypothermia happens when body temperatures fall between 28 and 32°C (82-90°F). These patients typically stop shivering and become lethargic and confused. Pupils may become dilated and less responsive to light. In addition, patients with moderate hypothermia are at a high risk of cardiac dysrhythmias such as atrial fibrillation.
Patients with moderate hypothermia need slow, gentle rewarming. Often, these patients will receive warm IV fluids in addition to being wrapped in warm blankets. They may need supplemental oxygen and close monitoring of cardiac rhythms.
Severe
Severe hypothermia is present with a core body temperature of less than 28°C (82°F). Patients with severe hypothermia are at a high risk of cardiopulmonary collapse and death. They often have severe electrolyte imbalances and impaired level of consciousness.
Severe hypothermia almost always requires ICU level treatment and care. Patient rewarming techniques can include warmed IV fluids, warmed gastric irrigation through an NG tube, warmed fluids through a 3-way Foley catheter, and even ECMO or CBP.
Treating hypothermia
Patients being rewarmed need close monitoring of potassium, glucose, and other electrolytes. In addition, these patients are at a high risk of severe cardiac dysrhythmias and hypotension. Mortality rates for severe hypothermia have been reported as high as 50% in some intensive care settings.
Frostbite
Frostbite is another cold weather health condition that can range from mild to severe and is more often found in young, elderly, and chronically ill patients. This condition is most often found on the fingers, toes, ears, and nose. It is typically caused by skin exposure to temperatures of 0°C and below. Recent studies show that nearly 20% of frostbite injuries require some type of surgical intervention, such as debridement or amputation.
Frostbite is caused by vasoconstriction and poor blood flow to the affected area. Re-establishing blood flow and temperature regulation are essential to prevent tissue death. Frostbite injuries are classified in the same way that burn injuries are classified:
- 1st degree: Also referred to as “frostnip,” causes redness, numbness or tingling, and some swelling in the affected area. Reversible with gentle heat.
- 2nd degree: Still superficial, contained to the first layer of skin. Blisters may appear after rewarming.
- 3rd degree: Injury to deeper layers of skin, often causing blood-filled blisters and eschar. These injuries often require surgical debridement and possible amputation.
- 4th degree: The most severe form of frostbite. 4th degree frostbite extends through the skin and muscle, reaching the tendon and bone. This results in significant tissue death and amputation of the affected area.
Treatment of frostbite
Treatment of frostbite depends on the degree of injury and the area of involvement. In mild cases, the affected area should be submerged in warm water until it becomes red. Because frostbite can cause numbness, patients may need to submerge healthy tissue in the hot water to assess temperature and avoid burns. Skin should only be rewarmed when there is no chance of refreezing, as this can make the injury even worse.
Deeper injuries should be rewarmed carefully under the supervision of a medical provider. In some cases, thrombolytics such as TPA can be administered to break up blood clots in the affected area to restore adequate perfusion.
The most severe injuries may require amputation, and providers are careful to take the minimal amount of tissue. Skin grafting can be used for cases involving large areas or over the face.
Trench foot
Trench foot, while less common than it was centuries ago, is still a problem that can appear in anyone who spends extended periods of time in cold, wet, and unsanitary conditions. Campers, construction workers, military personnel, hunters, and homeless populations are at the highest risk of developing trench foot.
While trench foot is not a freezing injury, it has a similar mechanism of injury to frostbite. When feet are exposed to cool, wet conditions for long periods of time, blood vessels constrict and perfusion to the area decreases. In addition, moisture makes the skin of the feet more fragile, increasing susceptibility to infections.
The first signs and symptoms of trench foot include numbness, tingling, skin discoloration, and swelling. If left untreated, tissue death, necrosis, and even gangrene can develop.
Management of trench foot includes letting feet get completely dry, keeping them warm, and applying antibiotic ointment to any open sores. Serious cases may require wound debridement, IV antibiotics, and even amputation. People working or living in high-risk areas should change their socks frequently and remove their shoes and socks while resting to allow the feet to dry.
Preventing cold weather health conditions
Most cold weather health conditions can be avoided by avoiding long exposures to cold, using the correct gear for the weather, and having a safety plan in case of cold weather emergencies. Anyone hoping to enjoy outdoor recreation in the colder months should ensure that they have the proper gear, have checked the weather forecast, and have notified an emergency contact about their plans.
People should seek shelter at the first sign of any cold weather injury, since longer exposure is associated with poorer outcomes.
