Cold-Related Injuries

This article is currently under review and may not be up to date. Please come back soon to see the finished work! (12/11/2020)

Original Editor - Puja Gaikwad

Top Contributors - Puja Gaikwad, Kim Jackson, Reem Ramadan, Vidya Acharya and Wanda van Niekerk  

Introduction

Cold injuries are a result of exposure to cold environments during physical activity. Many athletes participate in fitness pursuits and physical activity year-round in environments with cold, wet, or windy conditions or a combination of these, thereby putting themselves in danger of cold-related injuries. Cold exposure can be uncomfortable, can impair performance and can be life-threatening. Cold injuries and illnesses usually affect military personnel, traditional winter-sport athletes, and outdoor-sport athletes, like those involved in running, cycling, mountaineering, and swimming etc. Traditional team sports like football, baseball, softball, soccer, lacrosse, and track and field have seasons that stretch into late fall or early winter or begin in early spring when weather conditions may rise vulnerability to cold injuries.

The NATA position statement states that the occurrence of these injuries depends on Low air or water temperatures (or both) and The influence of wind on the body's ability to take care of a normothermic core temperature, due to localized exposure of the extremities to cold air or surfaces.

Alpine Environments

Cold conditions are often expected in alpine environments. Furthermore, open exposed areas, like mountain peaks, mean that windy conditions are also commonplace in these environments and may contribute significantly to cold temperatures (also referred to as the 'wind chill factor'). The collective effect of those conditions is heat loss, which places extra demands on the body. For instance, a decrease in core body temperature of just 1°C causes the muscles to shiver, which in turn can lead to low blood glucose levels (hypoglycaemia) and thereby reduced sporting performance.

Types

Cold injuries are classified into three broad categories:

1. Decreased core temperature (Hypothermia)
2. Freezing-tissue injuries of the extremities
3. Non-freezing injuries of the extremities

Hypothermia

Hypothermia is a significant drop in body temperature [below 95°F (35°C)] as the body’s heat loss exceeds its production. thereby the body is not able to maintain a normal core body temperature. This can occur quickly within a couple of hours or gradually over days and weeks. Conditions which will cause hypothermia are cold temperatures, insufficient clothing and equipment, wetness, poor nutrition, duration of the event and exposed/uncovered skin.

Wind-Chill temperature index (WCT) demonstrates how cold an individual feels when exposed to a combination of cold air and wind. This index is a very useful and necessary tool to monitor the conditions individuals are exposed to during events held in colder weather calculated through a formula but multiple graphs and apps are available for quick reference. As the WCEI indicates, wind speed interacts with ambient temperature to significantly increase body cooling. If the body and clothing are wet because of sweat, rain, snow or immersion, the cooling is even more pronounced due to evaporation of the water held close to the skin by wet clothing.

The signs and symptoms of hypothermia can vary with each individual, depending upon previous cold weather injury (CWI), race, geological origin, ambient temperature, medications, clothing, fatigue, hydration, age, activity levels and others. Hypothermia is typically classified as mild, moderate, or severe, depending upon measured core temperature. Initially, the athlete may feel cold, begin to shiver and be not able to perform motor function leading to impaired athletic and mental performance. Early recognition of these symptoms is key to preventing more severe hypothermia. If early symptoms of hypothermia are not recognized or treated, the core body temperature will continue to decrease.

Freezing Injuries of the Extremities

In conditions of prolonged cold exposure, the body sends signals to the blood vessels of hands and feet to constrict so as to preserve blood flow to vital organs. This helps the body by preventing a further drop in internal body temperature by exposing less blood to the outside cold. As this happens, toes and fingers become colder and colder eventually resulting in the injury of the involved tissues. Damage to the frostbitten tissue happens due to electrolyte concentration changes within the cells, leading to water crystallization within the tissue. For cells to freeze, the tissue temperature must be below 28°F (−2°C). The severity of frostbite is directly associated with the time of exposure and is divided into three degrees based on the depth of the injured tissue.

Frostnip

Frostnip is the stage before frostbite and occurs when the superficial skin cools below 50°F (10°C). The skin becomes cold and red, and individuals feel a tingling painful sensation. It usually occurs in the nose, ears, cheeks, fingers, and toes and does not cause long term damage.

Mild/superficial frostbite

This occurs when skin temperature drops below 28°F (-2°C) and superficial tissues freeze. Initially, skin appears reddened and then turns white or pale. Individuals can experience stinging, burning, and swelling at the site of injury. A fluid-filled blister can be seen12 to 36 hours after rewarming.

Deep/severe frostbite

It occurs when deep layers of skin are affected. Skin looks white or blueish-grey and individuals experience numbness. Large blisters can develop 24-48 hours after rewarming. Later the injured area will turn black and hard as tissue dies. Medical attention for frostbite is needed when there are signs and symptoms of superficial or deep frostbite.

In mountaineers, reported rates of hypothermia and frostbite include 3% to 5% respectively of all injuries and 20% of all injuries in Nordic skiers. Cold injury frequency in military personnel is reported to range from 0.2 to 366 per 1000 exposures.

Non-freezing injuries of the extremities

Chilblain

Chilblain a nonfreezing cold injury also referred to as pernio, is an injury associated with extended exposure (1–5 hours) to cold, wet conditions. Chilblain severity is time and temperature related. The higher the temperature of the water (generally ranging from 32°F [0°C] to 60°F [16°C]), the longer the duration of exposure required to develop chilblain. Exposure time is usually measured in hours or even days, rather than the minutes or hours associated with frostbite. It is an exaggerated or uncharacteristic inflammatory response to cold exposure. Prolonged constriction of the skin blood vessels leads to hypoxemia and vessel wall inflammation; edema in the dermis can also be present. It may occur with or without freezing of the tissue. The hands and feet are most commonly affected sites, but chilblain of the thighs has also been reported. Situations during which this will happen include alpine sports, mountaineering, hiking, endurance sports, and team sports in which footwear and clothing remain wet for prolonged periods due to water exposure or sweating.

Immersion (trench) foot

Immersion foot typically occurs with prolonged exposure (12 hours to 4 days) to a cold environment, wet conditions, usually in temperatures ranging from 32°F to 65°F (0°C–18°C). It usually affects primarily the soft tissues, including nerves and blood vessels, due to an inflammatory response leads to high levels of extracellular fluid. The foremost common mechanism for developing trench foot is the continued wearing of wet socks or footwear (or both).

Signs and symptoms

Conditions	Signs and Symptoms
Hyperthermia Mild	Core temperature 98.6°F to 95°F (37°C -35°C) Amnesia, Lethargy Vigorous shivering Impaired fine motor control Cold extremities Polyuria Typically conscious Blood temperature within normal limits
Moderate	Core temperature 94°F to 90°F (34°C -32°C) Depressed respiration and pulse Cardiac arrhythmias Cyanosis Cessation of shivering Impaired mental function Slurred speech Impaired gross motor control Loss of consciousness Muscle rigidity Dilated pupils Blood pressure decreased or difficult to measure
Severe	Core temperature below 90°F (32°C) Rigidity Bradycardia Severely depressed respiration Hypotension, pulmonary edema Spontaneous ventricular fibrillation or cardiac arrest Usually comatose
Frostbite Mild/superficial	Dry, waxy skin Erythema Edema Transient tingling or burning sensation The skin contains white or blue grey-coloured patches Affected skin feels cold and firm to touch Limited movements of the affected area
Deep	Skin is hard and cold The skin may be waxy and immobile Skin colour is white, grey, black or purple Vesicles present Burning aching, throbbing, or shooting pain Poor circulation in the affected area Progressive tissue necrosis Neurapraxia Hemorrhagic blistering develops within 36 to 72 hours Muscle, peripheral nerve, and joint damage likely
Chilblain/Pernio	Red or cyanotic lesions Swelling Increased temperature Tenderness Itching, numbness, burning or tingling Skin necrosis Skin sloughing
Immersion (trench) foot	Burning, tingling or itching Loss of sensation Cyanotic or blotchy skin Swelling Pain/ sensitivity Blisters Skin fissures or maceration

Risk Factors

• Non-environmental: Athletes are often predisposed to cold-weather injuries before going outside. Risk factors for increased susceptibility to cold-weather injuries include Nutrition and hydration, age, medications, body size and composition, fitness level, and clothing. Certain medical conditions can predispose athletes to cold injuries, including exercise-induced bronchospasm (EIB), Raynaud syndrome and cardiovascular disease.
• Environmental: Environmental conditions like cold temperatures and weather conditions may put added stress on the body. Before training or competing outside, review various environmental conditions such as air temperature, humidity, rain, snow and wind to determine if it is safe for athletes.

Management

Hypothermia (Mild)

• Identify the signs and symptoms of hypothermia, which include vigorous shivering, increased blood pressure, rectal temperature < 98.6°F (37°C) but > 95°F (35°C), fine motor skill impairment, lethargy, apathy, and mild amnesia.
• The rectal temperature obtained using a thermometer (digital or mercury) which will read below 94°F (34°C) is the preferred method for assessing core temperature in an individual suspected of being hypothermic.
• Begin by removing wet or damp clothing; insulating the athlete with warm, dry clothing or blankets (including covering the head); and moving the athlete to a warm environment with shelter from the wind and rain.
• When rewarming, apply heat only to the trunk and other areas of heat transfer, including the axilla, chest wall, and groin. Rewarming the limbs can produce after drop, which is caused by dilation of peripheral vessels in the arms and legs when warmed, this dilation sends cold blood, often with a high level of acidity and metabolic byproducts, from the periphery to the core. This blood cools the core, resulting in a drop in core temperature, and can lead to cardiac arrhythmias or even death.
• Provide warm, nonalcoholic fluids and foods containing 6% to 8% carbohydrates to help sustain shivering and maintain metabolic heat production.

Hypothermia (Moderate/Severe)

• Identify the signs and symptoms of moderate and severe hypothermia, which can include cessation of shivering, very cold skin on palpation, depressed vital signs, rectal temperature between 90°F (32°C) and 95°F (35°C) for moderate hypothermia or below 90°F (32°C) for severe hypothermia, impaired mental function, slurred speech, loss of consciousness, and gross motor skill impairment.
• If an athlete with suspected hypothermia having signs of cardiac arrhythmia, they should be moved very gently to prevent paroxysmal ventricular fibrillation.
• Begin with a primary evaluation to determine the need for cardiopulmonary resuscitation (CPR) and activation of the EMS. Remove wet or damp clothing; insulate an individual with warm, dry clothing or blankets covering the head and move them to a warm environment with shelter from the wind and rain.
• immediately initiate rewarming strategies and continue rewarming during transport and at the hospital. During the treatment and/or transport, continually examine vital signs and be prepared for airway management. When rewarming, provide heat only to the trunk and other areas of heat transfer, including the axilla, chest wall, and groin along with more aggressive rewarming procedures, including inhalation rewarming, heated intravenous fluids, peritoneal lavage, blood rewarming, and use of antiarrhythmic drugs.
• When immediate management is complete, keep a check on post-rewarming complications, including infection and renal failure.

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