Heat & Cold Injuries

Heat Production & Dissipation Basal Metabolic Rate BMR is increased by shivering Heat Loss: Conduction Convection Evaporation Respiration

Risk factors in heat illness Fitness and body mass index Age Gender Medical conditions Medications

Heat Related Disorders Minor heat related disorders Heat rash Heat edema Heat tetany Muscle (Heat) cramps Heat syncope Major heat related disorders Exertion associated collapse Heat Exhaustion Heat stroke

Heat Rash Known as prickly heat and miliaria rubra. It is a red, pruritic, papular rash normally seen on the skin an area of restrictive clothing and heaving sweating. It caused by inflammation of sweet glands that blocks the sweet duct Management: by cooling and drying the affected area and by preventing further conditions that cause sweet in these areas.

Heat Edema It is a mild, dependent edema in the hands, feet, and ankles seen in early stages of heat acclimatization. Edema does not indicate excessive fluid intake or cardiac, renal or hepatic disease. It is self limiting Management: loosening clothes and elevating the legs, diuretics are not indicated.

Heat Tetany It is rare and self limiting condition that occur in patients acutely exposed to short intense, heat conditions. The principal cause is hyperventilation. S & S: respiratory alkalosis, paresthesia, carpopedal spasm and tetany. Management: removal from source of heat, and controlling hyperventilation.

Muscle (Heat) Cramps They are short term, painful muscle contractions frequently seen in the calf muscle an the voluntary muscles of abdomen and extremities. They occur during exercise. Management: rest in cool environment, stretching the affected muscle, and consuming oral fluids.

Heat Syncope It occurs with prolonged standing in warm environments and is caused by low blood pressure. Heat causes vasodilatation and venous blood pools in the legs. Management: removal to cool environment, oral or IV rehydration.

Exertion Associated Collapse It occurs when individual collapses after strenuous exercise. S & S: nausea, lightheadedness and collapse, postural hypotension, profuse sweaty, rapid pulse and ventilations, normal or slightly elevated body temperature. Management: remove to cool environment, rest, oral or IV rehydration.

Heat Exhaustion It is the most common heat related disorder. It results from cardiac output insufficient to support the increased circulatory load. It is a diagnosis of exclusion when there is no evidence of heat stroke. S & S: decreased urine output, frontal headache, drowsiness, euphoria, nausea, lightheadedness, anxiety, fatigue and apathy. Postural hypotension, profuse sweaty, rapid pulse and ventilation. Management: remove to cool environment, supine resting position, remove restrictive heat dissipation, oral or IV rehydration and transfer.

Heat Stroke It the most emergent and life threatening from heat illness. It is abnormal form of hyperthermia resulting on a total failure of autoregulatory system. S & S: hot flushed skin, tachycardia, elevated body temperature, CNS dysfunction resulting in convulsions or coma. Management: ABC, cooling (passive or active)

Predisposing factors of hypothermia Injuries Chronic illness Shock Burns Head and spinal cord injuries Generalized infection Diabetes Unconscious patient Aged people

Cold Injuries Minor cold related injuries Major cold related disorders Contact freeze injury Frostnip Cold urticaria Chilblains (pernio) Solar keratitis ( Snow Blindness) Major cold related disorders Localized cutaneous cold injury Nonfreezing cold injury Freezing cold injury Accidental hypothermia Immersion hypothermia

Contact Freeze Injury Caused by contact of unprotected skin with cold material.

Frostnip It is a precursor to frostbite. It produces reversible signs of of skin blanching and numbness in localized tissue. Seen on areas of the face, nose and ears. It is self limiting tissue damage.

Cold Urticaria It is characterized by rapid onset of itchiness, redness, and swelling of skin after exposure to cold. It caused by released of histamine. Treatment includes avoiding cold and use of antihistamines.

Chilblains (Pernio) They are small skin lesions that are itchy and tender, red or purple bumps that occur on the extensor skin surface of the finger or any skin surface from chronic cold exposure. They occur several hours after to the cold. Symptoms will subside with elimination of cold. Management: protection from cold and appropriate gloves and clothing.

Solar Keratitis (Snow Blindness) It is caused by reflection ultraviolet rays to skin and eyes. S & S: excessive tearing, pain, redness, swollen eye lids, headache and hazy vision Management: patching affected eye, antibiotics and analgesics.

Localized Cutaneous Cold Injury They occur at peripheral sites on the body It classified into: Freezing (Frostbite) Nonfreezing (immersion)

Nonfreezing Cold Injury It is a syndrome called Trench Foot or Immersion Foot. It results from damage to peripheral tissues. S & S: edema, pale, pulseless and immobile. Management: eliminate further cooling, prevent further injury, analgesics, transport

Freezing Cold Injury It involves tissue destruction and possible loss. Most common areas are nose, ears, hands, fingers, feet, toes. Management: support, cover, analgesics, IV fluids.

Accidental Hypothermia It is a generalized hypothermia. It is divided into: Primary hypothermia Secondary hypothermia S & S: depends on the stage and core body temperature. Management:

Immersion Hypothermia It is a generalized hypothermia. S & S: depends on the stage and core body temperature. Management: ABC, prevent further heat loss, IVF, transport.

Prevention of cold weather & heat injuries Think of the acronym COLD C-Clean clothes O-Avoid Overheating L-Loose Layers of clothing D-Keep Dry Change your socks