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Image: “Touch the Sky” by Elescir. License: CC BY 2.0


Heat Emergency

Prolonged exposure to heat often necessitates immediate medical attention. Heat can lead to circulatory problems, heat cramps, heat exhaustion, sunstroke, or heatstroke. In the presence of high temperatures, the body is incapable of giving off heat as much as it receives, resulting in overheating. Increased sweating causes a loss of body fluid and electrolytes, and physical exercise worsens the situation.

Heat syncope/heat exhaustion

If an individual stands for prolonged periods in a hot environmentorthostatic dysregulation with brief unconsciousness (heat syncope) or blackouts (heat exhaustion) can result. This is caused by vasodilation due to heat; blood flows to the periphery, resulting in a temporary reduction of blood supply to the brain. Shock symptoms are noted clinically (tachycardia, hypotension, and cold sweat), but the skin temperature is not elevated. Other symptoms of shock include headache, irritability, and extreme thirst. Treatment of heat syncope/heat exhaustion occurs through the (intravenous) administration of fluid, shock positioning, and cooling. In particular, older patients should be hospitalized to identify/rule out other conditions.

Heat exhaustion

Heat exhaustion caused by prolonged and marked sweating is also a mild form of heat emergency. Too little fluid can cause dehydration, with headaches, physical exhaustion, and drowsiness. A disturbed electrolyte balance (loss of sodium) promotes muscle cramps. Therapy is offered alongside any interventions in case of heat syncope. However, hospitalization is usually not necessary.

Heatstroke and sunstroke

Heatstroke and sunstroke are severe heat emergencies. Heatstroke occurs if heat gain exceeds heat loss in the body. There are 2 types of heatstroke:

  • Exertional heatstroke occurs in young individuals that engage in physical exercises in a hot environment.
  • Non-exertional heatstroke occurs in young children, chronically ill persons, and elderly people.

Heatstroke causes hyperthermia with dry, warm skin, drowsiness, nausea and vomiting, tachycardia, hypotension, cerebral seizures, and organ failure. Heatstroke must always be treated in the hospital since it can be lethal. In addition to cooling, shock positioning, and fluid replacement, intubation and anticonvulsive therapy might be necessary.

Sunstroke can also be dangerous. It results from intense sun exposureApart from symptoms of meningeal irritation, cerebral edema could also occur. Sunstroke and heatstroke share similar symptoms such as hyperthermia, drowsiness, vomiting, and symptoms of meningeal irritation, including cerebral seizures. If severe symptoms are present, hospitalization and further treatment are indicated along with the above-mentioned interventions.

Burns

Burns are tissue injuries caused by exposure to temperatures exceeding 45°C (113°F). Fire, hot liquids (scalds), lightning, or electric shocks could lead to burns.

In burns, the blood vessel barrier (endothelial cells and endothelial surface layer) is destroyed and fluid moves into the interstitial space. This leads to hypovolemia and could result in hypovolemic shock. Further, the intravascular activation of blood coagulation (disseminated intravascular coagulation) could occur and may cause multiple organ failure due to organ injury. Inhalation injury and smoke intoxication could also result depending on the cause of the burn.

Characterizing burns

Generally, burns can be differentiated by their extent and degree. The degree of a burn describes the depth of burn wounds (see table).

Degree of burn Characteristics Symptoms Healing
1st degree limited to the epidermis, no destruction of skin, hyperemia, edema from itching to pain unscarred spontaneous recovery
2nd degree, superficial burns

2nd degree, deep burns

a: superficial, limited to the epidermis, hyperemia, blistering, wet wound bed, intact sensibility
b: deep, epidermis and dermis are damaged, blistering, dry wound bed, bright and reddened areas
severe pain a: usually unscarred spontaneous recovery
b: partial recovery with scar formation
3rd degree damage of all skin layers including the superficial fascia, greyish-white discoloration of the skin painless since the nerve endings are destroyed skin regeneration no longer possible
4th degree involve the muscles, tendons, or bones, charring of tissue  painless skin regeneration no longer possible

The extent of a burn is described by the area of the affected body surface, which can be estimated using certain rules. The size of the palm of an adult is equal to 1% of the body surface area (BSA). The Wallace rule of nines is used to divide the body surface area into regions, each equaling 9% of the total BSA:

  • Head and neck equal 9%
  • One arm 9% (front side = 4.5%, backside = 4.5%)
  • One leg 18% (front side = 9%, backside = 9%)
  • The trunk is divided into 4 regions of 9%
  • Anterior thorax = 9%
  • Posterior thorax = 9%
  • Anterior abdomen = 9%
  • Lumbar region = 9%
  • The genital region equals 1% of the BSA.

For children, this classification is different because of the differences in their body proportion.

The combination of the extent of burn and degree of burn allows us to determine the severity of the burn. A burn is severe if:

  • The head, hands, or feet and genital region are affected
  • 25% of the BSA shows 2nd-degree burns (20% for children)
  • 10% of the BSA shows 3rd-degree burns

Severe burns should always be treated in a burn unit.

Therapy for burns

In addition to maintaining self-protection, first-line measures include:

  • Stabilization of the patient by securing the airway (if necessary through intubation), ventilation with 100% oxygen, fluid replacement as per the Parkland formula
  • Adequate analgesia, prophylactic antibiotics, and antitetanus toxin administration
  • Removal of clothing and sterile covering of the wound
  • Further treatments can be carried out in a burn unit or a normal hospital depending on the severity of the burn

General management of burns involves:

  • Resuscitation in the first 48 hrs
  • Prevention of complications from 48 hrs to 6 months
  • Reconstructive surgery, rehabilitation, and training in the period after 6 months

Electric Shock

In the case of electrical accidents, a mix of symptoms of thermal (local burns) and electrical injuries (cardiac arrhythmia) can be seen. The severity of the injury depends on the voltage (low voltage < 1000 V, domestic electricity; high voltage > 1000 V, lightning), current strength, duration of exposure, contact area, and other general factors such as moisture and conductivity of the skin. Possible consequences are:

  • Burns
  • Cardiac arrhythmia (ventricular fibrillation) and cardiac arrest
  • Muscle injuries leading to muscle contractions
  • CNS injuries with disturbances of consciousness

Additionally, secondary injuries due to falls (e.g., fractures, internal injuries) often occur, including injuries to the skin caused by the entry and exit of current (current brands). In the case of lightning strikes, a lightning figure in the form of a fern-like branching can often be seen on the skin.

Therapy

Self-protection is crucial when treating patients in case of electric accidents. Before the patient can be rescued from the danger zone, the power supply has to be shut off. For high-voltage accidents, this has to be done by qualified personnel. The management for electrical injuries is similar to that for burns. Additionally, possible cardiac arrhythmias have to be treated (CPR), and other potential injuries (e.g., fractures) have to be managed (bone setting, splinting, etc).

In electrical burns, 100 mL/hr of urine should be the target for flushing the kidney. Alkalization of the urine by adding sodium bicarbonate to the IV fluid increases the solubility and clearance rate of myoglobin (due to muscle breakdown) in the urine. Hemoglobinuria suggests the presence of myoglobin and indicates the need for increased fluids and mannitol.

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