What Is Heat Stroke?

Heatstroke is caused by central nervous system and / or cardiovascular dysfunction due to central dysfunction of body temperature regulation, sweat gland failure and excessive water and electrolyte loss in hot summer season, high temperature and / or high humidity Acute disease. According to clinical manifestations, heat stroke can be divided into threatened heat stroke, mild heat stroke, and severe heat stroke. Among them, severe heat stroke is divided into heat cramps, heat failure and heat radiation. Heat shot is the most severe type of heat stroke.

Basic Information

English name: heat stroke
English alias: sunstroke
Visiting department: Emergency Department

Multiple groups: Workers working in high temperature environments, elderly and infants
Common causes: Increased body heat production, reduced heat dissipation, and reduced thermal adaptability
Common symptoms: High fever, sweat or no sweat, thirst, nausea, vomiting, convulsions, etc.

Causes of heat stroke

Increased heat production

Work in hot and hot seasons or in high-temperature, high-humidity and poorly ventilated environments, and insufficient measures to prevent heatstroke and cooling.

2. Reduced body heat dissipation

High ambient temperature and humidity, poor ventilation, dysfunction of sweat glands, etc.

3. The body's thermal adaptability declines

Elderly and frail women during puerperium and patients with basic diseases such as cardiovascular and cerebrovascular diseases are relatively weak in heat adaptability and are more susceptible to disease in the same environment.

Clinical manifestations of heat stroke

According to China's "Diagnostic Criteria for Occupational Heat Stroke" (GB11508-89), heat stroke is divided into threatened heat stroke, mild heat stroke, and severe heat stroke.

Threatened heat stroke

In a high temperature environment, headache, dizziness, thirst, sweating, weakness in the extremities, lack of concentration, uncoordinated movements, etc., and the body temperature is normal or slightly elevated.

2. Mild heat stroke

In addition to the above symptoms, body temperature is often above 38 ° C, accompanied by flushing, heavy sweating, hot skin, or wet and cold limbs, pale, decreased blood pressure, and increased pulse.

3. Severe heat stroke

Includes heat cramps, heat exhaustion, and heat radiation sickness.

Thermal cramps are painful muscle spasms that occur suddenly during or after an activity, and usually occur in the muscle groups on the back of the lower limbs (gastrocnemius and Achilles tendon), and can also occur in the abdomen. Muscle spasms may be related to severe body sodium loss (sweating and drinking hypotonic fluids) and hyperventilation. Heat cramps can also be an early manifestation of heat shot disease.

Heat exhaustion is caused by excessive loss of body fluids and salts due to excessive sweating. It often occurs in people who work or exercise in hot environments without replenishing enough water. It also occurs in people who are not adapted to high temperature and humidity. The symptoms are: Sweating, extreme thirst, fatigue, headache, nausea and vomiting, high body temperature, may have obvious signs of dehydration such as tachycardia, orthostatic hypotension or syncope, without obvious manifestations of central nervous system damage. Heat failure can be an intermediary process of heat cramps and heat shots. If not treated in time, it can develop into heat shots.

Heat shot disease is a fatal emergency. According to the state and pathogenesis of the patient at the time of onset, it is clinically divided into two types: labor-type and non-laboratory heat-ray disease. The laborers are mainly endogenous excessive heat production in high temperature environments, which are more common in healthy young people, and often occur during heavy physical labor, sports (such as long-distance runners in hot weather) or military training. High fever, convulsions, coma, sweating or no sweating, fast heart rate, it can happen quickly. Its non-labor is mainly due to the reduction of heat dissipation caused by temperature regulation dysfunction in high temperature environments (such as the elderly without air conditioning in the living environment during the heat wave attack), which can occur within a few days. The signs are: high fever (rectal temperature 41 ° C), dry skin (wet early), blurred consciousness, convulsions, and even no response, peripheral circulation failure or shock. In addition, laborers are more susceptible to rhabdomyolysis, acute renal failure, liver failure, DIC or multiple organ failure, and have a higher mortality rate.

Heatstroke check

1. Blood and urine routines: total white blood cells and neutrophils, proteinuria and cast urine.

2. Liver, kidney function and electrolyte testing: In severe cases, transaminase elevation, serum creatinine and urea nitrogen elevation, creatine kinase (CK) and lactate dehydrogenase (LDH) elevation, electrolyte disorders, and abnormal coagulation mechanisms often occur.

3. Electrocardiogram: mostly manifested as tachyarrhythmia. It is usually sinus tachycardia, ventricular premature beats, and sometimes bradycardia, which can be accompanied by T wave and ST segment abnormalities.

4.CT examination: Convenient, rapid and safe, especially for emergency patients to make a quick diagnosis, which plays an important role in fighting for time to rescue patients.

5. Blood gas analysis: often suggest metabolic acidosis and respiratory alkalosis, hyperlactic acidemia, hypoxemia, etc.

Heatstroke diagnosis

The onset season, high temperature and / or high humidity environment, and clinical manifestations (high fever, coma, convulsions) are the key to the diagnosis of heat stroke. Attention should also be paid to excluding other organic diseases.

Heat stroke treatment

1. Treatment of Threat Stroke and Mild Stroke

Immediately transfer the patient to a cool, ventilated place or under an electric fan, preferably to an air-conditioned room to increase radiation heat dissipation, give a cool salty drink, and give a cold compress to those with high body temperature.

2. Treatment of severe heat stroke

(1) Cooling treatment

Rapid cooling is the primary measure of treatment.

1) In vitro cooling: Quickly get out of the high temperature and high humidity environment, transfer to a cool and ventilated place, lie on the patient and remove the whole body clothing, massage the skin and muscles, and promote heat dissipation. For those without circulation disorder, rub the bath with ice water or infiltrate the body to cool the water at 27 ~ 30 . For those with circulation disorders, use evaporative cooling to cool down, wipe the skin repeatedly with cold water, and use an electric fan or air conditioner to accelerate evaporation.

2) In vivo cooling: in vitro cooling is not effective, gastric or rectal lavage with iced saline, peritoneal lavage or hemodialysis with sterile normal saline, or autologous blood cooled in vitro and returned to the body to cool.

3) Drug cooling: In patients with chills, chlorpromazine can be administered by intravenous infusion. And monitor blood pressure at the same time.

(2) symptomatic treatment

1) Patients with coma should keep the airway open, give oxygen, and intubate if necessary.

2) Actively correct water and electrolyte disorders and maintain acid-base balance.

3) The rehydration rate should not be too fast, so as to avoid triggering heart failure, and the rapid effect of digitalis preparations in case of heart failure,

4) Apply booster drugs to correct shock.

5) Patients with suspected cerebral edema should be dehydrated with mannitol.

6) Hemodialysis can be performed in patients with acute renal failure.

7) Use heparin as appropriate when disseminated intravascular coagulation occurs, and add antifibrinolytic drugs when necessary.

8) Adrenal corticosteroids have certain effects on the body's stress and tissue response caused by high temperature and the prevention and treatment of cerebral edema and pulmonary edema, but the dosage should not be too large, and the medication time should not be too long to avoid secondary infection.

9) Actively prevent infection.

(3) Monitoring

1) Body temperature monitoring: continuous monitoring of body temperature changes during cooling.

2) Monitor urine volume: keep urine volume> 30 ml / hour.

3) Monitoring of coagulation function: closely monitor prothrombin time, partial thromboplastin time, platelet count and fibrinogen.