Heat Exhaustion and Heatstroke (Heat Prostration, Sunstroke)
Heat exhaustion and heatstroke are medical emergencies brought on by exposure to more heat and humidity than the body can adapt to. Although the two terms are sometimes used interchangeably, they are distinctly different conditions.
Heat exhaustion is caused by dehydration, usually the result of sweating heavily and not consuming adequate replacement fluids. Warning signs include increasing fatigue, weakness, and feelings of anxiety, along with a drenching sweat. As the condition worsens, blood pressure drops, the pulse slows, and the skin becomes pale and clammy. The person could be confused and might faint.
Heatstroke develops when the body's ability to cool itself by sweating fails during very hot, humid weather. It is potentially more serious than heat exhaustion because it can quickly lead to a fever of 104°F (40°C) or higher. Unlike heat exhaustion, heatstroke comes on suddenly, but is sometimes preceded by a headache, dizziness, and fatigue. The person's skin will be hot, flushed, and dry. The pulse may rise as high as 160 to 180 beats per minute, and breathing may be rapid and shallow. Confusion and disorientation may occur, followed soon by unconsciousness or convulsions and a collapse of the circulatory system.
The most common victims of heatstroke are the elderly, the obese, and people who consume too much alcohol or who are weakened by chronic illness. Certain drugs, such as the pheno-thiazines used to treat mental illness or the diuretics used to reduce body fluids, also increase the risk.
Diagnostic Studies and Procedures
Heat exhaustion and heatstroke are both diagnosed by the symptoms. Once the immediate emergency has been brought under control, a doctor will order blood and urine tests and take a complete medical history to determine whether drug toxicity could have contributed to the episode.
Medical Treatments
Most cases of heat exhaustion do not need treatment beyond first aid measures. But if the episode is severe or the person does not respond to first aid, a doctor should be seen immediately, preferably in the nearest hospital emergency room. It may be necessary to administer intravenous fluids or give medication to stimulate the heart.
Heatstroke requires immediate hospitalization so that the patient's temperature can be continuously monitored and controlled. If convulsions continue, an intravenous sedative, usually diazepam (Valium) or a barbiturate, will be given. Bed rest is necessary for several days after an episode of heatstroke, and temperature may be erratic for weeks.
Alternative Therapies
Hydrotherapy. If it is necessary to perform physical labor in hot weather, use cool water to keep your temperature from rising to dangerous levels. A cool shower or a swim in a pool, pond, lake, or other body of readily accessible water will do. Alternatively, soak a towel in a bucket of cool water and apply it as a compress.
Self-Treatment
Common sense prevention is the best approach. Keeping the body well hydrated helps avoid heat exhaustion. Drink water, fruit juice, broth, or other non-alcoholic beverages every hour or so, even if you do not feel thirsty. Beverages that contain caffeine are not recommended because of their diuretic and stimulatory effects.
Avoid strenuous outdoor activities in hot and humid weather, particularly between 10:00 a.m. and 4:00 p.m. If your job demands that you work under these conditions, wear light-weight, light-colored clothing, try to stay out of the sun, drink plenty of liquids, and eat light meals. Rest frequently in a cool, shady place. If you have a chronic cardiovascular, neurological, or skin disease, seek your doctors advice about working outdoors in the heat.
Other Causes of Symptoms
An insulin overdose, poisoning, hemorrhage, or traumatic shock can produce symptoms similar to those of heat exhaustion. Food, chemical, or drug poisoning may mimic heatstroke.