Heat Exhaustion

A clinical illness known as heat exhaustion is defined by volume depletion in patients who have been subjected to heat stress. The majority of heat exhaustion instances in people who are in hot environments are caused by combined salt and water depletion following insufficient fluid and salt supplementation.

CLINICAL FEATURES: There are many different heat exhaustion indications and symptoms.

1. Symptoms: Early complaints of fatigue and vague malaise may progress to weakness, vertigo, nausea and vomiting, and headache.

2. Physical examination findings: With significant dehydration, signs may include muscle cramps, orthostatic syncope, tachycardia, hyperventilation, and hypotension. Body temperature is normal or slightly elevated. Sweating may be profuse. Mental function is unaffected, and there are no indications of significant CNS injury.

DIFFERENTIAL DIAGNOSES 

It includes cerebrovascular accident, drug ingestion, exacerbation of preexisting medical illness, psychological factors, infection, viral syndromes, and heat stroke.

EVALUATION

1. A history and physical examination should lead to an accurate diagnosis.

2. Laboratory studies: There is no need for laboratory tests in mild cases. A CBC, a serum electrolyte panel, and a liver function panel may be useful in diagnosing hypernatremia, hyponatremia, hemoconcentration, or hepatic injury in moderate- to severe-case situations. The degree of dehydration can be assessed using urine-specific gravity readings and blood urea nitrogen/creatinine ratios.

THERAPY: The patient should receive aggressive treatment for potential heat stroke if there is any doubt regarding the severity of the heat illness.

1. Cool environment: The patient with an elevated body temperature should be cooled using a room-temperature water mist spray and fan to aid in evaporation. Cool packs are placed on the neck, axilla, and groin speed cooling.

2. Correction of volume and electrolyte imbalances: Usually, symptoms resolve rapidly with intravenous and oral hydration.

— The patient's condition should dictate the kind and amount of fluid.

— To avoid cerebral edema, the free water deficit in the hypernatremic patient should be gradually restored over 48 hours. Severely hyponatremic patients should also be treated carefully and rectified gradually.

DISPOSITION

1. Discharge: In young, healthy patients who respond rapidly to treatment, no additional testing is required; these patients may be discharged with education about preventive techniques.

2. Admission: Older patients, particularly those with cardiovascular disease or serious illness, require more careful fluid and electrolyte replacement and may need admission. Extremely young patients may also need extended intravenous fluid therapy.