Heat Exhaustion: A Comprehensive Guide for Junior Doctors

Welcome to the fast-paced world of emergency medicine! Heat exhaustion is a common yet critical condition we encounter during the hotter months. Understanding its management can make a significant difference in patient outcomes. Let's dive into a structured approach to heat exhaustion, based on the latest guidelines and best practices.

History Taking: Key Questions

When assessing a patient suspected of heat exhaustion, your history should focus on the following:

Exposure History:

• Duration and Intensity of Heat Exposure: How long has the patient been exposed to high temperatures? Was the exposure intense (e.g., vigorous exercise, outdoor work)?

• Environment: Were they in a hot, humid environment or exposed to direct sunlight?

Symptom Onset and Duration:

• When did symptoms start?

• How have symptoms progressed?

Symptoms:

• General Symptoms: Have they experienced excessive sweating, weakness, dizziness, headache, nausea, or vomiting?

• Severity of Symptoms: Are they feeling faint, have muscle cramps, or are experiencing altered mental status?

Medical History:

• Do they have any pre-existing conditions such as cardiovascular disease or diabetes?

• Are they on any medications that might affect thermoregulation (e.g., diuretics)?

Hydration Status:

• How much fluid have they consumed recently? Have they been drinking enough water?

Physical Examination: What to Look For

When examining a patient with suspected heat exhaustion, focus on:

General Appearance:

• Skin: Look for signs of excessive sweating and a pale, cool, or clammy appearance. Skin that is hot and dry might suggest heat stroke rather than heat exhaustion.

• Vital Signs: Measure temperature (elevated but usually below 40°C for heat exhaustion), pulse (often tachycardia), and blood pressure (often low).

Neurological Status:

• Assess for confusion, irritability, or lethargy. Heat exhaustion typically presents with mild confusion, but severe alterations in consciousness suggest heat stroke.

Cardiovascular Examination:

• Check for tachycardia and hypotension. Heat exhaustion often results in elevated heart rate and reduced blood pressure.

Musculoskeletal Examination:

• Evaluate for muscle cramps or weakness, which are common in heat exhaustion.

Investigations: What to Order

In most cases, a thorough history and physical examination will guide your management, but certain investigations can help confirm the diagnosis and assess severity:

Blood Tests:

• Electrolytes: Look for electrolyte imbalances, such as low sodium or potassium, which can occur due to excessive sweating.

• Renal Function Tests: Assess kidney function, as dehydration can impact renal performance.

• Urinalysis: Check for signs of dehydration and possible electrolyte imbalances.

• ECG: Consider an ECG if the patient has significant cardiovascular symptoms or if there is concern about underlying heart conditions.

Management Plan: What to Do

The management of heat exhaustion primarily focuses on cooling the patient and rehydration. Follow these steps:

Immediate Cooling:

• Move the patient to a cooler environment, preferably air-conditioned.

• Remove excess clothing and apply cool, wet cloths to the skin or use fans to facilitate evaporation.

• Consider immersion in cool water if available and safe.

Hydration:

• Encourage oral rehydration with fluids containing electrolytes (e.g., sports drinks, oral rehydration solutions).

• In severe cases or if the patient cannot drink, administer intravenous fluids (e.g., isotonic saline).

Monitoring:

• Continuously monitor vital signs and mental status.

• Be prepared to transition to more intensive care if symptoms do not improve or if there is evidence of progression to heat stroke.

Prevention Education:

• Educate the patient on preventing future episodes, such as staying hydrated, avoiding excessive heat exposure, and recognizing early symptoms of heat-related illnesses.