What are the signs and symptoms to look out for in a patient with a history of heat stroke?

Signs and Symptoms of History of Heat Stroke

Patients with a history of heat stroke require careful monitoring for persistent neurological dysfunction and other organ damage, as these may indicate long-term sequelae that can affect morbidity and mortality. 1

Neurological Signs and Symptoms

• Central nervous system abnormalities: Delirium, confusion, seizures, or coma are hallmark signs of previous heat stroke 1, 2
• Persistent neurological deficits:
  • Frontal subcortical dysfunction (unusual but reported) 3
  • Cerebellar dysfunction (more common) manifesting as uncoordinated movements 3
  • Varying degrees of irreversible brain injury (occurs in approximately 20% of patients) 2
• Cognitive impairments: Memory issues, difficulty concentrating, or altered mental status 1, 4

Cardiovascular Signs and Symptoms

• Circulatory alterations: Distributive shock characterized by vasodilatation and relative or absolute hypovolemia 1
• Hypotension: Associated with higher mortality rates (33% compared to 10% in patients without hypotension) 1
• Hypodynamic state: Observed in approximately 20% of patients 1
• Tachycardia: Rapid heart rate that doesn't normalize with rest 4

Multi-Organ Dysfunction Signs

• Liver dysfunction: Monitor for signs of acute liver failure, which can be a late complication even after initial recovery 5
• Renal impairment: Signs of acute renal failure 2
• Coagulopathy: Evidence of disseminated intravascular coagulation 2
• Respiratory distress: Symptoms of acute respiratory distress syndrome 2
• Metabolic abnormalities: Acid-base disorders and electrolyte disturbances 2

Heat Intolerance and Recurrence Risk

• Increased susceptibility to subsequent heat illness: Patients with history of heat stroke are at higher risk for recurrence 4
• Heat intolerance: Difficulty adapting to hot environments even after recovery 1
• Reduced heat tolerance during physical activity: Especially in those with history of exertional heat stroke 4

Comparison of Heat Stroke vs. Heat Exhaustion

Feature	Heat Stroke	Heat Exhaustion
Mental Status	Altered (confusion, delirium, seizures, coma)	Normal
Core Temperature	≥40°C (≥104°F)	Up to 40°C (104°F)
CNS Involvement	Yes	No
Severity	Severe, life-threatening	Moderate
Organ Dysfunction	Potential multi-organ failure	No
Mortality Risk	High if not rapidly treated	Low with proper treatment

4

Clinical Pearls and Pitfalls

• Time-sensitive assessment: The prognosis is poorest when initial treatment was delayed >2 hours from onset 2
• Medication history: Certain medications (including over-the-counter drugs and cognitive enhancers) may contribute to heat intolerance and should be assessed 5
• Pre-existing conditions: Cardiovascular disease, obesity, and other chronic conditions increase risk of complications 6
• Long-term monitoring: While psychological sequelae are rare beyond 6 months 7, neurological and organ dysfunction may persist and require ongoing assessment 3

Risk Factors for Complications

• Age extremes (very young or elderly)
• Pre-existing cardiovascular disease
• Obesity
• Chronic diseases
• Medication use (particularly those affecting thermoregulation)
• Multiple sclerosis
• Previous episodes of heat stroke

4, 6

Careful monitoring of these signs and symptoms is crucial for early identification of complications in patients with a history of heat stroke, as prompt intervention can significantly improve outcomes and prevent recurrence.