Heat Illnesses and Heat Stroke - Differential Diagnosis Framework Heat Cramps: • Muscle pain or spasm - legs, arms or abdomen • Due to: - Strenuous exercise in the heat - Dehydration - Loss of sodium/Potassium - Extreme environmental conditions - Neurogenic fatigue Heat Rash: • Small red bumps/blisters on the skin • Areas that stay wet from sweat Heat Injury: • Exertional heat illness → Hypernatremia & end organ damage without neuro manifestations • Organ involvement: Muscles, Kidneys, Liver • Labs: - Metabolic acidosis - Rhabdomyolysis - AKI - Liver failure Heat Syncope / Exercise Associated Collapse: • Pathophysiology: Volume depletion → Decreased vasomotor tone → Postural hypotension → Syncope • Signs/Symptoms: - Lightheadedness - Tunnel vision - Pale and sweaty skin - Decreased pulse rate - Core temp normal/mildly elevated Heat Exhaustion: • Inability to maintain adequate cardiac output due to strenuous physical exercise and environmental heat stress • Criteria: - Athlete - difficulty continuing with exercise - Core body temp 101-104 degrees F - No significant CNS dysfunction • Other manifestations: - Tachycardia & hypotension - Extreme weakness - Dehydration and electrolyte losses - Ataxia and coordination problems - syncope/lightheadedness - Profuse sweating, pallor, “prickly heat” sensations - Headache - Abdominal cramps, N/V, diarrhea - Persistent muscle cramps Exertional Heat Stroke: EMERGENCY • Multi-system illness: 1. CNS dysfunction (encephalopathy) 2. Organ and tissue damage (AKI, Liver injury, Rhabdomyolysis, Thermal cardiomyopathy, ARDS, DIC) 3. High body temperatures • Criteria: - Core temp > 104 F - CNS dysfunction: • Disorientation, Headache, Irrational behavior, Irritability, Emotional instability, Confusion, Altered consciousness, Coma/seizure • Other Findings: - Tachycardia, Hyperventilation, Dizziness, Nausea, Vomiting, Diarrhea, Weakness, Profuse sweating, Dehydration, Dry mouth, Thirst, Muscle cramps, Loss of muscle function, Ataxia • Lab Findings: - Mild coagulopathy - Possible DIC - Mild lactic acidosis - CPK elevation - Hypoglycemia - Hypocalcemia - Hyperkalemia #heat #illness #differential #diagnosis #causes #stroke #heatstroke
