A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A previously healthy 44-year-old man is brought by his coworkers to the emergency department 45 minutes after he became light-headed and collapsed while working in the boiler room of a factory. He did not lose consciousness. His coworkers report that 30 minutes prior to collapsing, he told them he was nauseous and had a headache. The patient appears sweaty and lethargic. He is not oriented to time, place, or person. The patient’s vital signs are as follows: temperature 41°C (105.8°F); heart rate 133/min; respiratory rate 22/min; and blood pressure 90/52 mm Hg. Examination shows equal and reactive pupils. Deep tendon reflexes are 2+ bilaterally. His neck is supple. A 0.9% saline infusion is administered. A urinary catheter is inserted and dark brown urine is collected. The patient’s laboratory test results are as follows:
Laboratory test
Blood
Hemoglobin 15 g/dL
Leukocyte count 18,000/mm3
Platelet count 51,000/mm3
Serum
Na+ 149 mEq/L
K+ 5.0 mEq/L
Cl- 98 mEq/L
Urea nitrogen 42 mg/dL
Glucose 88 mg/dL
Creatinine 1.8 mg/dL
Aspartate aminotransferase (AST, GOT) 210
Alanine aminotransferase (ALT, GPT) 250
Creatine kinase 86,000 U/mL
Which of the following is the most appropriate next step in patient management?
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A
Acetaminophen therapyIncorrect. Acetaminophen does not lower temperature in heat stroke (no elevated hypothalamic set-point) and can worsen hepatic and renal injury already evident in this patient.
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B
DantroleneIncorrect. Dantrolene treats malignant hyperthermia or neuroleptic malignant syndrome; there is no anesthetic or neuroleptic exposure here.
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C
Ice water immersionCorrect. Ice-water immersion provides the fastest reduction of core temperature and is the proven mortality-reducing therapy for exertional heat stroke.
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D
HemodialysisIncorrect. Hemodialysis may be required later for rhabdomyolysis-driven AKI or hyperkalemia, but is not the immediate priority while the patient remains hyperthermic.
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E
Intravenous dantrolene with rapid sodium bicarbonate infusionIncorrect. Combining dantrolene with bicarbonate addresses neither classic heat stroke nor the rhabdomyolysis acidosis correctly; aggressive external cooling is the proven mortality-reducing intervention before adjunctive measures.
↑ Tap an answer to reveal the reasoning
Answer: C. A worker collapses in a hot boiler room with core temperature 41 C, altered mental status, tachycardia, hypotension, rhabdomyolysis (CK 86,000, dark brown urine from myoglobin), acute kidney injury (Cr 1.8, BUN 42), thrombocytopenia, and transaminitis. This is classic exertional/environmental heat stroke. The single intervention that reduces mortality is rapid cooling, and ice-water immersion is the fastest method (cooling rate approximately 0.2 C/min). The goal is to drop the core temperature below 39 C as quickly as possible because every additional minute above 40 C causes ongoing multi-organ injury (cytokine storm, endothelial damage, DIC, rhabdomyolysis).
Antipyretics (acetaminophen, NSAIDs) do NOT work in heat stroke because the hypothalamic set-point is normal; the problem is failure of heat dissipation, not pyrogen-driven fever. They also worsen hepatotoxicity and AKI. Dantrolene is reserved for malignant hyperthermia (after volatile anesthetics) or neuroleptic malignant syndrome, neither of which fits this exposure. Hemodialysis may eventually be needed for refractory rhabdomyolysis-induced AKI or hyperkalemia, but it is never the next step in an acutely hyperthermic patient who needs immediate cooling.
**Why each option:**
**A.** Acetaminophen does not lower temperature in heat stroke (no elevated hypothalamic set-point) and can worsen hepatic and renal injury already evident in this patient.
**B.** Dantrolene treats malignant hyperthermia or neuroleptic malignant syndrome; there is no anesthetic or neuroleptic exposure here.
**C.** Correct. Ice-water immersion provides the fastest reduction of core temperature and is the proven mortality-reducing therapy for exertional heat stroke.
**D.** Hemodialysis may be required later for rhabdomyolysis-driven AKI or hyperkalemia, but is not the immediate priority while the patient remains hyperthermic.