Thyroid storm vs Myxedema coma
How to tell Thyroid storm and Myxedema coma apart when a board question makes them look alike.
Step 2 CK pairs are in open beta while clinical review finishes. Spot an issue? Tell us.
Core temperature direction at presentation, high fever versus hypothermia, separates the emergency state.
Side by side
Hyperthermia with marked tachycardia, delirium, and decompensation in untreated thyrotoxicosis indicates thyroid storm.
Hypothermia, bradycardia, hypoventilation, and altered consciousness in severe hypothyroidism indicate myxedema coma.
Sudden catecholamine-sensitive hypermetabolism from excess thyroid hormone causes multisystem adrenergic collapse.
Critical thyroid hormone deficiency lowers cardiac output and ventilation, causing CO2 retention and cerebral dysfunction.
Suppressed TSH with elevated free T4 or T3 supports severe thyrotoxicosis; Burch-Wartofsky score above 45 strongly supports storm.
Very high TSH with low free T4, sodium often below 130 mEq/L, glucose often below 60 mg/dL, and PaCO2 elevation from hypoventilation support myxedema coma.
The trap
Both can present with altered mental status, so learners anchor on confusion alone; pulse and temperature resolve the branch, with severe tachycardia and fever favoring storm and bradycardia with hypothermia favoring myxedema coma.
The repair move
Next best step: secure airway and support ventilation, give IV levothyroxine 200 to 400 mcg loading dose, add IV hydrocortisone 100 mg every 8 hours until adrenal insufficiency is excluded, then rewarm gradually and correct hyponatremia and hypoglycemia in ICU monitoring.
Try a free question
CoreA 72-year-old man with long-standing hypothyroidism is found confused and somnolent in winter. BP 90/58 mm Hg, HR 46/min, temp 34.4 C, RR 9/min. Labs show Na 124 mEq/L, glucose 58 mg/dL, TSH 52 mIU/L, free T4 low. What is the next best step in management?
Show answer and explanation
Answer: A. Start IV levothyroxine plus IV hydrocortisone after airway support. Myxedema coma requires immediate supportive care plus IV thyroid hormone and stress-dose glucocorticoids.
Why the other choices are tempting
- B. Wrong because methimazole and propranolol treat hyperthyroid storm, not severe hypothyroid decompensation.
- C. Wrong because waiting risks respiratory arrest and worsening shock in a life-threatening endocrine emergency.
- D. Wrong because uptake scanning is not part of immediate stabilization in an unstable patient.
- E. Wrong because oral absorption is unreliable in coma and steroids should be added before full replacement.
Flashcards
Tap a card to flip it.
In a critically ill patient with thyroid dysfunction and altered mental status, which vital-sign pattern points to thyroid storm rather than myxedema coma?
High fever with marked tachycardia points to thyroid storm, while hypothermia with bradycardia points to myxedema coma.
Which bedside respiratory clue supports myxedema coma in severe hypothyroidism?
Hypoventilation with CO2 retention and depressed mental status supports myxedema coma.
Quick answers
What is the fastest way to tell Thyroid storm from Myxedema coma?
Core temperature direction at presentation, high fever versus hypothermia, separates the emergency state.
What is the key clue for Thyroid storm?
Hyperthermia with marked tachycardia, delirium, and decompensation in untreated thyrotoxicosis indicates thyroid storm.
What is the key clue for Myxedema coma?
Hypothermia, bradycardia, hypoventilation, and altered consciousness in severe hypothyroidism indicate myxedema coma.
What is the common trap with Thyroid storm vs Myxedema coma?
Both can present with altered mental status, so learners anchor on confusion alone; pulse and temperature resolve the branch, with severe tachycardia and fever favoring storm and bradycardia with hypothermia favoring myxedema coma.