Hyperosmolar hyperglycemic state — USMLE Step 2 CK MCQ

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EasyInternal MedicineHyperosmolar hyperglycemic stateUSMLE Step 2 CK

A 64-year-old man with advanced kidney disease has weakness and palpitations. Potassium is 7.4 mEq/L. ECG shows absent P waves and progressive QRS widening. He has a pulse and intravenous access. Which medication should be administered first?

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Correct answer: E — Intravenous calcium gluconate

Severe hyperkalemia with absent P waves and QRS widening threatens progression to a sine-wave rhythm, ventricular fibrillation, or asystole. Intravenous calcium should be given immediately to stabilize the cardiac membrane; peripheral calcium gluconate is commonly used, whereas calcium chloride is more concentrated and is generally given through secure central access or during arrest. Calcium does not lower serum potassium, so insulin with glucose and often nebulized albuterol should follow promptly to shift potassium intracellularly, with frequent glucose monitoring. Definitive potassium removal—urgent hemodialysis in this anuric patient—must also be arranged. Oral binders act too slowly and cannot be sole emergency therapy. Insulin without glucose planning and monitoring risks severe hypoglycemia. Furosemide cannot produce useful kaliuresis in anuria. Calcium may be repeated if toxic ECG changes persist.

Reference: American Heart Association. What Is Hyperkalemia? https://www.heart.org/cpr/-/media/Files/Health-Topics/Answers-by-Heart/What-is-Hyperkalemia.pdf