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Hyperkalemia with ECG changes — ABIM Board MCQ

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EasyNephrologyHyperkalemia with ECG changesABIM Board

A 69-year-old man with chronic kidney disease and heart failure presents with generalized weakness. His serum potassium concentration is 7.0 mEq/L. An ECG shows peaked T waves and widening of the QRS complexes. His medications include lisinopril and spironolactone. Which of the following interventions should be administered first?

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Correct answer: B — Administer intravenous calcium gluconate

The correct answer is B. Severe hyperkalemia with peaked T waves and QRS widening requires immediate intravenous calcium to stabilize the cardiac myocyte membrane and reduce the risk of ventricular arrhythmia. Calcium acts within minutes but does not reduce the serum potassium level, so it must be followed promptly by potassium-shifting therapy, usually intravenous insulin with dextrose, and a method of potassium elimination. Insulin with dextrose is therefore necessary but is not the first priority when cardiotoxic ECG changes are present. Furosemide may promote potassium excretion only when renal function and urine output are adequate. Sodium polystyrene sulfonate has a delayed, unpredictable effect and is inappropriate as initial emergency therapy. Sodium bicarbonate is not routinely effective unless clinically significant metabolic acidosis is present.

Reference: Rafique Z, et al. Hyperkalemia management in the emergency department: An expert panel consensus. J Am Coll Emerg Physicians Open. 2021;2(5):e12572. https://www.ncbi.nlm.nih.gov/sites/books/NBK557463/