52-year-old man with confusion and bradycardia
A 52-year-old man is brought to the emergency department for confusion. His wife reports he has seemed "off" all day. He has a history of hypertension and stage 3 chronic kidney disease. A recent medication review shows he takes lisinopril, and spironolactone was added two weeks ago. He also uses a salt substitute. He is lethargic. Temperature is 37.1°C (98.8°F), blood pressure is 110/68 mmHg, pulse is 54/min, and respirations are 18/min. Neurologic examination is nonfocal. An electrocardiogram shows sinus bradycardia with peaked T waves and a QRS duration of 140 ms. Laboratory results include a potassium level of 7.8 mEq/L and creatinine of 2.9 mg/dL (baseline 1.5 mg/dL). Which of the following is the most appropriate next step in management?
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Post-Call Recovery Reads
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C
Explanation
Clinical Pearl:
In severe hyperkalemia, EKG changes such as a widened QRS complex indicate impending cardiovascular collapse. Intravenous calcium must be administered immediately to stabilize the cardiac membrane before any other potassium-lowering therapies are initiated.
Explanation:
This patient has life-threatening hyperkalemia (K+ 7.8 mEq/L) with EKG evidence of cardiotoxicity, including bradycardia and a widened QRS complex. The presence of EKG changes from hyperkalemia mandates immediate administration of intravenous calcium gluconate to stabilize the cardiac membrane and prevent malignant arrhythmia. This is the most critical first intervention. While administering insulin and dextrose will lower the serum potassium, this therapy does not provide immediate cardioprotection and should be given after calcium. Arranging for emergent hemodialysis is the definitive treatment but is not the most immediate step, as it takes time to initiate. Sodium polystyrene sulfonate acts too slowly for this emergency. A sodium bicarbonate infusion is not a first-line therapy for hyperkalemia and is less effective than other available options.
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