A 52-year-old man with diabetic nephropathy misses two dialysis sessions and presents with weakness. ECG shows tall peaked tented T waves, absent P waves, and a widened QRS complex progressing toward a sine-wave pattern. Which electrolyte abnormality explains this sequence?
- A Hyperkalemia ✓
- B Hypercalcemia
- C Hypermagnesemia
- D Hypokalemia
Correct answer: A. Hyperkalemia
Explanation
Progressive hyperkalemia produces peaked T waves, then loss of P waves with widening of the QRS, and finally a sine-wave pattern preceding ventricular fibrillation or asystole. Immediate management includes IV calcium gluconate to stabilize the myocardium, insulin with glucose to shift potassium intracellularly, and definitive removal by dialysis. Hypercalcemia shortens the QT interval rather than producing these changes.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.