Severe Hyperkalemia With Cardiac Conduction Abnormalities in a 92-Year-Old Woman: First Reported Case in Illinois, United States.

Hyperkalemia, defined as a serum potassium level greater than 5.0 mEq/L, disrupts electrolyte balance and may cause neuromuscular symptoms, including palpitations, fatigue, or weakness. Severe cases exceeding 6.5 mEq/L can lead to life-threatening arrhythmias and cardiac arrest if left untreated. We present a 92-year-old female with stage 4 chronic kidney disease, diastolic heart failure, and a chronic right leg ulcer who arrived at the emergency department with lethargy and intermittent confusion following a fall. Laboratory results revealed a potassium level of 9.7 mEq/L, an estimated creatinine clearance of 9.4 mL/minute, a renal function index of 10.5, a bicarbonate level of 10.9 mEq/L, and a pH of 7.19. ECG demonstrated sinus bradycardia at 40 bpm, low-amplitude P waves, mild PR prolongation, and tall, narrow, symmetric T waves, most prominent in V2-V3 and multiple limb leads. The patient underwent emergent hemodialysis, which normalized her potassium level to 4.3 mEq/L within 24 hours. A repeat ECG showed resolution of abnormalities and restoration of a sinus rhythm at 95 bpm. This case highlights the life-saving importance of rapid ECG recognition, immediate laboratory confirmation, and prompt initiation of therapy in the management of severe hyperkalemia.