Beyond the ECG: a Rare Presentation of Severe Hyperkalemia Without Typical Cardiac Changes.

Introduction Hyperkalemia, defined as a serum potassium (K+) concentration exceeding 5.0 or 5.5 mEq/L (mmol/L), is a serious electrolyte disturbance with potentially life-threatening consequences [1]. It is strongly associated with specific electrocardiographic (ECG) findings, most notably peaked T-waves. In more severe cases, changes such as QRS widening and PR interval prolongation may also occur [2]. However, we present the case of an 80-year-old male with severe hyperkalemia (K+ 10 mmol/L), in which the ECG lacked the characteristic peaked T-waves typically associated with this condition. Case Presentation The patient, with an extensive cardiovascular history, presented with syncope, weakness, and hypotension. Initial ECG showed sinus bradycardia and a prolonged PR interval. Laboratory tests confirmed severe hyperkalemia (K+ 10 mmol/L), elevated creatinine (196 µmol/L), and metabolic acidosis. Despite treatment with intravenous fluids, calcium gluconate, Salbutamol, and sodium polystyrene sulfonate, potassium levels remained critically elevated. Nephrology consultation was sought, and hemodialysis was initiated, resulting in a marked reduction in potassium (5 mmol/L) and creatinine (115 µmol/L). A second hemodialysis further stabilized the patient, who was also treated for chronic anemia, potentially related to an underlying malignancy, as well as pyelonephritis. Discussion The absence of typical T-wave changes in the context of severe hyperkalemia is rare and not yet fully understood in the literature [3–5]. One potential explanation is a gradual increase in potassium levels, often seen in chronic kidney disease, which allows the myocardium to adapt and potentially dampen the typical electrophysiological changes. Additionally, pre-existing conduction abnormalities may mask the classic ECG features of hyperkalemia [5]. Conclusions Although the patient's symptoms—syncope and weakness—could be indicative of hyperkalemia, the ECG alone may not accurately reflect the patient's potassium levels due to the absence of peaked T-waves. This reinforces the importance of a comprehensive diagnostic approach, where laboratory testing, in conjunction with ECG interpretation and clinical symptoms, ensures accurate assessment of potassium imbalances.