Electrocardiographical case. A tale of tall T's. Hyperkalaemia.

A 63-year-old woman presented at the emergency department (ED) with a history of increasing lethargy and drowsiness. The electrocardiogram (ECG) showed tall peaked T waves with broadening of the QRS interval, suggestive of hyperkalaemia. This patient had an elevated serum potassium level due to diabetic ketoacidosis. She was treated with intravenous calcium chloride and insulin with 50% dextrose. The ECG changes associated with hyperkalaemia are discussed, with illustrations from a second 48-year-old male patient with renal failure who presented with malaise, lethargy and generalised weakness.