In diabetic ketoacidosis, monitoring ECG is important to identify complications related to which electrolyte disturbance?

• A. Hyperkalemia
• B. Hyponatremia
• C. Hypercalcemia
• D. Hypokalemia

Answer: (D)

Potassium balance is the key issue in diabetic ketoacidosis when you’re monitoring the heart. At presentation, you may see high potassium in the blood because insulin is lacking and acidosis pushes potassium out of cells. But the body’s total potassium is actually depleted. As you treat DKA with insulin and fluids, potassium moves back into cells, which can cause a dangerous drop in blood potassium—hypokalemia. This shift can trigger serious heart rhythm problems, so ECG monitoring is focused on catching hypokalemia early. On ECG, low potassium can cause flattened or inverted T waves, prominent U waves, ST depression, and can lead to rhythm disturbances. Hyponatremia or hypercalcemia don’t typically drive the acute rhythm disturbances seen during DKA treatment, so the most clinically important electrolyte disturbance to watch for on ECG is hypokalemia.