Hyperkalemia is common early in burn resuscitation due to cell lysis; which electrolyte disturbance occurs later due to diuresis?

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

Answer: (C)

Early in burn resuscitation, cell damage releases potassium into the extracellular space, so serum potassium tends to be high. As resuscitation advances, urine output increases during the diuretic phase, and the kidneys excrete more potassium. Potassium is actively secreted in the distal nephron, and the high flow through the tubules plus aldosterone-driven potassium loss leads to a drop in serum potassium. This makes hypokalemia the typical electrolyte disturbance seen later. Hyperkalemia occurs early, while sodium disturbances can occur for other reasons during resuscitation, but the late change tied to diuresis is a fall in potassium.