Which electrolyte abnormality is most likely to occur in CKD due to reduced renal excretion of potassium?

• A. Hyponatremia due to dilution
• B. Hypercalcemia due to vitamin D excess
• C. Hyperkalemia due to reduced renal potassium excretion
• D. Hypomagnesemia due to poor intake

Answer: (C)

Potassium balance is mainly controlled by renal excretion. In chronic kidney disease, the glomerular filtration rate and the kidney’s ability to secrete potassium in the distal nephron are impaired, so potassium accumulates in the blood. This produces hyperkalemia, a common and clinically important issue in CKD that can cause dangerous heart rhythm changes if not managed.

Hyponatremia due to dilution isn’t the primary result of reduced potassium excretion. Hypercalcemia from vitamin D excess isn’t typical in CKD— impaired vitamin D activation and phosphate retention more commonly cause hypocalcemia with secondary hyperparathyroidism. Hypomagnesemia from poor intake is less likely because CKD tends to raise magnesium levels as excretion falls.