Which statement correctly describes the acid-base disturbances seen in chronic kidney disease and the compensatory mechanisms?

• A. Metabolic alkalosis with metabolic compensation for CKD.
• B. Metabolic acidosis with respiratory compensation via hypoventilation.
• C. Metabolic acidosis due to decreased acid excretion and bicarbonate production, with respiratory compensation via hyperventilation.
• D. No acid-base disturbances in CKD.

Answer: (C)

In chronic kidney disease, the kidneys lose their ability to excrete acid and to regenerate bicarbonate. This shifts the balance toward hydrogen ions, producing metabolic acidosis. The body responds by increasing ventilation to blow off carbon dioxide, which lowers the hydrogen ion concentration and helps raise the pH back toward normal. This is metabolic acidosis with respiratory compensation occurring through hyperventilation.

The other scenarios don’t fit CKD: it doesn’t typically cause metabolic alkalosis, hypoventilation would worsen acidosis rather than compensate, and CKD often disrupts acid-base balance rather than leaving it completely normal.