Renal tubular acidosis typically presents with which acid-base disturbance and chloride status?

• A. Metabolic acidosis with hyperchloremia
• B. Metabolic acidosis with hypochloremia
• C. Metabolic alkalosis with hyperchloremia
• D. Respiratory acidosis with hyperchloremia

Answer: (A)

Renal tubular acidosis causes a metabolic acidosis where the anion gap remains normal. This happens because bicarbonate is lost in the urine or hydrogen ions aren’t adequately secreted, so the body accumulates acid without adding unmeasured anions. To keep electrical neutrality as bicarbonate declines, chloride rises, giving you hyperchloremia. So the characteristic pattern is metabolic acidosis with increased chloride. The other patterns don’t fit: metabolic alkalosis would raise bicarbonate and pH, respiratory acidosis involves CO2 retention rather than bicarbonate loss, and hypochloremia would not accompany the bicarbonate-wasting process seen in RTA.