Which condition would cause a high anion gap metabolic acidosis?

Which condition would cause a high anion gap metabolic acidosis?

• A. Lactic acidosis
• B. Renal tubular acidosis
• C. GI bicarbonate loss
• D. Hyperchloremic acidosis

Answer: (A)

High anion gap metabolic acidosis happens when unmeasured anions accumulate in the blood, such as lactate, ketoacids, or toxins. Lactic acidosis directly adds lactate, an unmeasured anion, while also consuming bicarbonate to buffer the excess hydrogen ions. This combination raises the anion gap computed as Na − (Cl + HCO3), producing a high anion gap. The other conditions listed typically cause a normal (non–high) anion gap metabolic acidosis. Renal tubular acidosis involves bicarbonate loss or impaired acid excretion with chloride replacement, leading to hyperchloremic (normal AG) acidosis. GI bicarbonate loss, such as from diarrhea, also results in bicarbonate depletion with chloride rise, yielding a normal AG. Hyperchloremic acidosis is essentially this same normal-AG pattern. Therefore, lactic acidosis best explains a high anion gap metabolic acidosis.

High anion gap metabolic acidosis happens when unmeasured anions accumulate in the blood, such as lactate, ketoacids, or toxins. Lactic acidosis directly adds lactate, an unmeasured anion, while also consuming bicarbonate to buffer the excess hydrogen ions. This combination raises the anion gap computed as Na − (Cl + HCO3), producing a high anion gap.

The other conditions listed typically cause a normal (non–high) anion gap metabolic acidosis. Renal tubular acidosis involves bicarbonate loss or impaired acid excretion with chloride replacement, leading to hyperchloremic (normal AG) acidosis. GI bicarbonate loss, such as from diarrhea, also results in bicarbonate depletion with chloride rise, yielding a normal AG. Hyperchloremic acidosis is essentially this same normal-AG pattern. Therefore, lactic acidosis best explains a high anion gap metabolic acidosis.