Which acid-base disturbance is most characteristic of diarrheal losses?

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Multiple Choice

Which acid-base disturbance is most characteristic of diarrheal losses?

Explanation:
Diarrheal losses remove bicarbonate from the body in stool, so serum bicarbonate falls and pH drops, producing a metabolic acidosis. Because chloride rises to keep electroneutrality as bicarbonate is lost, this becomes a hyperchloremic, non‑anion‑gap metabolic acidosis. The respiratory system tries to compensate by increasing ventilation to blow off CO2, but the primary disturbance remains metabolic acidosis. Vomiting, in contrast, removes hydrogen and chloride, leading to metabolic alkalosis with increased bicarbonate, which is why that scenario does not fit diarrheal losses. Respiratory acidosis would arise from CO2 retention due to hypoventilation, not from GI bicarbonate loss.

Diarrheal losses remove bicarbonate from the body in stool, so serum bicarbonate falls and pH drops, producing a metabolic acidosis. Because chloride rises to keep electroneutrality as bicarbonate is lost, this becomes a hyperchloremic, non‑anion‑gap metabolic acidosis. The respiratory system tries to compensate by increasing ventilation to blow off CO2, but the primary disturbance remains metabolic acidosis. Vomiting, in contrast, removes hydrogen and chloride, leading to metabolic alkalosis with increased bicarbonate, which is why that scenario does not fit diarrheal losses. Respiratory acidosis would arise from CO2 retention due to hypoventilation, not from GI bicarbonate loss.

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