What is the net acid-base disturbance typically seen in salicylate overdose?

• A. Mixed Respiratory Alkalosis + Metabolic Acidosis
• B. Metabolic Acidosis only
• C. Respiratory Alkalosis only
• D. Metabolic Alkalosis

Answer: (A)

In salicylate overdose two processes happen at once, creating a mixed acid-base picture. The drug stimulates the respiratory center, so the patient hyperventilates and blows off CO2, producing a respiratory alkalosis. At the same time, salicylates disrupt cellular energy and promote the formation of organic acids like lactate, leading to a high anion gap metabolic acidosis. Because both disturbances occur together, the arterial blood gas often shows a low CO2 and a low bicarbonate, with the pH that may be near normal or only mildly acidotic. This combination—respiratory alkalosis plus metabolic acidosis—is the typical net disturbance in salicylate overdose.