What is the predominant acid-base disturbance in isolated septic shock?

• A. Metabolic acidosis
• B. Respiratory alkalosis
• C. Metabolic alkalosis
• D. Mixed metabolic and respiratory acidosis

Answer: (A)

Tissues receive insufficient oxygen in septic shock, so cells shift to anaerobic metabolism and produce lactate. This lactate accumulation brings hydrogen ions into the circulation and consumes bicarbonate, causing a drop in pH with an elevated anion gap—classic metabolic acidosis. The body will respond with rapid breathing to blow off CO2, a compensatory change that helps offset the acidosis but does not change the primary problem. Respiratory alkalosis isn’t the main issue here, and metabolic alkalosis isn’t expected in this scenario. A mixed pattern could occur in more complex cases, but in isolated septic shock the dominant disturbance is metabolic acidosis from lactic acid.