Which acid-base disturbance is most commonly associated with diabetic ketoacidosis?

• A. Metabolic alkalosis.
• B. Respiratory acidosis.
• C. High anion gap metabolic acidosis.
• D. Normal anion gap metabolic acidosis.

Answer: (C)

Diabetic ketoacidosis leads to a metabolic acidosis with a high anion gap. When insulin is deficient, the body ramps up lipolysis and ketogenesis, producing ketone bodies that accumulate as organic acids. Those acids release H+, bicarbonate is used to buffer them, so bicarbonate drops. The result is an increased anion gap because ketones add unmeasured anions to the serum. The body attempts to compensate by breathing faster and deeper to blow off CO2, but the core issue is the metabolic acidosis from ketone accumulation. Other disturbances don’t fit this pattern: metabolic alkalosis would raise pH and bicarbonate; respiratory acidosis comes from CO2 retention; normal anion gap acidosis occurs with bicarbonate loss and chloride retention, not with ketone buildup.