A patient awaiting liver transplant is on diuretics to control ascites and peripheral edema. Which acid-base disorder is expected?

• A. Metabolic acidosis
• B. Metabolic alkalosis
• C. Respiratory acidosis
• D. Respiratory alkalosis

Answer: (B)

When someone with cirrhosis and ascites is treated with diuretics, the body often becomes volume-depleted and chloride-depleted. The kidneys respond by activating the renin–angiotensin–aldosterone system, reabsorbing more sodium, and excreting more hydrogen ions. This sequence raises bicarbonate reabsorption and lowers chloride, leading to a metabolic alkalosis. Loop diuretics specifically increase loss of hydrogen and chloride in the distal nephron, amplifying this effect. Although spironolactone is used to counterbalance potassium loss, the net result in this setting is a contraction alkalosis driven by diuretic therapy. There isn’t a primary respiratory disturbance here, so the expected acid-base disorder is metabolic alkalosis.