Which of the following is the most common acid-base disturbance in patients with cirrhosis and portal hypertension?

C. Metabolic alkalosis

DISCUSSION: Metabolic alkalosis and hypokalemia are common in patients with cirrhosis because they often have associated secondary hyperaldosteronism (especially those with ascites), diarrhea, and frequent emesis. Hyperaldosteronism enhances H+ and K+ exchange for Na+ in the distal tubule of the kidney. The cause of diarrhea in patients with cirrhosis is unknown, but malabsorption secondary to splanchnic venous hypertension may be a contributing factor. Emesis is common in alcoholic cirrhotics and patients with tense ascites. Deleterious effects of metabolic alkalosis include impaired tissue oxygen delivery secondary to shift of the oxyhemoglobin dissociation curve to the left and conversion of ammonium chloride to ammonia, which may contribute to encephalopathy.