Vomiting and diuretic use often cause what acid-base disorder, and what are typical electrolyte patterns?

• A. Metabolic alkalosis; hypokalemia, hypochloremia, and compensatory hypoventilation.
• B. Metabolic acidosis; hyperkalemia, hyperchloremia, and hyperventilation.
• C. Respiratory alkalosis; hypokalemia.
• D. Metabolic alkalosis; hyperkalemia, hyperchloremia.

Answer: (A)

Vomiting and diuretic use commonly lead to metabolic alkalosis. Vomiting removes hydrogen ions and chloride from the stomach, so blood bicarbonate rises. Diuretics cause volume depletion and increase losses of chloride and potassium in the urine, promoting hypochloremia and hypokalemia. The body responds to metabolic alkalosis by hypoventilating to retain CO2, which is the compensatory mechanism you’ll see clinically. So the pattern is metabolic alkalosis with low potassium, low chloride, and compensatory hypoventilation. Other options describe the wrong acid-base disorder or the wrong electrolyte changes (for example, hyperkalemia with alkalosis is less typical, and hyperventilation would not be the compensatory response here).