What typically causes metabolic alkalosis?

• A. Excessive exercise
• B. Renal failure
• C. Diuretic use
• D. High carbon dioxide levels

Answer: (C)

Metabolic alkalosis is characterized by an increase in bicarbonate levels in the blood or a loss of hydrogen ions, leading to an elevated pH. Diuretic use is a common cause of metabolic alkalosis because certain diuretics, particularly loop diuretics and thiazide diuretics, promote the excretion of sodium and potassium, which can lead to the loss of hydrogen ions and ultimately result in an increase in the bicarbonate concentration.

In this process, the kidneys may retain bicarbonate in response to volume depletion caused by diuretic use, further elevating the pH and contributing to metabolic alkalosis. Additionally, if the diuretic use leads to significant hypokalemia (low potassium levels), this can also exacerbate the condition, as potassium and hydrogen ions have an interconnected relationship in acid-base balance.

Other options, such as excessive exercise, renal failure, or high carbon dioxide levels, do not typically lead to metabolic alkalosis. While renal failure can result in metabolic acidosis due to the accumulation of acids and retention of hydrogen ions, high carbon dioxide levels generally indicate respiratory acidosis rather than metabolic alkalosis. Therefore, the impact of diuretics on electrolyte balance makes them a significant cause of metabolic alkalosis.