Final answer:
Diuretics cause metabolic alkalosis by contributing to the excretion of potassium and hydrogen ions, while chloride is lost, and bicarbonate is retained, leading to increased pH in body fluids.
Step-by-step explanation:
Diuretics can cause metabolic alkalosis by promoting the excretion of potassium (K+) in the urine. As K+ levels decrease in the blood, the body tries to retain it, and in the process, more hydrogen (H+) ions are excreted. Also, when treating hypertension with diuretics, the loss of chloride (Cl-) and the body's attempt to retain sodium (Na+) leads to reabsorption of bicarbonate (HCO3-), a base, which increases the pH of the body fluids, leading to alkalosis.
Specifically, diuretics cause prolonged loss of hydrogen and chloride ions, which are components of hydrochloric acid (HCl) in the stomach. When HCl is lost excessively due to prolonged use of diuretics, the body becomes more alkaline. Moreover, increased aldosterone secretion due to conditions such as Cushing's disease can also result in potassium loss and further exacerbate metabolic alkalosis.