Hypokalemia may be caused by each of the following EXCEPT

• A. Acidosis
• B. Prolonged vomiting or diarrhea
• C. Hypomagnesemia
• D. Hyperaldosteronism

Answer: (A)

Potassium balance depends on how potassium is moved between inside and outside cells and how it’s handled by the kidneys and GI tract. Losing potassium through the GI tract, as happens with prolonged vomiting or diarrhea, directly lowers serum potassium – hypokalemia.

Low magnesium disrupts the kidney’s ability to retain potassium, so reduced Mg leads to potassium wasting and lower serum levels as well.

Hyperaldosteronism increases potassium excretion in the distal nephron, producing hypokalemia.

Acidosis, however, tends to push potassium out of cells into the bloodstream to balance excess hydrogen ions, which usually raises serum potassium (hyperkalemia) rather than lowering it. Because of this shift, acidosis is not a cause of hypokalemia and is the exception in this scenario.