Hypokalemia is almost always the result of what?

• A. Abnormal potassium losses via the urine or stool
• B. Decreased dietary potassium intake
• C. Transcellular shift of potassium into cells
• D. Hyperkalemia

Answer: (A)

Potassium balance is about keeping most potassium inside cells and limiting what is lost from the body. The most common reason for low serum potassium is net body loss, especially through the kidneys or the GI tract. Diuretic use or conditions that cause renal potassium wasting, as well as significant stool losses from diarrhea, routinely lead to hypokalemia. Dietary insufficiency alone is unlikely to cause persistent low potassium because intake is usually adequate and the body can compensate. Transcellular shifts—potassium moving into cells due to insulin, alkalosis, or certain drugs—can lower potassium briefly but are not the typical, ongoing cause. Hyperkalemia is the opposite condition and cannot explain hypokalemia. So the frequent culprit is abnormal potassium losses via urine or stool.