Hypokalemia: A Practical Approach to Diagnosis and Treatment

Abstract

Potassium (K⁺) is the predominant intracellular cation. It is essential to the function of all living cells. Intracellular K⁺ concentration is over 30 times its extracellular concentration. Serum K⁺ is dependent on its intake, excretion, and transcellular distribution. Most of the body’s K⁺ is in the muscles. Aldosterone is the main regulator of K⁺ renal excretion. Hypokalemia (serum K⁺ < 3.5 mEq/l) has multiple manifestations affecting different organ systems. Careful history and basic laboratory tests are usually adequate to diagnose most cases of hypokalemia. K⁺ should be replaced orally whenever feasible. Intravenous K⁺ replacement is needed for emergency management of hypokalemia and in patients who cannot take oral potassium.