Hyperkaliuria

Hyperkaluria is a term used to describe an elevated concentration of potassium in urine. It is not a disease in itself but a laboratory finding that can reflect various underlying processes affecting renal potassium handling and overall potassium balance. In healthy individuals, urinary potassium excretion adapts to dietary potassium intake and hormonal regulation, particularly aldosterone. Typical 24-hour urinary potassium excretion ranges roughly from 40 to 120 mEq per day, but values can vary with fluid intake, intake of potassium, and kidney function.

Common causes of hyperkaluria include increased distal potassium secretion driven by aldosterone or higher flow through the distal nephron. This can occur with primary or secondary hyperaldosteronism, and in other high-aldosterone states or conditions that increase distal delivery of sodium and water. Certain medications routinely increase urinary potassium loss, notably loop and thiazide diuretics. Some renal tubular disorders that promote potassium wasting may also present with hyperkaluria, though many potassium-wasting conditions tend to present with hypokalemia. In some cases, a high dietary potassium intake paired with normal kidney function can lead to higher urinary excretion. Transient hyperkaluria can also result from recent diuretic use or measurement variability; laboratory or sampling errors should be considered.

Diagnosis relies on assessing urinary potassium through spot tests or 24-hour collections, and correlating with serum potassium, acid-base status, and medication history. Evaluation often includes checking the renin-angiotensin-aldosterone system to identify hyperaldosteronism. Management targets the underlying cause and the risk of potassium imbalance.