Bartter's syndrome with normal chloride reabsorption during indomethacin treatment

A 17-year-old male patient with Bartter's syndrome was admitted for renal function studies. This patient had persistent hypokalemia, first found at age 5; the diagnosis of Bartter's syndrome with renal hypersecretion of prostaglandins E2 and F2 alpha had been established at age 13. A congenital defect of chloride reabsorption was expected, but after 4 years of indomethacin treatment no such defect was found. Withdrawal of indomethacin for 1 week resulted in profound hypokalemia and the appearance of a chloride reabsorption defect, with an excessive urinary PGE2 and PGF2 alpha excretion, and a parallel decrease in plasma prostaglandin precursors. The cause of Bartter's syndrome in this patient seems to be renal hyperprostaglandinism.