Hypokalemic nephropathy in an adult patient with partial empty sella: a classic Bartter's syndrome, a Gitelman's syndrome or both?

Bartter's syndrome belongs to a group of hypokalemic renal channel diseases. These channels are located in the lipid layer of cell membranes where they exist as water channels through which ion transport is performed. Based on the type of genetic disorder and clinical presentation, Bartter's syndrome is classified as neonatal, classical and Gitelman's syndrome. Most of the cases have been noted in pediatric age groups and adult-onset cases are very rare. Moreover, an association between Bartter's syndrome and empty sella has recently been reported in 3 children. We report here the second case of an adult patient affected by Bartter's syndrome with partial empty sella. The patient showed some clinical and histological characteristics of both classic Bartter's syndrome and Gitelman's syndrome, suggesting that genotype and phenotype of Bartter's syndrome are not so clear-cut and that phenotypic overlap may occur, according to a recent hypothesis. Magnetic resonance imaging disclosed a partial empty sella. A thorough endocrinological investigation showed normal hypophyseal, thyroidal, adrenal and gonadal function. Good therapeutic effects were achieved using spironolactone, ACE-inhibitor and potassium supplementation, with normalization of the kalemia. At present, the value of the association of Bartter's syndrome and empty sella remains unclear and future studies are needed to clarify the importance of this association, both in children and in adult patients affected by Bartter's syndrome.