Hypokalaemia and failure to thrive: Report of a misleading onset

Aim: We report a case of Gitelman Syndrome (GS) in a 9-year-old girl, previously diagnosed as a Bartter syndrome at one year of life. Methods: She had been treated with potassium, for over 8 years and was admitted because of fatigue, numbness and weakness of both legs. The patient has typical laboratory findings, including hypokalemia, metabolic alkalosis, hypomagnesemia, and hypocalciuria, thus GS was suspected. Results: Genetic analysis was performed two mutations IVS9(+1)G>T were detected in the thiazide-sensitive Na-Cl cotransporter (TSC) gene (SLC12A3), thus she was diagnosed as having GS. She was treated with oral potassium and magnesium supplements with resolution of the symptoms. Conclusion: This case reminded us that doctors should be alert to the initial presentation of renal tubular diseases. Detailed electrolyte analysis, hormone evaluations and clinic follow-up are mandatory for their correct differential diagnosis. © 2010 Paediatrics and Child Health Division (Royal Australasian College of Physicians).