An Unusual Presentation of Failure to Thrive in a Toddler: Bartter Syndrome.

Bartter syndrome is a rare salt-wasting renal tubular disorder of autosomal-recessive inheritance. Antenatal Bartter syndrome (types I, II, and IV) manifests in infancy and has a more severe course compared to the classic Bartter syndrome (type III). This report details a unique instance of a male toddler, aged 18 months, who presented with failure to thrive, polydipsia, and polyuria. Blood gases revealed hypochloremic metabolic alkalosis with hyponatremia and hypokalemia. The diagnosis was confirmed by genetic testing, and the child was started on indomethacin and potassium supplementation. Despite being rare in children, this case report emphasizes the importance of looking beyond the usual in a child who presents with failure to thrive to prevent a delay in the diagnosis and treatment.