PT - JOURNAL ARTICLE AU - Helena Vieira AU - Leonor Mendes AU - Patricia Mendes AU - José Esteves da Silva TI - Classic Bartter syndrome: a rare cause of failure to thrive in a child AID - 10.1136/bcr.02.2012.5888 DP - 2012 Jun 28 TA - BMJ Case Reports PG - bcr0220125888 VI - 2012 4099 - http://casereports.bmj.com/content/2012/bcr.02.2012.5888.short 4100 - http://casereports.bmj.com/content/2012/bcr.02.2012.5888.full AB - Bartter syndrome is a group of rare autosomal-recessive disorders caused by a defect in distal tubule transport of sodium and chloride. Blood gases and plasma electrolytes raise suspicion of this diagnosis and the definitive diagnosis is made by genetic study. Early treatment improves prognosis. The authors present the case of an 11-month-old child with early failure to thrive and severe regurgitation. Blood gases revealed hypochloraemic metabolic alkalosis, hyponatraemia and hypokalaemia. Blood pressure was normal and polyuria was documented. She began therapy with potassium chloride supplementation and indomethacin. There was clinical improvement and plasma potassium and bicarbonate normalised. The molecular study confirmed it was the classic form of Bartter syndrome. Despite being rare in clinical practice, which may lead to unnecessary medical investigation and diagnosis delay, in a child with failure to thrive, hypochloraemic metabolic alkalosis and hypokalaemia, this diagnosis must be considered.