A Case of Failure to Thrive- Investigation Beyond a Positive Sweat Test

Abstract

Failure to thrive represents a difficult entity to define and can be associated with several diseases. Therefore, combining all the data (family history, perinatal and infancy information) with the physical examination and laboratory findings is a fundamental step to reach the correct diagnosis. A comprehensive and structured diagnostic approach is required in order to select between cystic fibrosis, innate errors of the metabolism or malabsorption syndromes as possible causes. The sweat test is the goldstandard method to diagnose cystic fibrosis although it is widely recognized that there are some inherent limitations to the test. For that reason, it is important to discuss unexpected results and to reassess, when possible, the exams previously performed, which can be crucial to make the diagnosis. Here, the authors report a patient with minor dysmorphic features associated with failure to thrive and a positive result for the sweat test and its following investigation to achieve the definite diagnosis of Bartter syndrome.