We don’t see as much Failure to Thrive nowadays as a decade earlier. The ones that present as underweight are put through a battery of tests before labeling them as ?calorie deficit. Not many of us take detailed dietary history to adjudge caloric intake.

We should think simple things first before subjecting patients to battery of investigations. History taking and its components like food habits are important points.  Read this study highlighting the problems of so called failure to thrive.

Team@CMHF

In a study conducted for failure to thrive, it was found that 2/3 children were not eating properly. Therefore, before considering expensive investigation, these children should be put on supplements, high calorie diet etc.

This study emphasizes that when we have cases of failure to thrive, we should first make sure that these children are fed properly.
To grow properly, one must eat properly. Hypothyroidism and growth hormone deficiency are not very common. Hypothyroidism can be picked up as early as in the neonatal period.

Reference: http://www.medpagetoday.com/MeetingCoverage/LWPES/26251