Failure to Thrive (FTT) is not just for the clinics. We need to be on the lookout, because if we find it, there is already a big problem. Definitions of Failure to Thrive may quibble on the details, but for us in the ED: Consistently under 2nd percentile in weight over time "Falling off" the growth curve over 2 or more points We can get around the longitudinal requirement by looking at weight as a "spot check" -- if grossly below weight without any other chronic condition, be alarmed. Failure to thrive results from inadequate calories. This may be due to: Not enough offered Not enough taken Not enough absorbed Any concern should trigger a more complete H&P (in audio). Classic instructional video on the mother-infant dyad (scan through for various types). After a focused H&P, you may need to admit the child for further workup, or to show that he can/cannot gain weight with routine care. Remember, if you are the first one to bring this up, there is a real problem. By definition, an outpatient plan has failed. We will not be able to distinguish among the various possibilities of organic and non-organic causes (or mix thereof); our job is to be ready to catch it and act on it. The child's development, future intelligence, and welfare are at risk. References Birth to 24 months: Boys Weight-for-length percentiles and Head circumference-for-age percentiles Birth to 24 months: Boys Length-for-age percentiles and Weight-for-age percentiles Birth to 24 months: Girls Weight-for-length percentiles and Head circumference-for-age percentiles Birth to 24 months: Girls Length-for-age percentiles and Weight-for-age percentiles Jaffe AC. Failure to Thrive. Pediatrics in Review. 2011; 32(3) Prutsky GJ et al. When Developmental Delay and Failure to Thrive Are Not Psychosocial. Hospital Pediatrics. 2016; (1):6