Failure to thrive

A descriptive diagnosis of pediatric undernutrition characterized by inadequate weight gain or decelerated growth (weight, length/height, or BMI for age). Possible causes are insufficient nutrient intake (feeding issues), malabsorption (celiac disease, cystic fibrosis, milk protein allergy, severe acid reflux, genetic or inborn errors in metabolism), or increased metabolic demands (congenital heart/lung disease, chronic kidney disease, HIV, tuberculosis, hyperthyroidism, Down syndrome).