The term “failure to thrive “(FTT) first appeared in the literature more than 80 years ago, and although it continues to be widely used, it has no precise definition. Recent terms to describe FTT include undernutrition, malnutrition, and faltered growth. In 2017, guidelines by the National Institute for Healthcare and Excellence in the United Kingdom were published to aid in recognizing, assessing, and monitoring of “faltering growth” in infants and children in the United Kingdom.1 With a lack of any other formal practice recommendations, however, clinical practice is variable, with an overuse of resources, including unnecessary laboratory testing, subspecialist referrals, and hospitalization.2-4
Historically, FTT has been classified as organic and nonorganic, but it is now recognized that only a small minority of children with FTT have an underlying organic cause. Instead, FTT often has a multifactorial etiology involving a complex interaction between medical, nutritional, emotional, and social issues. Although this range of contributing factors can pose a diagnostic challenge, the evaluation and coordination of a management plan for FTT can often be done successfully by providers across the continuum of pediatric care when guided by findings from a detailed history and thorough physical examination.
With a focus on promoting high-value care for patients, this article presents a practical, systematic approach that pediatric providers can use for the differential diagnosis and management of FTT.
Failure to thrive has classically been identified when a child’s weight drops off the standardized weight curve before and to a greater extent than the length/height (Figure).5 Its recognition depends on reliable serial measurements for growth assessment. Individuals gathering data must be properly trained and use appropriate equipment with a standardized technique. Stature (length/height) should be measured with the child lying supine on a length board for children aged 0 to 2 years and using a stadiometer for older children. Weight should be determined using a digital scale, and head circumference also should be measured in children aged younger than 3 years.
Data should be recorded and plotted on a standardized growth chart for age and gender or using another appropriate chart when special circumstances exist (eg. premature birth, genetic syndrome). The Centers for Disease Control and Prevention (CDC) recommends using the World Health Organization’s weight-for-length growth chart for children aged younger than 2 years and the CDC body mass index (BMI) growth chart for older children.6