The National Institute of Aging describes failure to thrive (FTT) as a "syndrome of weight loss, decreased appetite and poor nutrition, and inactivity, often accompanied by dehydration, depressive symptoms, impaired immune function, and low cholesterol" . Many of these features of FTT are actually defined as features of frailty including weight loss, malnutrition, and inactivity. In geriatric practice, FTT describes a syndrome of global decline that occurs in older adults as a worsening of physical frailty that is frequently compounded by cognitive impairment and/or functional disability. FTT describes a point further along a geriatric functional continuum that is closer to full dependence and death, with “frailty as a mid-point between independence and pre-death” .
The term FTT has long been used in pediatrics to describe infants who are unable to gain weight and have physical and cognitive developmental impairments and depressive symptoms . Pediatric patients with FTT have not achieved their expected functional level, while elders with FTT are unable to maintain their functional status ; the symptom complex is similar at both ends of the age spectrum.
FTT describes the late stages of decline and may represent a final common pathway toward death. The goal in evaluation and management of FTT is to identify contributing factors that can be modified or reversed, such as assistance with meals to improve nutrition or treatment of infection that may lead to premature death, while keeping in mind the patient and family’s goals and wishes. Some authors cite concerns that the terminology "failure to thrive" impedes appropriate patient evaluation and management , and its use has fallen out of favor. However, we find it a useful term to describe a clinical syndrome encompassing frailty, disability, and neuropsychiatric impairment.
Due to the difficulty in precisely defining FTT as a syndrome in clinical practice, data are limited regarding its incidence, epidemiology, and outcomes. The individual components associated with FTT, however, are clearly predictive of mortality.
This topic will discuss an overview of the evaluation of patients with suspected FTT. Management of older patients with FTT is discussed separately (see "Failure to thrive in elderly adults: Management"), as are discussions cited below on individual components of FTT.