Failure to thrive

Failure to thrive (FTT) indicates insufficient weight gain or inappropriate weight loss in pediatric patients unless the term is more precisely defined. In children, it is usually defined in terms of weight, and can be evaluated either by a low weight for the child's age, or by a low rate of increase in the weight.
The term "failure to thrive" has been used vaguely and in different contexts to refer to different issues in pediatric growth. It is most commonly used to describe a failure to gain weight, but some providers have also used it to describe a failure to grow, or a failure to grow and to gain weight. As used by pediatricians, it covers poor physical growth of any cause. The term has been used in different ways, and different objective standards have been defined. FTT is suggested by a fall in one or more weight centile spaces on a World Health Organization (WHO) growth chart depending on birth weight or when weight is below the 2nd percentile of weight for age irrespective of birth weight. In children whose birth weight was between the 9th and 91st percentile FTT is indicated by a drop across 2 or more centile spaces. Weight loss after birth is normal and most babies return to their birth weight by three weeks of age. Clinical assessment for FTT is recommended for babies who lose more than 10% of their birth weight or do not return to their birth weight after three weeks. Failure to thrive is not a disease, but a sign of inadequate nutrition. 
In veterinary medicine it is also referred to as ill-thrift.
Signs and symptoms.
Failure to thrive occurs in children whose nutritional intake is insufficient for supporting normal growth and weight gain. Failure to thrive typically presents before two years of age, when growth rates are highest. Parents may express concern about picky eating habits, poor weight gain, or smaller size compared relative to peers of similar age. Physicians often identify failure to thrive during routine office visits, when a child's growth parameters are not tracking appropriately on growth curves. Physicians look for many signs on physical exam that can indicate a potential cause of FTT. For example, findings such as scaling skin, spoon-shaped nails, cheilosis and neuropathy may indicate potential vitamin and mineral deficiencies. Fetal alcohol syndrome (FAS) has also been associated with FTT, and can present with characteristic findings including microcephaly, short palpebral fissures, a smooth philtrum and a thin vermillion border. Malabsorption, due to disorders like Crohn's disease and cystic fibrosis, can present with abdominal distention and hyperactive bowel sounds. It is also important to differentiate stunting from wasting, as they can indicate different causes of FTT. "Wasting" refers to a deceleration in stature more than 2 standard deviations from median weight-for-height, whereas "stunting" is a drop of more than 2 standard deviations from the median height-for-age. The characteristic pattern seen with children with inadequate nutritional intake is an initial deceleration in weight gain, followed several weeks to months later by a deceleration in stature, and finally a deceleration in head circumference. A decrease in length with a proportional drop in weight can be related to long-standing nutritional factors as well as genetic or endocrine causes. Head circumference, as well, can be an indicator for the etiology of FTT. If head circumference is affected initially in addition to weight or length, other factors are more likely causes than inadequate intake. Some of these include intrauterine infection, teratogens, and some congenital syndromes.
Cause.
Traditionally, causes of FTT have been divided into endogenous and exogenous causes. These causes can be largely grouped into three categories: inadequate caloric intake, malabsorption/caloric retention defect, and increased metabolic demands. Initial investigation should consider prenatal history, postnatal history, past medical history, feeding history to assess overall caloric intake, developmental history, family history, and psychosocial history.
Diagnosis.
FTT may be evaluated through a multifaceted process, beginning with a patient history that notably includes diet history, which is a key element for identifying potential causes of FTT. Next, a complete physical examination may be done, with special attention being paid to identifying possible organic sources of FTT. This could include looking for dysmorphic features, abnormal breathing sounds, and signs of specific vitamin and mineral deficiencies. The physical exam may also reveal signs of possible child neglect or abuse. Based on the information gained from the history and physical examination, a workup can then be conducted, in which possible sources of FTT can be further probed through blood work, X-rays, or other tests. Laboratory workup should be directed by concerning history and physical examination findings, as it is estimated that the usefulness of laboratory investigations for children with failure to thrive is 1.4%. Initial bloodwork should be based on the clinical picture of the child. Common bloodwork should include a CBC with differential, a complete metabolic panel to look for electrolyte derangements, a thyroid function test, and a urinalysis. If indicated, anti-TTG IgA antibodies can be used to assess for celiac disease, and a sweat chloride test is used to screen for cystic fibrosis. If no cause is discovered, a stool examination could be indicated to look for fat or reducing substances. C-reactive protein and erythrocyte sedimentation rate (ESR) can also be used look for signs of inflammation.
Treatment.
Infants and children who have had unpleasant eating experiences (e.g. acid reflux or food intolerance) may be reluctant to eat their meals. Additionally, force feeding an infant or child can discourage proper self-feeding practices and in-turn cause undue stress on both the child and their parents. Psychosocial interventions can be targeted at encouraging the child to feed themselves during meals. Also, making mealtimes a positive, enjoyable experience through the use of positive reinforcement may improve eating habits in children who present with FTT. If behavioral issues persist and are affecting nutritional habits in children with FTT it is recommended that the child see a psychologist. If an underlying condition, such as inflammatory bowel disease, is identified as the cause of the child's failure to thrive then treatment is directed towards the underlying condition. Special care should be taken to avoid refeeding syndrome when initiating feeds in a malnourished patient. Refeeding syndrome is caused by a shift in fluid and electrolytes in a malnourished person as they receive artificial refeeding. It is potentially fatal, and can occur whether receiving enteral or parenteral nutrition. The most serious and common electrolyte abnormality is hypophosphatemia, although sodium abnormalities are common as well. It can also cause changes in glucose, protein, and fat metabolism. Incidence of refeeding syndrome is high, with one prospective cohort study showing 34% of ICU experienced hypophosphatemia soon after feeding was restarted.
Prognosis.
Children with failure to thrive are at an increased risk for long-term growth, cognitive, and behavioral complications. Studies have shown that children with failure to thrive during infancy were shorter and lower weight at school-age than their peers. Failure to thrive may also result in children not achieving their growth potential, as estimated by mid-parental height. Longitudinal studies have also demonstrated lower IQs (3–5 points) and poorer arithmetic performance in children with a history failure to thrive, compared to peers receiving adequate nutrition as infants and toddlers. Early intervention and restoration of adequate nutrition has been shown to reduce the likelihood of long-term sequelae, however, studies have shown that failure to thrive may cause persistent behavioral problems, despite appropriate treatment.
Epidemiology.
Failure to thrive is a common presenting problem in the pediatric population. Failure to thrive is very prevalent in the United States, representing 5–10% of children seen as outpatients by primary care physicians. Failure to thrive is more prevalent in children of lower socioeconomic status and is associated with lower parental education levels. Failure to thrive accounts for 3–5% of all hospital admissions for children under two years of age. Retrospective studies suggest that males are slightly more likely than females to be admitted to the hospital for failure to thrive (53.2% vs. 46.7%).
History.
FTT was first introduced in the early 20th century to describe poor growth in orphan children but became associated with negative implications (such as maternal deprivation) that often incorrectly explained the underlying issues. Throughout the 20th century, FTT was expanded to include many different issues related to poor growth, which made it broadly applicable but non-specific. The current conceptualization of FTT acknowledges the complexity of faltering growth in children and has shed many of the negative stereotypes that plagued previous definitions.