Failure to Thrive In Children
Failure to thrive is a complex pediatric diagnosis. It is not an “eyeball” diagnosis. In the broadest terms, FTT refers to infants and children whose growth deviates from the norms for their age and sex. Generally, an evaluation is warranted when a child’s weight falls below the fifth percentile for age or length/height or decreases across more than two major percentile lines on the National Center for Health Statistics (NCHS) charts after 18 months of age (i.e. from the 50th percentile to the 10th percentile). According to some surveys, FTT occurs in nearly 10% of low-income young children, but does not occur only in low-income families. Diagnosis of FTT begins with anthropometric measurements and growth parameters.
If, after consideration of the child’s growth parameters, the clinician is concerned about FTT, there are four dimensions to be considered: medical, nutritional, developmental, and social. Every child with FTT, and family with a child carrying this diagnosis, should be assessed on all four of these parameters. Although the child’s current nutritional status is most literally interpreted as inadequate nutritional sustenance to maintain normal growth given the child’s nutritional needs (which may be increased by illness), there are many factors that can contribute to this diagnosis. Also important are the collaborative efforts of clinicians gathering and compiling this information. Optimal care involves a well-coordinated multidisciplinary team where all clinicians communicate regularly with each other, the family, and collateral services.
Consideration of abuse or neglect as a cause for failure to grow is necessary. We suggest, however, that child abuse is not a common cause. Initially approaching a family with a child with FTT as though you perceive them as abusive or neglectful will not effectively engage the family in the complex process of diagnosis and treatment. Abuse and neglect should be considered when there is “intentional withholding of food from the child; strong beliefs in health and/or nutrition regimens that jeopardize a child’s well-being; and/or family that is resistant to recommended interventions despite multidisciplinary team approach. and/or inflicted trauma or grossly inadequate hygiene.” (an adaptation from Block and Krebs by Black, et al.)
The most crucial component of the medical evaluation of a child with FTT is a physical examination coupled with a detailed prenatal and postnatal history. Laboratory testing should be performed on the basis of the history and physical examination. Hospitalizations and tube feeding are rarely necessary for treatment of FTT, except for the most severely affected or complex cases. The experience of hospitalization can in fact be a hindrance in many cases.
A nutritional history should begin just after birth; was the child breastfed or bottle-fed? When was the child transitioned to whole cow milk? Is the child on any vitamins? When were solid foods first introduced? There are some “red flags” commonly associated with FTT. These often include over dilute formula, improper mixing of formula, and excessive intake of juice, water, juice drinks, tea, or carbonated beverages. A complete nutritional history will scan for possible developmentally inappropriate food choices, food allergies, grazing (a lack of stable feeding schedule leading to all day snacking, depressed appetite, and inadequate caloric intake), reflux, dietary iron, zinc, calcium, or vitamin deficiency, and gluten sensitivity.
Underlying developmental issues may be either contributing to the child’s FTT or evolve consequent to their depleted nutritional status. Subtle neurologic disturbances in oral motor function may contribute to FTT, as can major neurologic disorders and dysmorphic syndromes associated with developmental delay. Not only can developmental issues contribute to FTT, but many developmental delays can be attributed to FTT. Clinicians must be cognizant that children diagnosed with FTT are at risk for blunted affect, language delays, motor delays, decreased social interaction, impaired attention and school impairments through school age and into adulthood. Brain growth is at its greatest between the last three months of gestation and 36 months of life. During this time, malnutrition can lead to decrements in myelination, evolving brain structures, and neurotransmitter networks. It has been shown that refeeding alone does not ameliorate established developmental deficits in children with FTT relative to well nourished peers, but that refeeding coupled with extended developmental intervention can significantly decrease the later developmental gaps between children with FTT and their peers. Therefore, developmental assessment and enrichment should begin as soon after FTT identification as possible.
Acquiring a social history from parent/guardian of a child with FTT can be a very sensitive task. Clinicians should be mindful that parents may be reluctant to engage in such a discussion, feeling that it will lead to accusations of parental failure and possible protective service interventions with ultimate loss of custody of the child. Poverty remains the most common social risk factor for FTT, but is not present in all cases.
Caring for children with FTT must be consistent and cooperative. A multidisciplinary team is essential. Developmental intervention and enrichment should be started at diagnosis. With coordinated care from family and a multidisciplinary team, 90% of children will show positive increments in growth relative to the national norms. The goal of everyone involved must be a thriving child in a thriving environment.
Clinicians should use the current growth charts published by the NCHS for sex and age. The charts are available online (www.cdc.gov/growthcharts). By international consensus, the NCHS growth charts are used to evaluate the growth of young children, regardless of ethnic or racial background. Concerns have been raised that exclusively breast fed infants might be considered to be failing to grow when weights are at or slightly below the 5th percentile on the NCHS graph. The WHO curves drawn for breast-fed infants suggest that there is a slight downward shift in the curves past 6 months of age. [See Assessment of Nutritional Status and Breast-feeding modules for these graphs.]
Children should be weighed naked up to 24 months and in underwear only beyond that age. Recumbent length is to be used for children up to 24 months and standing height is to be used beyond that age. Head circumference should also be measured for all children and charted for children up to 36 months. Four growth parameters should be plotted: weight-for-age, height-for-age, weight-for-height (or BMI beyond age 5 years), and head circumference. The most useful growth parameters are sequential. Static measures are useful to assay nutritional status in a community. Dynamic measures are needed to assess the individual. They help the clinician consider the child’s current nutritional status as well as his or her growth trajectory.
It is also important to remember to correct for prematurity. Children’s parameters will look significantly different after this is done. To correct for prematurity, subtract the number of weeks of gestation from 40 weeks and use this number to correct for growth parameters in following measurements:
correct for weight-for-age until 24 months chronological age,
correct for height-for-age until 42 months chronological age,
and correct for head circumference until 18 months chronological age.
Note: Weight-for-height is not dependent on age or gestational age, and therefore does not need correction.
Children with FTT often fall below the third percentile. Therefore, a standardized system for describing children with FTT has been established, initially developed by Gomez and Waterlow. [See Assessment of Nutritional Status – Part 2, Part 2] Anthropometric measurements are defined as “percent standards,” and are measured as percent of the median. For example, to calculate a child’s weight-for-age, we would divide his/her current weight by the median weight for chronological (or corrected) age and sex and multiply by 100. This can be done for all four anthropometric measurements and help clinicians identify the degree of malnutrition. Please see Table 1 to identify degrees of malnutrition based on percent standards. For research purposes, z scores (standard deviation units) calculated from the NCHS
CAPTION: Note use of “Percent of Standard” rather than “Percentiles for age and gender.” “Below 5th %ile” (roughly 90% of standard) is insufficient information to determine degree of malnutrition. Moreover, “Percent of Standard” measures can be used to determine the level of undernutrition for individuals and the community.
The physical examination will, of course, begin with growth parameters and vital signs including temperature, pulse, respirations, and blood pressure (over 24 months). Please see Table 2 for the remainder of the physical examination checklist. A prenatal history is an important component of the medical evaluation. Please see Table 3 for the prenatal history checklist. The final component of the medical evaluation is the postnatal history. Please see Table 4 for postnatal history checklist. These checklists can be extremely valuable for clinicians evaluating children with FTT.
Basic screening should include CBC with differential, lead, FEP, urinalysis, electrolytes, BUN, creatinine, and a PPD. Clinicians should also have a low threshold for obtaining a urine culture, HIV screening, sweat test, secretory IgA, and anti-transglutaminase antibody to rule out occult celiac disease. If the child is a new immigrant or recent traveler, lives in a homeless shelter, has been camping, or is in daycare and has a history of diarrhea or abdominal pain, evaluation for enteric pathogens (e.g. Giardia lamblia, Cryptospiridium parvum) should be considered. Screening for hepatitis and Heliobacter pylori (H. pylori) should also be considered if suggested by history of anorexia or abdominal pain. Although otherwise healthy children with H. pylori may be left untreated, there is recent evidence that H. pylori is correlated with iron deficiency and growth retardation. Therefore, physicians should consider treating H. pylori in children who are also failing to thrive.