Failure to thrive is a clinical diagnosis which is often an indicator of difficulty with feeding but may also be sign of another underlying pathologic issue. It is characterized by inadequate weight gain when correcting for the child's gestational age, gender, and any relevant medical condition. There is no concensus for the parameters of diagnosis, but common metrics for diagnosis include weight below the 2nd percentile on more than one occasion, or weight dropping more than 2 percentile groups. Typically, weight is affected before length, with head circumference being the last measurement affected.
One way to approach the evaluation of failure to thrive is to consider that the underlying issue is typically a variant of the same basis principle: inadequate usable nutrition. Thus, the etiology may be related to total parenteral intake, to the uptake and/or metabolism of that intake, or to structural abnormalities.
The most important initial step in the evaluation of Failure to Thrive includes a thorough history and physical examination. Important historical points which aid in diagnosis include a detailed dietary history, a detailed birth history including maternal infections and gestational age, and the age of onset of the failure to thrive if it is known.
The most common etiologies of Failure to Thrive lie in the dietary history and relate to inadequate nutritional intake. The physician and the parents should work together to produce an accurate account of all meals, snacks, and drinks. Included in this should be where, when, how and by whom the child is fed. Common problems include overdilution of formula or inappropriate soft food consistency, excessive intake of water, infrequent feedings, lack of set feeding times, distractions at mealtime and regurgitation of food.
A thorough psychosocial history can be very revealing as well. Inadequate access to food, parental depression or drug abuse, and serious parental discord can all affect the frequency of feedings. Some studies site a rate of Failure to Thrive among the impoverished of as high as 10%.
The physical exam is very important with these patients. All growth parameters should be plotted on a gestationally corrected growth chart. A thorough exam of the skin, hair and nails can help with the differential. Scaling skin can indicate zinc deficiency, rough skin or brittle hair can suggest hypothyroidism, edema can indicate severe protein malnutrition. Central cyanosis may be an indicator of congenital heart disease, which may present initially as failure to thrive.
A thorough examination of the nose, mouth and palate can help idenify structural defects which may lead to difficult feeding, such as a cleft lip or palate. Lymphadenopathy, splenomegaly, and ambiguous or prcocious genitalia may be a sign of an underlying endocrine disorder or malignancy.
The examining physician may choose to draw a number of lab tests if the diagnosis is not readily clear from the history and physical. Those tests may include lead, iron studies, electrolytes including BUN/Cr, infectious studies including a UA, PPD or HIV, and thyroxine and TSH.
Differential Diagnosis by Age of Onset:
- Asymmetric IUGR: HC and length normal. Better prognosis.
- Symmetric IUGR: HC and length also restricted. Search for teratogens, congenital viral infections, or genetic syndromes.
- Prenatal exposure to drugs such as cocaine, marijuana, and cigarettes associated with lower birth weight, but not significant impairment in postnatal weight or height.
- When microcephaly predates FTT, it suggests neurologic cause.
- In the postnatal period, correct for prematurity: HC until 18m, weight until 24m, height until 40m.
- Reflects incorrect formula preparation, failed breastfeeding, inadequate number of feedings.
- Bonding problems with mother-infant.
- Impediments to feedings- cleft lip/palate
- Onset around 4 m/o suggests underfeeding- help family with support services.
- If the child has been recently weaned from the breast, milk protein intolerance or improper formula preparation are possibilities.
- Celiac disease, HIV, CF, GER, congenital heart disease, oral-motor dysfunction.
- Onset at 7-9mo. usually suggests an autonomy struggle- educate and counsel.
- Food intolerance to recently introduced solid foods occasionally occurs.
- Weight gain and appetite normally decrease after the first year- parents often become intrusive causing constant battles, food wars.
- Acquired illness, significant stress (birth of sibling) can precipitate weight loss at this age.
Differential Diagnosis by Associated History:
|Spitting, emesis immediately after feeding||GERD||UGI series, pH probe, endoscopy|
|Abdominal distention, cramping, diarrhea||Malabsorption (CF, celiac disease, lactase deficiency)||D-xylose test, stool fat, antigliadin titer or biopsy, sweat test|
|Travel, homeless, shelter, large daycare center||Parasites (esp giardia), TB, poor sanitation||Stool O&P, duodenal biopsy, PPD|
|Snoring, periodic breathing during sleep, noisy breathing||Adenoid hypertrophy||Lateral neck film, sleep study|
|Symptoms of asthma, “bronchitis”||Chronic aspiration, CF, food allergy, GERD||CXR, sweat test|
|Polyuria, polydipsia, polyphagia||Diabetes||Blood glucose|
|Frequent minor infections (malnutrition itself may cause immunodeficiency)||HIV, other immune deficiency||Serologic tests, immunoglobulins, PPD with control for anergy|
The severity of the Failure to Thrive must be evaluated. If it is deemed severe or there is a threat to the safety of the infant, the infant must be hospitalized for evaluation by an interdiciplinary team including pediatricians, social workers and dieticians.
A trial of nutritional therapy often aids in both treatment and diagnosis. A new feeding goal of "catch-up growth" (2-3 times the average rate for age) can be set. Frequency of feedings or caloric density of the food can be increased. Higher density formula can be mixed, or powdered formula can be added to breast milk, to create up to 24-30 calories per ounce. A goal of 50% more than normal intake for age can be used, which for an infant 0-6 months is approximately 108 kcal/kg per day. Multivitamins may be added, but the mainstay of treatment is increased caloric intake.
The infant must be followed closely during this trial to evaluate response. The child may be seen again after 3-4 days if a neonate or two weeks if an older child.
If there is no catch-up growth within the first month, more in depth evaluation of the child will be needed.
- Berwick Donald, Levy, Janice, and Kleinerman,Ruth. Failure to Thrive: diagnositic yield of hospitalization. Archives of Disease of Childhood. 1982 57, 347-351
- Schwartz L. David. Failure to Thrive. Old Nemesis in the New Millenium Pediatrics in Review. August 2000
- Zanel Joseph. Failure to Thrive Pediatrics in Review. November 1997
- Mei Z et al. Shifts in Percentiles of Growth During Early Childhood: Analysis of Longitudinal Data from the California Child Health and Development Study Pediatrics June 2004 e617
- Gahagan, S. Failure to Thrive: A Consequence of Undernutrition. Pediatrics in Review 2006
- Jaffe,A. Failure to Thrive: Current Clinical Concepts. Pediatric in Review. March 2011
- Kerzner, Benny. "Understanding Pediatric Growth Failure." (2012).