Clinical Inquiries

What is the clinical workup for failure to thrive?

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EVIDENCE-BASED ANSWER

The clinical evaluation of failure to thrive (FTT) includes a thorough history and physical examination; observation of parent–child interactions; observation and documentation of the child’s feeding patterns; and a home visit by an appropriately trained health care professional (Strength of Recommendation [SOR]: C). Further diagnostic testing should be performed as indicated by positive findings from the history and physical exam or if the child’s weight has not improved at follow-up (SOR: C).

Clinical commentary

A complex problem that requires a team approach
Robert Gauer, MD
Family Medicine Residency Clinic Faculty, Womack Army Medical Center, Fort Bragg, NC

We admit several infants with FTT to the hospital each month from a large population of young families at Fort Bragg, NC, and manage many more in our outpatient practice. Our experience confirms that FTT is a complex problem with many potential causes.

Laboratory and other evaluation beyond history, physical examination, and observation rarely help establish the diagnosis or prognosis. Incidental abnormalities occasionally change management, but more often result in false positives.

Close follow-up and a multidisciplinary team approach generally uncover the cause and lead to successful treatment. Children who don’t respond to treatment or have a suspected “organic” cause of FTT always warrant further laboratory investigation to identify the 1% of cases that result from a diagnosable disease. FTT can also be the sole indication of neglect or nonaccidental trauma, with devastating consequences.

Early identification of an infant or child approaching the diagnostic criteria for FTT is critical. Diagnosis and intervention may be delayed by inaccurate growth curve points, loss of a growth chart in a busy practice, or lack of well-child visits. Our experience with early detection and a multidisciplinary team treatment approach has been highly successful.

Evidence summary

FTT is a generic term used to describe a child whose current weight (or trajectory of weight gain) does not equal that of other children of similar age, gender, and ethnicity. No single accepted anthropometric measure can be used to diagnose the condition.1

FTT has been variously defined in children who:

  • drop more than 2 standard percentile lines on standardized growth charts,2
  • are below the third percentile for weight,
  • have weight-for-length <80% of ideal weight,3
  • have height-for-weight less than the third percentile,4
  • have weight-for-height less than the 10th percentile, or have weight-for-age less than 2 standard deviations below the mean for age.

Recent updates of standardized growth charts for children are available from the Centers for Disease Control and Prevention at www.cdc.gov/nchs/about/major/nhanes/growthcharts/clinical_charts.htm.

A complex diagnosis

FTT occurs when nutritive intake is insufficient to meet demands for growth (TABLE). It is usually manifested by failure to gain weight. In more severe cases, height and head circumference are affected. FTT is also associated with lower developmental testing scores,5 persistent poor growth, increased susceptibility to infections, and an increased prevalence of behavioral disorders and neurologic disability.4 As many as 10% of children seen in primary-care settings show signs of FTT.2

Children with FTT are most often identified when parents raise concerns about the child’s feeding or growth patterns or when a physician notes a decrease in the child’s growth on physical examination. The terms “organic” and “inorganic” or “nonorganic” FTT, often used to guide diagnostic thinking, are outdated because most cases of FTT are influenced by many variables.6 FTT represents the final common pathway of disruptions in the complex system of biological, psychosocial, and environmental factors contributing to a child’s growth and development.

TABLE
Failure to thrive: Causes and physical findings

GENERIC CAUSEASSOCIATED CONDITIONSPHYSICAL FINDINGS*DIAGNOSTIC EVALUATION
Inadequate caloric intakePoor food intake
  Chronic illness
  Inappropriate type/volume of feeding
Food not available
  Parental withholding
  Neglect
  Poverty
Signs of neglect or abuse
Minimal subcutaneous fat
Protuberant abdomen
Complete dietary history and psychosocial evaluation
Complete blood count (CBC)
Basic metabolic profile
Lead screening
Inadequate caloric absorptionGastrointestinal causes
  Malabsorption
  Chronic vomiting
  Pancreatic insufficiency
  Celiac disease
  Chronic reflux
  Inflammatory bowel
  disease
  Chronic renal disease
Cystic fibrosis
Dysmorphism suggestive of chronic disease
Organomegaly
Skin/mucosal changes
Stool pathogens
Stool fat
Cystic fibrosis screening
CBC/erythrocyte sedimentation rate (ESR)
Basic metabolic profile
Urinalysis (U/A)
Excessive caloric expenditureHyperthyroidism
Chronic disease (cardiac, renal, endocrine, hepatic)
Malignancy
Dysmporphism
Skin dysmorphology
Cardiac findings
TSH
CBC/ESR
Basic metabolic profile
Liver function tests
*Abnormal weight is observed in all cases.
Modified from Skuse DH et al., .8 Bergman P et al., .13 Krugman SD et al.14

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