What is the initial workup for a child with failure to thrive (FTT)?

Initial Workup for Failure to Thrive in Children

The initial diagnostic workup for a child with failure to thrive should include a detailed history, comprehensive physical examination, and targeted laboratory testing to identify potential organic and non-organic causes, with specialized evaluations reserved for cases with concerning findings or those who fail to respond to initial interventions. 1

History and Physical Examination

• Obtain detailed prenatal and birth history, including polyhydramnios, prematurity, and birth weight/length to identify potential risk factors 1
• Document growth trajectory using standardized growth charts (WHO charts for children <2 years, CDC charts for children ≥2 years) to assess weight, height, and head circumference 1, 2
• Evaluate feeding history, including difficulties with feeding, swallowing issues, vomiting, or gastroesophageal reflux 1
• Assess family history of growth disorders, genetic conditions, or metabolic diseases 1
• Examine for muscle wasting, decreased subcutaneous fat, and hair, skin, and nail changes suggesting nutritional deficiencies 1
• Evaluate for oral-motor dysfunction that may cause inadequate caloric intake 1
• Screen for potential psychosocial factors, including parent-child interactions and economic or emotional deprivation 3, 4

Initial Laboratory Testing

• Complete blood count to assess for anemia, infection, or hematologic disorders 1
• Comprehensive metabolic panel, including serum electrolytes, renal function tests, and liver function tests 1
• Thyroid function tests (TSH, free T4) to evaluate for hypothyroidism 1, 5
• Urinalysis to assess for signs of renal tubular disorders 1

When to Consider Additional Testing

• Reserve extensive diagnostic testing for children who have:

  • Severe malnutrition 2
  • Symptoms concerning for high-risk conditions 2
  • Failure to respond to initial nutritional interventions 6, 2
  • Clear symptoms of organic disease 6

• Consider specialized evaluations when initial assessment suggests specific etiologies:

  • Gastrointestinal evaluation for persistent feeding difficulties, reflux, or poor growth 1
  • Genetic evaluation, including chromosomal microarray or specific gene panels, for children with suspected genetic disorders 1
  • Metabolic workup when history suggests inborn errors of metabolism (e.g., recurrent vomiting, lethargy, developmental regression) 7
  • Endocrine evaluation for growth hormone deficiency if growth pattern suggests endocrine disorder 5

Important Considerations

• Routine extensive laboratory testing, imaging studies, and endoscopy yield an organic etiology in <1.4% of cases when not guided by specific clinical findings 6
• Most cases of failure to thrive result from inadequate caloric intake rather than organic disease 6, 2
• Consider screening for eating disorders (e.g., avoidant/restrictive food intake disorder) in older children 2
• Notify child protective services when evaluation leads to suspicion of abuse or neglect 4
• Regular follow-up to monitor growth response to interventions is critical 1

Potential Pitfalls

• Overreliance on laboratory testing without thorough history and physical examination may lead to unnecessary investigations 6
• Failure to recognize and treat growth faltering in the first two years of life may result in decreased adult height and cognitive potential 2
• Missing non-organic causes of failure to thrive, which are more common than organic etiologies 6, 2
• Overlooking psychosocial factors that may contribute to poor growth 3, 4