What are the relevant investigations for a child presenting with failure to thrive (FTT)?

Relevant Investigations for Failure to Thrive (FTT)

A comprehensive evaluation for a child with failure to thrive should include thorough nutritional assessment, detailed history, physical examination, and targeted laboratory tests based on clinical findings rather than routine extensive testing. 1

Initial Assessment

Growth Parameter Evaluation

• Plot weight, length, and head circumference on appropriate growth charts
• Calculate weight-for-length ratio
• Determine rate of weight gain/loss
• Use WHO standards for children 0-2 years and CDC charts for children >2 years 1
• Document if weight is below 10th percentile, has crossed two or more major percentile lines downward, or weight-for-height is below 10th percentile 1

Detailed History

• Nutritional history:

  • Detailed 24-hour dietary recall
  • Feeding patterns and behaviors
  • Caloric intake calculation
  • Breastfeeding assessment (frequency, duration, technique)
  • Formula preparation (if applicable)
  • Introduction of solid foods
  • Food allergies or intolerances

• Medical history:

  • Birth history and prenatal factors
  • Previous growth measurements
  • Chronic illnesses
  • Recurrent infections
  • Vomiting or reflux
  • Stool patterns (diarrhea, constipation)
  • Developmental milestones

• Social history:

  • Family dynamics
  • Caregiver mental health
  • Economic resources
  • Food security
  • Home environment

Physical Examination

• Complete physical examination with special attention to:
  • Vital signs
  • Hydration status
  • Signs of systemic illness
  • Dysmorphic features suggesting genetic disorders
  • Neurological status
  • Evidence of neglect or abuse
  • Edema
  • Organomegaly

Laboratory and Diagnostic Evaluation

First-line Investigations

Laboratory testing should be targeted based on clinical findings rather than performed routinely, as most cases of FTT have non-organic causes 2

Consider the following based on history and physical examination:

• Complete blood count
• Basic metabolic panel
• Urinalysis
• Thyroid function tests (TSH, free T4)
• Celiac disease screening 1
• Lead level (in high-risk areas)

Additional Targeted Investigations

Based on specific clinical findings, consider:

1. Gastrointestinal concerns:

   • Liver function tests
   • Swallowing studies
   • pH studies for gastroesophageal reflux
   • Upper gastrointestinal series
   • Endoscopy (if indicated by gastroenterologist) 3
   • Alpha-1 antitrypsin levels (if liver dysfunction present) 3

2. Endocrine concerns:

   • Thyrotropin, free thyroxine
   • IGF-1 and IGF-BP3 levels
   • Growth hormone stimulation studies (directed by endocrinologist) 3

3. Genetic/syndromic concerns:

   • Chromosomal analysis
   • Specific genetic testing based on clinical features

4. Metabolic concerns:

   • Serum amino acids
   • Urine organic acids
   • Ammonia levels

5. Cardiac concerns:

   • Echocardiogram (if heart disease suspected)

6. Neurological concerns:

   • Brain imaging (if neurological abnormalities present)
   • EEG (if seizures suspected)

Special Considerations

When to Consider Hospitalization

• Failure of outpatient management
• Severe malnutrition (weight-for-height Z-score < -3) with medical instability 1
• Suspicion of abuse or neglect
• Severe psychosocial impairment of caregiver 4

Follow-up Monitoring

• Infants: every clinic visit
• Older children and adolescents: every 3 months
• Monitor weight gain (target 17-20 g/kg/day for catch-up growth) 1

Common Pitfalls to Avoid

1. Excessive laboratory testing: Most cases of FTT are non-organic and can be diagnosed through history and physical examination. Routine laboratory testing rarely identifies a cause and is not generally recommended 4, 2.

2. Missing psychosocial factors: The majority of FTT cases involve inadequate caloric intake due to behavioral or psychosocial issues 4.

3. Delayed intervention: Early intervention is essential to prevent long-term sequelae from nutritional deficiency 5.

4. Not using appropriate growth charts: Children with specific conditions (e.g., premature infants, genetic syndromes) require specialized growth charts 1.

5. Focusing only on weight: Comprehensive assessment should include weight, length/height, and head circumference measurements 1.

By following this structured approach to investigating failure to thrive, clinicians can efficiently identify underlying causes and implement appropriate interventions to improve outcomes for affected children.