Description

• Failure to thrive (FTT) is not a diagnosis but a sign of inadequate nutrition in young children manifested by a failure of physical growth, usually affecting weight. In severe cases, decreased length and/or head circumference may develop.
• Various parameters are used to define FTT:
  • Weight for age <5th percentile on >1 occasion
  • Weight that drops ≥2 major percentile lines on standard growth charts
  • Weight <80% median weight for length
  • Weight <75% median weight for age
  • Weight for length <5th percentile
  • Height for age <5th percentile
• Weight for length may be the simplest method to identify FTT, but verify with other parameters.

• Children with genetic syndromes, intrauterine growth restriction (IUGR), or prematurity follow different growth curves.
• 25% of children will decrease their weight or height crossing ≥2 major percentile lines in the first 2 years of life. These children are falling to their genetic potential or demonstrating constitutional growth delay (slow growth with a bone age < chronologic age). After shifting down, these infants grow at a normal rate along their new percentile and do not have FTT.

Epidemiology

• Predominant age: 6–12 months; 80% <18 months
• Predominant sex: Male = Female

• As many as 10% of children seen in primary care have signs of growth failure.
• 1–5% of pediatric inpatient admissions are for FTT.

Risk Factors

• Psychosocial risks:
  • Poverty, parent(s) with mental health disorder or cognitive impairment, poor parenting skills or hypervigilant parents, families with unique health/nutritional beliefs, physical or emotional abuse, substance abuse, and social isolation
• Medical risks:
  • Intrauterine exposures, history of IUGR (symmetric or asymmetric), congenital abnormalities, oromotor dysfunction, premature or sick newborn, infant with physical deformity, acute or chronic medical conditions, developmental delay

Pregnancy Considerations
FTT is linked to intrauterine exposures, IUGR, and prematurity.

Genetics
Multiple genetic disorders can cause FTT.

General Prevention

• Educate parents on normal feeding and parenting skills
• Access to supplemental feeding programs (WIC)

Pathophysiology

• Mismatch between caloric intake and caloric expenditure
• Often grouped into 4 major categories:
  • Inadequate caloric intake (most frequent)
  • Inadequate caloric absorption
  • Excessive caloric expenditure
  • Defective utilization

Etiology

• Traditionally, FTT was classified as organic or nonorganic, but most cases are a combination of these factors.
• FTT often begins with a specific event and may lead to persistent difficulties.
• Causes of FTT can be grouped by pathophysiology (including examples):
  • Inadequate intake: Breastfeeding difficulty, incorrect formula preparation, poor transition to food (6–12 months), poor feeding habits (e.g., excessive juice, restrictive diets), mechanical problems (e.g., oromotor dysfunction, congenital anomalies, GERD, CNS or PNS anomalies), oral aversion, poverty, neglect, poor parent–child interaction
  • Inadequate absorption: Necrotizing enterocolitis, short gut syndrome, biliary atresia, liver disease, cystic fibrosis, celiac disease, milk protein allergy, vitamin/mineral deficiency
  • Increased expenditure: Hyperthyroidism, congenital/chronic cardiopulmonary disease, HIV, immunodeficiencies, malignancy, renal disease
  • Defective utilization: Metabolic disorders, congenital infections (TORCH)