Pediatrics · Year 3 · from Pediatrics
Case 1: Failure to Thrive - Inadequate Intake
Patient Demographics
- Age: 4-month-old female
- Sex: Female
Chief Complaint
"My baby isn't gaining enough weight."
History of Present Illness
A 4-month-old exclusively breastfed female is brought in by her first-time mother for a weight check. The infant's weight has plateaued over the past 6 weeks and has fallen from the 35th percentile at 2 months to below the 5th percentile. Mother reports the baby feeds frequently (every 1-2 hours) for about 5-10 minutes per breast but seems to tire easily and falls asleep at the breast. She has been supplementing with 1-2 oz of pumped breast milk after some feeds but is unsure if the baby is getting enough. The baby has 4-5 wet diapers and 2-3 small yellow stools daily (decreased from newborn period). Mother denies any vomiting, diarrhea, fever, or irritability. The infant was born at term with birth weight of 3.2 kg.
Growth Parameters
- Birth weight: 3.2 kg (35th percentile)
- Current weight: 4.6 kg (<5th percentile, weight-for-age z-score -2.1)
- Length: 60 cm (25th percentile)
- Head circumference: 40 cm (25th percentile)
- Weight-for-length: <5th percentile
- Expected weight at 4 months: ~6.0-6.5 kg
Physical Examination
- General: Thin-appearing infant, alert but quiet, decreased subcutaneous fat
- HEENT: Anterior fontanelle slightly sunken, mucous membranes moist
- Cardiovascular: Regular rate, no murmurs
- Respiratory: Clear, no distress
- Abdomen: Soft, non-tender, no organomegaly, loose skin folds
- Skin: Decreased subcutaneous tissue, especially over buttocks and thighs
- Neurologic: Appropriate tone, responsive, good eye contact, smiles
- Developmental: Age-appropriate (follows face, coos, holds head up)
Workup
- CBC: Normal
- CMP: Normal
- Urinalysis: Specific gravity 1.025 (concentrated), otherwise normal
- Pre/post feed weights: 15 g difference (inadequate milk transfer; expected 60-90 g)
- Maternal breast examination: Normal
Diagnosis
Failure to thrive due to inadequate caloric intake (breastfeeding difficulty with poor milk transfer)
Clinical Reasoning
This infant demonstrates classic failure to thrive with weight <5th percentile, weight crossing downward across percentile lines, and weight-for-length <5th percentile with relative preservation of length and head circumference (indicating caloric rather than chronic or endocrine etiology). The history of short feeding duration, fatigue at breast, and pre/post feed weights showing minimal transfer indicate breastfeeding difficulty. The normal developmental assessment and physical exam argue against underlying organic disease. This is "non-organic" FTT due to inadequate intake.
Management
- Immediate nutritional intervention:
- Increase caloric intake with formula supplementation after breastfeeds
- Target 150-180 kcal/kg/day initially (catch-up growth)
- Feeding goal: 24-32 oz total daily intake
- Breastfeeding support:
- Lactation consultant referral
- Evaluate latch, positioning, milk supply
- Consider galactagogues if supply issue confirmed
- Close monitoring:
- Weight check in 48-72 hours, then weekly until gaining appropriately
- Target weight gain: 20-30 g/day (catch-up growth)
- Maternal support:
- Screen for postpartum depression
- Provide encouragement and emotional support
- Consider further workup if no improvement: Sweat chloride, celiac panel, thyroid function
Clinical Image
Image Description: WHO growth chart demonstrating the pattern of falling weight percentiles characteristic of failure to thrive.
Source: World Health Organization URL: https://www.who.int/tools/child-growth-standards/standards/weight-for-age License: CC BY-NC-SA 3.0