🍼 Chapter 9: Failure to Thrive (FTT)

Nelson's Pediatric Symptom-Based Diagnosis | Growth Faltering · Caloric Insufficiency · Organic vs Nonorganic · Wasting vs Stunting · Catch-up Growth

🔍 Failure to Thrive (Growth Faltering): Key Concepts

📊 Definition of FTT
Weight <3rd percentile on WHO charts; weight-for-length <5th percentile; crossing ≥2 major percentiles downward in <6 months; or growth velocity below normal for age. Weight affected first, then length, then head circumference.
🔄 Energy Balance Equation
E(in) = E(out) + E(growth) + E(stored). FTT occurs when intake insufficient to meet needs for growth, or when losses/requirements are increased.
⚠️ Organic vs Nonorganic
Often mixed etiology. Nonorganic: psychosocial, poverty, dysfunctional feeding, maternal depression, neglect. Organic: GI (GER, celiac), CF, cardiac, renal, endocrine (hypothyroidism, GH deficiency), metabolic, chronic infection.
💧 Wasting vs Stunting
Wasting: weight-for-length < -2 z-scores (acute malnutrition). Stunting: length-for-age < -2 z-scores (chronic malnutrition). Wasting affects weight first; stunting indicates prolonged deficiency.
🧬 Three Growth Patterns (Type I, II, III)
Type I: ↓weight, nl/nl length & HC → malnutrition. Type II: ↓weight & length, nl HC → endocrinopathy, constitutional delay. Type III: ↓all 3 → chromosomal, metabolic, IUGR, severe malnutrition.
🚩 Red Flags & Management
Red flags: microcephaly, dysmorphism, hepatomegaly, developmental delay, recurrent vomiting, failure of catch-up. Management: detailed diet history, social work, nutritionist, mealtime observation, hospitalization if severe (<70% weight/length).

💡 Key Takeaway: FTT is a sign, not a diagnosis. A thorough history (feeding, psychosocial, medical) is the best diagnostic tool. Plot growth curves, calculate weight-for-length. Most cases are nonorganic or mixed. Organic causes often have additional clues on H&P. Caloric needs for catch-up: 120-180 kcal/kg/day.

🩺 Clinical Approach to Failure to Thrive: Step-by-Step Algorithm

🔹 Step 1: Confirm abnormal growth pattern
• Plot weight, length/height, and head circumference on WHO (0-24mo) or CDC (>24mo) growth charts.
• Calculate weight-for-length or BMI.
• Look for crossing of percentiles, weight <3rd percentile, or weight-for-length <5th percentile.
🔹 Step 2: Differentiate pattern (Type I, II, III)
• Type I (weight ↓, length nl, HC nl) → caloric insufficiency (most common).
• Type II (weight ↓, length ↓, HC nl) → endocrinopathy, constitutional delay, skeletal dysplasia.
• Type III (all ↓) → congenital, chromosomal, metabolic, severe malnutrition.
🔹 Step 3: Thorough history (most important)
• 24-hour diet recall or 3-day food diary.
• Feeding dynamics: parent-child interaction, mealtime duration, distractions (TV), self-feeding.
• Psychosocial: maternal depression, food insecurity, substance abuse, child neglect.
• Review of systems: vomiting, diarrhea, constipation, tachypnea, cyanosis, recurrent infections.
🔹 Step 4: Physical exam & red flags
• Dysmorphic features (genetic syndrome), hepatosplenomegaly (storage, CF), clubbing (CF, cardiac), rash (acrodermatitis enteropathica), neurologic deficits.
• Assess hydration, muscle wasting, subcutaneous fat.
🔹 Step 5: Targeted labs & management
• Screening: CBC, ESR, CRP, electrolytes, BUN, creatinine, albumin, UA, urine culture.
• Specific: celiac panel (TTG IgA), sweat test (CF), lead level, TSH, HIV if indicated.
• Management: Increase caloric density (add oil, formula concentrate), involve nutritionist, social work, consider hospitalization if severe (<70% weight/length) or concern for neglect.