Failure to Thrive — Viva

Q1: Definition (2 min)

"How do you define failure to thrive?"

• Weight under 3rd centile (classic) OR crossing centile lines downward; AAP 2026 z-score criteria (weight-for-length/BMI < -1.65 z, or fall >= 1 z; under-2s velocity < -2 z)
• Velocity more important than single measurement
• NICE thresholds: fall across 1+ centile spaces (BW below 9th), 2+ (9th-91st), 3+ (above 91st), or weight below 2nd centile
• Head circumference preserved in non-organic FTT; in organic disease weight falls first, height later, head circumference last ^{[1] [2] [3]}

Q2: Causes (3 min)

"What are the causes of FTT?"

• Inadequate caloric intake is the single commonest cause — often psychosocial/caregiver-driven (non-organic)
• Organic: inadequate absorption (coeliac ~1.4% seroprevalence, 0.7% biopsy-confirmed; CF), increased requirements (CHD, chronic disease), increased losses (GERD, diarrhoea)
• Endocrine: hypothyroidism, GH deficiency (1 in 4000) ^{[5] [6] [4]}

Q3: Assessment (3 min)

"How do you assess a child with FTT?"

• Detailed feeding history (3-day diary)
• Growth chart (weight, height, head circumference + velocity)
• Social history (safeguarding screen)
• Targeted investigations: urine MC&S, FBC, ferritin, coeliac screen, TFTs, sweat test if indicated ^{[1] [3]}

Q4: Refeeding Syndrome (2 min)

"What is refeeding syndrome and how do you prevent it?"

• Occurs when feeding resumes after malnutrition
• Electrolyte shifts: hypophosphataemia, hypokalaemia, hypomagnesaemia
• Thiamine deficiency
• Fluid retention, cardiac arrhythmias
• Prevention: start low calories (F-75), correct electrolytes, thiamine, gradual increase ^[1]

References6ShowHide

1. [1]Goodwin ET, Buel KL, Cantrell LD. Growth Faltering and Failure to Thrive in Children. Am Fam Physician, 2023.PMID 37327159
2. [2]Kersten HB, Goday PS, Abdelhadi R, et al. Clinical Practice Guideline for Diagnosis and Management of Faltering Weight. Pediatrics, 2026.PMID 41833317
3. [3]National Institute for Health and Care Excellence. Faltering growth: recognition and management of faltering growth in children (NG75). NICE, 2017.Source
4. [4]Goh LH, How CH, Ng KH. Failure to thrive in babies and toddlers. Singapore Med J, 2016.PMID 27353148
5. [5]Murray PG, Dattani MT, Clayton PE. Controversies in the diagnosis and management of growth hormone deficiency in childhood and adolescence. Arch Dis Child, 2016.PMID 26153506
6. [6]Singh P, Arora A, Strand TA, et al. Global prevalence of celiac disease: systematic review and meta-analysis. Clin Gastroenterol Hepatol, 2018.PMID 29551598