Observed Station · Failure to Thrive · Data Interpretation
⏱️ TIME REMAINING
08:00
📋 Data Interpretation Station
Failure to Thrive – Clinical Scenarios with Lab & Imaging
You will be presented with 8 clinical scenarios of children with failure to thrive.
For each, interpret the clinical and diagnostic data and provide: 1) Diagnosis, 2) Any other test, 3) What to do next, 4) Follow-up plan.
Case 1
4-month-old, exclusively breastfed. Weight dropped from 50th to 5th percentile in 2 months. No vomiting, no diarrhea. Mother reports poor latch and short feeds.
Weight for length
90th percentile (normal)
Serum Albumin
3.6 g/dL (normal)
Hemoglobin
11.2 g/dL (normal)
Pre-feed weight (breast)
5.0 kg
Post-feed weight
5.1 kg (50 mL intake)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Failure to thrive due to inadequate intake (poor breastfeeding latch/ineffective feeding).
• Any other test: Lactation consult, pre/post-feed weights (done), assessment of milk supply (pumping), or supplementation trial.
• What to do next: Lactation support (positioning, latch), consider supplemental expressed breast milk or formula, monitor weight.
• Follow-up plan: Weight check in 1 week, reassess feeding, if poor weight gain, consider high-calorie formula supplementation.
Case 2
6-week-old, projectile vomiting after feeds, weight <3rd percentile. Palpable olive in epigastrium.
Serum Sodium
128 mEq/L (low)
Serum Potassium
2.8 mEq/L (low)
Serum Chloride
85 mEq/L (low)
ABG (pH)
7.52 (alkalosis)
Ultrasound abdomen
Thickened pylorus (4.5 mm)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Pyloric stenosis – projectile vomiting, olive mass, hypochloremic metabolic alkalosis, thickened pylorus on ultrasound.
• Any other test: Electrolytes (already done), ABG, renal function, pre-op assessment.
• What to do next: Correct dehydration and electrolyte imbalance (0.9% saline with potassium). Surgical referral for pyloromyotomy.
• Follow-up plan: Post-op feeding advancement, monitor weight gain, surgical wound care.
Case 3
8-month-old, chronic diarrhea, bulky foul-smelling stools, failure to thrive. Sweat chloride 72 mmol/L.
Sweat chloride
72 mmol/L (>60 diagnostic)
Fecal elastase
40 µg/g (low, normal >200)
Serum Vitamin E
2.0 mg/L (low, normal 5-20)
Chest X-ray
Hyperinflation, peribronchial thickening
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Cystic fibrosis (pancreatic insufficiency) – elevated sweat chloride, low fecal elastase, fat-soluble vitamin deficiency.
• Any other test: CFTR mutation analysis, chest X-ray (done), sputum culture, stool fat, liver function tests.
• What to do next: Start pancreatic enzyme replacement therapy (PERT) with meals. Fat-soluble vitamin supplementation (A, D, E, K). Nutritionist consult.
• Follow-up plan: Monitor weight, stool frequency, vitamin levels, respiratory symptoms. CF team (multidisciplinary).
Case 4
5-year-old, chronic diarrhoea, abdominal distension, iron deficiency. IgA anti-tTG >100 U/mL.
IgA anti-tTG
>100 U/mL (strongly positive)
Total IgA
Normal
Ferritin
8 ng/mL (low)
Duodenal biopsy
Villous atrophy (Marsh 3)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Celiac disease – positive anti-tTG, villous atrophy on biopsy, iron deficiency anaemia.
• Any other test: HLA DQ2/DQ8, bone density (if long-standing), thyroid antibodies (associated autoimmune).
• What to do next: Start strict gluten-free diet (GFD) with dietitian support. Iron supplementation.
• Follow-up plan: Monitor tTG titres (should decrease), growth, nutritional status. Screen for first-degree relatives.
✅ Model Answer:
• Diagnosis: Iron deficiency anaemia – microcytic, low ferritin, elevated TIBC, pica, koilonychia.
• Any other test: Stool for occult blood (rule out GI loss), lead level, celiac screen, dietary history.
• What to do next: Oral ferrous sulphate 3-6 mg/kg/day elemental iron. Limit cow's milk to <500 mL/day. Dietary advice.
• Follow-up plan: Check reticulocyte response in 1 week, Hb in 4 weeks. Continue iron for 3 months after Hb normalizes.
Case 6
2-year-old, bowing legs, widened wrists, hypocalcaemia, low 25-OH vitamin D.
25-OH Vitamin D
8 ng/mL (low, normal >30)
Serum Calcium
7.5 mg/dL (low)
Phosphorus
2.5 mg/dL (low)
ALP
650 U/L (elevated)
X-ray wrist
Widened growth plates, cupping, fraying
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Vitamin D deficiency rickets – low 25-OHD, hypocalcaemia, elevated ALP, rachitic X-ray changes.
• Any other test: PTH, calcium, phosphorus (done), serum magnesium, alkaline phosphatase (done), renal function, 1,25-OHD if needed.
• What to do next: Stoss therapy (150,000-300,000 IU vitamin D orally once) or high-dose daily vitamin D (2000-4000 IU/day). Calcium supplementation.
• Follow-up plan: Monitor calcium, ALP, 25-OHD in 3 months. Repeat X-ray in 6 months. Maintenance vitamin D 400 IU/day.
Case 7
6-month-old, FTT, tachypnoea, sweating with feeds. Echo shows VSD with left-to-right shunt.
BNP
450 pg/mL (elevated)
Chest X-ray
Cardiomegaly, pulmonary edema
Echocardiogram
Large VSD, left-to-right shunt, LV dilation
SpO2
98% (normal)
Feeding
Poor, takes 30 min/100 mL
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Congestive heart failure due to large VSD – tachypnoea, sweating, FTT, cardiomegaly, pulmonary edema.
• Any other test: ECG, cardiac catheterisation (if needed), renal/liver function, blood culture (if sepsis).
• What to do next: Start diuretics (furosemide), afterload reduction (ACE inhibitor), high-calorie feeds (NG if needed). Cardiology consult.
• Follow-up plan: Monitor weight, urine output, respiratory status. Plan for VSD closure (surgical or transcatheter) when stable/age-appropriate.
Case 8
7-year-old, short stature (height -3 SDS), delayed bone age, normal growth hormone stimulation test? (but low IGF-1)
Height SDS
-3.0 (short)
Weight SDS
-2.5 (low)
Bone Age
4 years (delayed)
IGF-1
25 ng/mL (low, normal 50-200)
GH stimulation test (peak)
3.5 ng/mL (low, normal >10)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Growth hormone deficiency (GHD) – short stature, delayed bone age, low IGF-1, poor GH response to stimulation.
• Any other test: MRI pituitary (look for structural abnormalities), thyroid function, cortisol, other pituitary hormones.
• What to do next: Start recombinant human GH (rhGH) therapy (0.025-0.05 mg/kg/day). Monitor for side effects.
• Follow-up plan: Monitor height velocity every 3-6 months, IGF-1 levels. Annual bone age. Adjust dose as needed.
⚠️ Key Concept: Approach to Failure to Thrive
• Inadequate intake: Breastfeeding difficulty, formula errors, neglect → lactation support, caloric increase.
• Malabsorption: Celiac, CF, PLE → specific tests (sweat test, anti-tTG, fecal α1-AT).
• Increased demand: CHD, chronic infection, hyperthyroidism → treat underlying.
• Endocrine: GH deficiency, hypothyroidism → hormone replacement.
• Red flags: Weight crossing >2 percentiles, weight <80% median, FTT with vomiting/diarrhea, failure to respond to nutritional intervention.
🎯 Examiner Scoring Checklist
• Identifies inadequate intake (breastfeeding difficulty, formula errors)