Diagnosis: Organic Failure to Thrive
This 10-month-old infant has organic failure to thrive (FTT), evidenced by the combination of irritability during feeding, multiple vomiting episodes, and isolated weight faltering (below 3rd percentile) while height and head circumference remain normal (25th percentile). 1
Key Diagnostic Features
Growth Pattern Analysis
The critical distinguishing feature here is the disproportionate growth pattern:
- Weight <3rd percentile with height and head circumference at 25th percentile indicates acute malnutrition affecting weight first 1
- This pattern strongly suggests an organic etiology rather than nonorganic causes, which typically show proportionate growth failure across all parameters 2
- Normal birth history with two healthy siblings makes chromosomal abnormalities unlikely 3
Clinical Presentation Supporting Organic Etiology
Irritability during feeding combined with multiple vomiting episodes points to a specific organic pathology rather than psychosocial deprivation 1, 4:
- These symptoms suggest gastroesophageal reflux disease (GERD), feeding/swallowing dysfunction, or other gastrointestinal pathology 3
- Nonorganic FTT typically presents with decreased intake due to psychosocial factors without prominent GI symptoms like vomiting 5, 6
- The presence of active symptoms (irritability, vomiting) during feeding is a red flag for organic disease 2
Distinguishing Organic from Nonorganic FTT
Why This is NOT Nonorganic FTT:
Nonorganic FTT characteristics that are ABSENT here 5, 6:
- No evidence of psychosocial deprivation (two healthy siblings suggest adequate caregiving environment)
- Presence of specific GI symptoms (vomiting, feeding irritability) rather than simple decreased intake
- Disproportionate growth failure (weight only) rather than global growth delay
- Acute presentation with active symptoms rather than chronic neglect pattern
Why This is NOT Normal Development:
- Weight below 3rd percentile represents pathologic growth failure, not normal variation 1
- Active symptoms (vomiting, feeding irritability) are never normal 1
Why This is NOT Chromosomal Abnormality:
- Normal head circumference (25th percentile) argues strongly against chromosomal disorders 3
- Chromosomal abnormalities typically present with microcephaly, dysmorphic features, and proportionate growth failure across all parameters 3
- Two healthy siblings make inherited genetic conditions less likely 3
Clinical Approach
Immediate evaluation should focus on identifying the organic cause 1:
- Gastroenterology referral for evaluation of GERD, swallowing dysfunction, or other GI pathology given the vomiting and feeding irritability 3, 1
- Upper GI series and/or pH probe studies to document reflux 4
- Swallowing study if aspiration or dysphagia suspected 3, 1
- Basic laboratory screening (CBC, comprehensive metabolic panel, thyroid function) to exclude systemic disease 1
Answer: C - Organic failure to thrive