Failure to thrive: organic vs non-organic causes and investigation
RezzyFailure to thrive—or faltering growth, as we often call it here in the UK—is a common but sometimes tricky topic. It basically describes a situation where a child's weight or rate of weight gain is significantly lower than expected for their age and sex.
When we're looking at the "why," we usually split it into organic (a physical medical condition) and non-organic (psychosocial or environmental factors) causes. In practice, though, it's often a bit of both!
Let me pull up a comparison to help you distinguish between the two.
| Feature | Organic Causes (Medical) | Non-Organic Causes (Psychosocial) |
|---|---|---|
| Definition | Growth failure due to an underlying medical condition. | Growth failure due to environmental or psychosocial factors. |
| Frequency | Less common (~5-10% of cases). | Much more common (~90% of cases). |
| Key Examples | Coeliac disease, Cystic Fibrosis, GORD, IBD, Congenital heart disease, Chronic kidney disease. | Inadequate food intake, poor feeding technique, neglect, poverty, or maternal depression. |
| History | Often has specific symptoms (e.g., chronic diarrhoea, cough, vomiting). | May have history of social stressors or disrupted feeding routines. |
| Examination | May show signs of systemic disease (e.g., heart murmur, abdominal distension). | May show signs of neglect or delayed developmental milestones. |
As you can see, the vast majority of cases are non-organic, often related to feeding difficulties or social factors. However, for the AKT, you need to know when to suspect an underlying medical issue and how to investigate it.
Investigation Approach
The most important "investigation" is actually a thorough history and physical examination, including a detailed feeding history and plotting growth on a centile chart.
If an organic cause is suspected, we usually start with a "screening" battery of tests:
- FBC and ESR/CRP: To look for anaemia or chronic inflammation.
- U&Es and Creatinine: To check renal function.
- Coeliac Screen: (Anti-TTG antibodies) — this is a classic exam answer for FTT!
- Urinalysis and Culture: To rule out a silent UTI.
- Stool Microscopy/Culture: If there's diarrhoea or malabsorption suspected.
- Thyroid Function Tests (TFTs): To rule out hypothyroidism.
I'll find some detailed lessons and a visual aid to help you visualize the diagnostic pathway.
📚 Faltering Growth Lessons
Setting up chat...