Reasoning GP · Algorithm · 1-page summary
Faltered growth in children
For: infants and children with weight faltering or poor weight gain in UK primary care (main focus 0–5 years), seen with a parent or carer. Not for: an acutely unwell child (block 0 first) or isolated short stature with normal weight gain (paediatric referral per BSPED standards).
Core rule: one low weight is not faltered growth — confirm a sustained fall across centiles on serial, accurate plots. Most faltering is about intake, but screen every child for organic red flags, an abdominal mass and safeguarding before reassuring.
0Stop — call 999 now — before measuring or a feeding history
- Shock, severe dehydration, drowsy, not responding or altered consciousness → 999. Other acute weight loss with lethargy, sunken fontanelle or reduced urine output → Same-day ED
- Bilious (green) vomiting (malrotation, obstruction), severe respiratory distress, suspected sepsis, hypoglycaemia or unable to maintain intake → 999 / same-day admission
- Severe acute malnutrition with clinical compromise → 999 / same-day admission
- Child in immediate danger → police 999 and/or Children's Social Care now
1Is it faltering? — serial plots, UK-WHO 0–4 y, UK90 4 y+ (NICE NG75)
| Birthweight centile | <9th | 9th–91st | >91st |
|---|---|---|---|
| Weight fall | ≥1 space | ≥2 spaces | ≥3 spaces |
Or current weight <2nd centile. Early days: loss >10% of birthweight or not back to it by 3 weeks → Same-day assessment; a trained person observes a feed.
Over 2 y: BMI <0.4th centile = probable undernutrition. Height >2 spaces below mid-parental centile → discuss with paediatrics.
2Screen — one row is enough
- Unwell with rapid weight loss or severe undernutrition; significant dehydration; persistent vomiting; murmur, organomegaly, regression, neuro signs → Same-day paediatrics
- Unexplained petechiae or hepatosplenomegaly → Immediate specialist assessment
- Abdominal mass, or unexplained organ enlargement or visible haematuria → consider Very urgent referral ≤48 h
- Pallor, fatigue, unexplained fever, persistent infection, generalised nodes, bone pain, bruising, bleeding → FBC ≤48 h; unwell with several → Same-day call acute paediatrics, no FBC wait
- Projectile vomiting, first 2 months → Same-day. Recurrent severe or unusual infections → Urgent; same-day if unwell
- Safeguarding: inadequate food provision, repeated non-attendance, inconsistent history, unexplained injury → safeguarding lead; suspected maltreatment → Children's Social Care
3Assess — feeding first, then examine fully
☐ Calibrated scales; weight with length/height; Red Book trend ☐ Head circumference in infants ☐ Feeding history incl. formula making; food security ☐ Full exam incl. abdomen, heart, dysmorphism, bruising
Tests: think UTI (urine, NG224) and coeliac serology (total IgA + IgA tTG; only after gluten in >1 meal daily for ≥6 weeks). Not in a well child: broad blood panels, bone age, growth hormone tests, vitamin D level for faltering alone.
4Classify — only if the screen is negative
- Inadequate intake (commonest) — breastfeeding or latch problems, over-diluted formula, mealtime battles → feeding support (block 5).
- Coeliac / malabsorption — loose, offensive stools, distension after gluten → serology; positive → paediatric gastroenterology. No gluten-free diet before confirmation.
- Cystic fibrosis — recurrent chest infections → check the bloodspot result; refer to the CF team.
- ARFID — extreme selectivity, sensory aversion → CAMHS and dietetics.
- Psychosocial — food insecurity, parental mental health, poverty: support, not proof of neglect; consider safeguarding in context.
- Uncertain — say so; discuss with paediatrics and set who reviews and when.
5Treat today — only these
- Breastfed: infant-feeding support (latch, milk transfer). If formula is added, keep breastfeeding and give expressed milk first.
- Formula: make exactly per the manufacturer — never concentrate or dilute. No energy-dense formula started in primary care.
- Older child: food-first fortification (butter, cheese, cream); 3 meals + 2–3 snacks; no pressure, no screens. Oral supplements: consider only after food-first, preferably with dietetic input.
- Ask about money for food: Healthy Start (free vitamins), food bank, benefits check.
6Refer and review routinely
- Paediatrics (NG75): no response to primary care intervention, slow linear growth or unexplained short stature, suspected coeliac, CF or IBD, dysmorphism or developmental concern.
- Health visitor (feeding observation, home visits) and paediatric dietitian; SLT for swallowing; parental depression → NHS Talking Therapies or perinatal mental health.
- Weigh no more often than daily <1 month, weekly 1–6 months, fortnightly 6–12 months, monthly from 1 year; length/height ≤3-monthly.
7Never reassure by
- One weight, or a plot without checking measurement technique.
- An alert, well child — still feel the abdomen for a mass.
- Missed appointments filed as "did not attend" — a safeguarding finding.
- A "reflux" label for persistent vomiting with poor weight gain.
- Negative coeliac serology without gluten in the diet or total IgA.
- Weight starting to improve — continue until the trajectory is stable.
8Safety-net — say it, then document it
999 “Call 999 if your child is very drowsy or not responding, shows signs of dehydration or shock, has green vomit, or is in danger.” Same day “Contact us today if your child suddenly stops feeding or refuses all food, loses weight quickly, gets a fever, vomiting or diarrhoea, or if you feel you can't cope.”
Document: what to watch for, when to come back and who to call — not "return if worse"; record safeguarding concerns at the time (date, time, what was seen and said, who was present).
✓Safe to manage in primary care only if — all five, documented
No block 0–2 row applies
Fall confirmed on serial, accurate plots
Full exam incl. abdomen; safeguarding considered
Goals, review interval, owner and escalation set; HV/dietitian involved
Safety-net given and documented
Summary of the full Reasoning GP faltered growth algorithm, which holds measurement technique, history, examination, feeding detail and evidence. Sources: NICE NG75, NG12 (updated April 2026), NG20, NG224, NG76, CG89, NG247; RCPCH UK-WHO charts; BSPED; Working Together to Safeguard Children 2026. Clinical reference — follow local paediatric and safeguarding pathways and check products and doses in the current BNF for Children.