Reasoning GP · Algorithm · 1-page summary
Abdominal pain in children
For: children aged 0–12 years with acute or recurrent abdominal pain in primary care, including post-menarchal girls. Not for: detailed management of constipation, UTI or surgical problems (use those pages).
Core rule: exclude the surgical abdomen first — examine the testes in every boy, ask "is your child eating?", and never delay suspected appendicitis, torsion or intussusception for primary-care tests. Normal bloods do not exclude early appendicitis.
0Stop — call 999 now — or emergency transfer
- Shock, severe systemic illness, reduced consciousness; peritonism with instability or suspected perforation; severe obstruction, volvulus or intussusception; suspected testicular or ovarian torsion; suspected DKA with significant illness; ectopic with haemodynamic compromise; severe trauma → 999
- While waiting: do not withhold analgesia — it improves examination, but reassess after. Do not delay transfer for ultrasound or other primary-care tests. Concerning bruising or suspected non-accidental injury → activate safeguarding as well.
1Triage by age — commonest serious causes
| Age | Think of → action |
|---|---|
| Under 3 months | Serious cause not confidently excluded → Same-day paediatrics; suspected UTI → Immediate paediatrics |
| 3 months–5yr | Intussusception (peak 6–18mo), hernia, UTI, constipation. <5yr with significant pain → Same-day surgical |
| 5–12 years | Appendicitis (peak 10–12yr), functional pain, constipation, IBD, coeliac |
| Post-menarchal | Offer a confidential pregnancy test; consider ovarian torsion, cyst and PID. |
2Screen — one row is enough
- Green (bilious) vomiting or intussusception (colicky pain, pallor, drawing up legs, redcurrant-jelly stool) → Immediate surgical / ED, even if stable
- Appendicitis: persistent or worsening localised pain, anorexia, fever, pain on movement → Same-day surgical
- Testicular pain or a high, horizontal testis → Immediate surgical / urology; no ultrasound first
- Vomiting + pain + polyuria/polydipsia → capillary glucose and ketones now; suspected DKA → Emergency; raised glucose alone → Same-day diabetes team
- Irreducible hernia, bloody diarrhoea, uncontrolled pain, significant dehydration → Same-day. Positive pregnancy test + pain, bleeding or syncope → Immediate gynae
- Purpura + pain = HSP; severe pain, GI bleeding, scrotal involvement or hypertension → Same-day paeds
3Assess
☐ Behaviour (still = peritonism), hydration, pallor ☐ Abdomen, hernial orifices, scrotum in every boy, skin, joints ☐ Urine dipstick if UTI plausible ☐ Glucose + ketones if indicated ☐ Growth in recurrent pain. Not in primary care: X-ray or ultrasound, routine rectal examination, routine H. pylori testing.
4Classify — only if the screen is negative
- Constipation — hard infrequent stools, withholding, soiling, faecal mass; not if distension with vomiting or faltering growth.
- Mesenteric adenitis — viral illness, no peritonism; only after surgical causes are considered.
- Functional abdominal pain — Rome IV: at least 4 times per month for at least 2 months, no alarm features after structured assessment and growth review.
- Coeliac / IBD — faltering growth, iron deficiency, diarrhoea, weight loss, perianal disease → tTG IgA + total IgA (on gluten); calprotectin only in the local pathway.
- Uncertain — cannot exclude a surgical cause → Same-day paeds / ED.
5Treat today — doses: NICE/SPC, BNFC, local formulary
- Analgesia: paracetamol ± ibuprofen (aged 3 months+), weight-based. No ibuprofen with significant dehydration, renal disease, GI bleeding or NSAID-sensitive asthma.
- Constipation: treat impaction first, then maintenance; macrogol 3350 with electrolytes, age-specific dosing.
- Functional pain: positive explanation, normal activity and school; CBT or gut-directed hypnotherapy can be considered.
- Persistent typical heartburn or epigastric pain: consider a 4-week PPI trial (NG1); not for nonspecific pain.
6Refer and follow up
- Urgent paeds outpatient: suspected IBD, positive coeliac serology, weight loss or jaundice with pain, recurrent pain >1 month not responding.
- HSP: urinalysis and BP over 6 months; agree who does it.
- Functional pain: review in 4–6 weeks with growth. Significant anxiety → CAMHS.
7Never reassure by
- Normal FBC, CRP or a low appendicitis score.
- No classic migration to the right iliac fossa — atypical is common, especially under 5.
- Pyuria — appendicitis can cause it.
- No testicular symptoms — torsion can present as abdominal pain.
- A normal calprotectin when clinical concern is strong.
- Pain eased by analgesia — re-examine.
8Safety-net — say it, then document it
999 “Call 999 if the pain suddenly gets much worse and your child is very unwell, becomes floppy or pale, the tummy goes hard, breathing is very difficult, a rash does not fade under a glass, or they are drowsy with deep, fast breathing. Green vomit or sudden pain or swelling in a testicle: go to A&E straight away even if your child seems well.” Same day “If the pain is getting worse or moving to one place, or your child stops eating, becomes feverish or more unwell, develops urinary symptoms, blood in the poo, or extra thirst and weeing, go straight to A&E — do not wait for a GP appointment.”
Review within 24 hours if amber features or uncertainty; earlier if deteriorating. A parent who remains concerned → reassess carefully, do not just reassure.
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Site of maximal tenderness, guarding and genital examination recorded
Urine, glucose/ketones and pregnancy test done where indicated
Positive diagnosis made, or uncertainty stated with review within 24 hours
Safety-net given; safeguarding considered
Summary of the full Reasoning GP abdominal pain in children algorithm, which holds the history, examination, investigations and evidence. Sources: NICE CG99, NG224, NG1, NG20, NG143, NG12 (updated April 2026); UK Kidney Association IgA vasculitis guidance; Rome IV. Clinical reference — follow local paediatric pathways and check doses in the current BNFC.