Reasoning GP · Algorithm · 1-page summary
Vomiting in children
For: children aged 0–12 years with vomiting in primary care; NICE CG84 dehydration advice applies to under 5s, so use judgement and local paediatric pathways from age 5. Not for: adults (nausea and vomiting in adults) or detailed management of infant reflux, UTI, surgical problems or DKA (use those pages).
Core rule: classify hydration and exclude the dangerous causes — green vomit, raised intracranial pressure, DKA, pyloric stenosis — before calling it gastroenteritis. Never diagnose gastroenteritis from vomiting alone.
0Stop — call 999 now — emergency transfer
- Shock (reduced consciousness, pale or mottled cold skin, weak pulses, markedly prolonged CRT, hypotension), airway or breathing compromise, seizure, suspected meningitis or encephalitis (headache, photophobia, non-blanching rash) → 999
- Green vomit with instability or severe abdominal signs; suspected volvulus, obstruction, intussusception or peritonitis; significant haematemesis; suspected DKA → 999
- Vomiting + urticarial rash (anaphylaxis) → 999 + IM adrenaline immediately. Serious poisoning → 999; clinicians use TOXBASE or NPIS.
- While waiting: fluids per the local paediatric resuscitation pathway. Do not delay transfer for an abdominal X-ray, bloods or to confirm DKA.
1Triage by hydration — NICE CG84, no % estimate
| Category | Features → action |
|---|---|
| No clinical dehydration | Alert, normal urine output, moist mucosa, normal pulses → home: breast or formula feeds and usual fluids; ORS if at increased risk |
| Clinical dehydration | Reduced responsiveness, less urine, dry mucosa, tachycardia, tachypnoea, sunken eyes, prolonged CRT → ORS with reassessment; not tolerating ORS → Same-day ED |
| Shock | 999 — emergency transfer |
Signs are imperfect: interpret together, and if uncertain manage as the more severe category.
2Screen — one row is enough
- Green vomit in a well-appearing child, or uncertain yellow-green → Immediate paediatric / surgical
- Progressive or projectile vomiting in a hungry infant, especially under 2 months (pyloric stenosis) → Same-day specialist
- Raised ICP: morning or progressive headache, reduced consciousness, abnormal pupils, focal signs, bulging fontanelle → 999
- Polyuria, polydipsia, weight loss, hyperventilation, or known diabetes (normal glucose does not exclude DKA) → glucose; >11 mmol/L with symptoms → Immediate hospital
- Under 3 months with persistent vomiting, fever, poor feeding, dehydration or abnormal examination → Same-day ED; suspected UTI → Immediate paediatrics
- Haematemesis → Same-day hospital. Severe abdominal pain → 999 or Same-day surgical
3Assess
☐ ABCDE, weight, heart rate for age, CRT, mucosa, fontanelle ☐ Abdomen, herniae, testes where indicated ☐ Neurology and rash ☐ Ears and throat ☐ Urine only if UTI plausible ☐ Capillary glucose if diabetic symptoms, systemic illness, dehydration or uncertainty. Not in primary care: abdominal X-ray, routine bloods, routine stool culture (send if blood or mucus, suspected septicaemia or immunocompromised).
4Classify — only if the screen is negative
- Gastroenteritis — sudden vomiting and/or sudden loose stools; consider alternatives if vomiting is the only symptom.
- Infection elsewhere — UTI, otitis media, tonsillitis; fever under 5 → use NICE NG143.
- Reflux — effortless regurgitation in a thriving infant → reassure. Marked distress → feeding review (NG1).
- Cyclical vomiting — stereotyped episodes, well between, family migraine → paediatric outpatients.
- Uncertain — say so; review within 24 hours. Under 3 months → Same-day ED.
5Treat today — doses: NICE/SPC, BNFC, local formulary
- Clinical dehydration: low-osmolarity ORS 50 mL/kg over 4 hours plus maintenance, 5–10 mL every 1–2 min by syringe. Continue breastfeeding; no juice or fizzy drinks; normal diet after rehydration.
- No routine antiemetic: ondansetron via specialist pathway only; metoclopramide contraindicated under 1 year; domperidone not routine. No loperamide.
- Reflux: no acid suppression for posseting; consider a 4-week PPI or H2RA only with feeding difficulty, distress or faltering growth. Sleep flat on the back.
- Bloody diarrhoea (possible STEC): stool culture, no antimotility agents, warn about HUS (pallor, less urine, bruising).
6Refer and follow up
- Same-day paeds: unexplained faltering growth with vomiting, suspected metabolic disorder, failed ORS trial in surgery.
- Paeds outpatient: unexplained or stereotyped recurrent vomiting, suspected food allergy, reflux not settling after a 4-week PPI or H2RA trial.
- Exclusion from nursery or school until 48 hours after the last episode; check rotavirus vaccination; notify UKHSA for suspected food poisoning.
7Never reassure by
- A normal BP — it is a late sign of dehydration.
- A normal glucose in a child with known diabetes.
- Calling it feeding trouble when a baby vomits green.
- No palpable "olive" in a hungry, projectile-vomiting infant.
- Absent papilloedema — it does not exclude raised ICP.
- One reassuring hydration sign — interpret them together.
8Safety-net — say it, give it in writing, document it
999 “Call 999 if your child becomes floppy or unresponsive, collapses, has a fit, struggles to breathe, turns very pale with cold mottled skin, vomits large amounts of blood, or has a rash that does not fade.” A&E now “Green or yellow-green vomit even if your child seems well, blood or coffee-ground vomit, or extreme thirst, weeing a lot or fast deep breathing.”
Same day “Contact your GP or NHS 111 the same day for blood in the poo, worsening tummy pain or swelling, increasing drowsiness, fewer wet nappies, not keeping fluids down, forceful vomiting in a hungry baby, vomiting over 2 days or diarrhoea over 7 days, or if you feel your child is getting worse.”
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Hydration category, weight and heart rate recorded
Vomit colour asked; urine and glucose checked where indicated
Cause named, or uncertainty stated with review within 24 hours
Written safety-net and exclusion advice given
Summary of the full Reasoning GP vomiting in children algorithm, which holds the history, examination, investigations and evidence. Sources: NICE CG84, NG143, NG1, NG18, NG224; UKHSA children's settings guidance and Green Book chapter 27b; MHRA. Clinical reference — follow local paediatric pathways and check doses in the SPC and your local formulary.