Paeds · gastroenterology-hepatology-and-nutrition
Acute gastroenteritis and infectious diarrhoea
Also known as Acute gastroenteritis · AGE · Infectious diarrhoea · Gastro · Viral gastroenteritis · Rotavirus gastroenteritis · Norovirus · Dysentery · Bloody diarrhoea · Acute diarrhoea · Diarrhoea and vomiting · Dehydration in children
Fellowship guide to acute gastroenteritis and infectious diarrhoea in children: the commonest reason a child becomes acutely dehydrated, and the condition in which getting rehydration right saves lives while over-investigation and needless drugs do harm. The page covers the viral, bacterial and parasitic causes and the split between watery and bloody diarrhoea, the mechanism by which fluid is lost and the reason oral rehydration solution works through the intact sodium-glucose co-transporter, the disciplined clinical assessment of dehydration, the evidence that oral rehydration therapy beats intravenous fluids for most children, and the layered management of rehydration, early feeding, zinc, ondansetron and the narrow indications for antibiotics, with rotavirus vaccine as prevention.
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Red flags
- Bloody diarrhoea with fever points to invasive bacterial dysentery (Shigella, Campylobacter, Salmonella) or, if with pallor and reduced urine, to Escherichia coli O157 and haemolytic uraemic syndrome — do not reach for antibiotics reflexively, because they can precipitate haemolytic uraemic syndrome in Shiga-toxin infection
- Bilious (green) vomiting, a distended tender abdomen or absent bowel sounds is not gastroenteritis until a surgical cause such as intussusception, malrotation with volvulus or obstruction has been excluded
- Lethargy, sunken eyes, cold mottled peripheries, weak pulse and prolonged capillary refill signal severe dehydration or shock and demand immediate intravenous or intraosseous fluid resuscitation, not oral rehydration
- A child who is not passing urine, has no tears and a very slow skin pinch has severe fluid depletion and needs urgent assessment of electrolytes and glucose
- Diarrhoea lasting beyond fourteen days, or with weight loss and faltering growth, is persistent or chronic diarrhoea and needs a different work-up rather than repeated courses of the acute pathway
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- Normal fluid and electrolyte physiology in children
- Acute gastroenteritis and the dehydrated child
- Oral rehydration therapy and its evidence base
- Assessment and grading of dehydration in children
- Rehydration strategies: oral, nasogastric and intravenous
- Rational use of antibiotics, zinc and antiemetics in diarrhoea
- The child with diarrhoea and vomiting
- Managing dehydration and preventing hospitalisation
- Bloody diarrhoea and its complications
- Long case: the child with recurrent gastroenteritis and its social context
- Short case: assessment of hydration in a child
- Gastroenterology: acute gastroenteritis and dehydration
- Fluid and electrolyte management in acute illness
- Acute gastroenteritis and infectious diarrhoea
- Dehydration assessment and rehydration
- Assessment and management of the dehydrated child
- Acute gastroenteritis
- Dehydration and rehydration
- Infectious diarrhoea
- Medical Knowledge: acute gastroenteritis and dehydration
- Medical Expert: acute gastroenteritis and infectious diarrhoea
Overview & Definition
A toddler is brought in after two days of watery diarrhoea and vomiting. He has stopped eating, his nappies are drier than usual, and his mother is frightened. This is one of the commonest presentations in paediatrics, and the whole art of managing it lies in a single question: how dehydrated is this child, and can I put the fluid back safely by mouth? Everything else — the stool cultures, antiemetics, antibiotics — is secondary to answering that. [1] [2]
Acute gastroenteritis is an inflammation of the stomach and intestine, usually infectious, that causes a sudden increase in stool frequency or looseness, often with vomiting, fever and abdominal pain, and lasting less than two weeks. The clinical danger is not the infection itself, which is usually self-limiting, but the dehydration and electrolyte disturbance that follow the loss of water and salt in the stool and vomit. [2] [1]
The examiner's framework is simple and durable. Decide whether the child is dehydrated and how badly, rehydrate by the safest effective route, feed early, add the few adjuncts that help — zinc and, for the vomiting child, ondansetron — and reserve antibiotics for the narrow group who need them. Prevention through the rotavirus vaccine sits alongside treatment as the other half of the story. [1] [9]
References14ShowHide
- [1]Guarino A; Ashkenazi S; Gendrel D; et al European Society for Pediatric Gastroenterology, Hepatology, and Nutrition/European Society for Pediatric Infectious Diseases evidence-based guidelines for the management of acute gastroenteritis in children in Europe: update 2014. J Pediatr Gastroenterol Nutr, 2014.PMID 24739189
- [2]Pieścik-Lech M; Shamir R; Guarino A; et al Review article: the management of acute gastroenteritis in children. Aliment Pharmacol Ther, 2013.PMID 23190209
- [3]Steiner MJ; DeWalt DA; Byerley JS Is this child dehydrated? JAMA, 2004.PMID 15187057
- [4]Bailey B; Gravel J; Goldman RD; et al External validation of the clinical dehydration scale for children with acute gastroenteritis. Acad Emerg Med, 2010.PMID 20624137
- [5]Lazzerini M; Wanzira H Oral zinc for treating diarrhoea in children. Cochrane Database Syst Rev, 2016.PMID 27996088
- [6]Collinson S; Deans A; Padua-Zamora A; et al Probiotics for treating acute infectious diarrhoea. Cochrane Database Syst Rev, 2020.PMID 33295643
- [7]Szajewska H; Berni Canani R; Domellöf M; et al Probiotics for the Management of Pediatric Gastrointestinal Disorders: Position Paper of the ESPGHAN Special Interest Group on Gut Microbiota and Modifications. J Pediatr Gastroenterol Nutr, 2023.PMID 36219218
- [8]Lifschitz C; Kozhevnikov O; Oesterling C; et al Acute gastroenteritis-changes to the recommended original oral rehydrating salts: a review. Front Pediatr, 2023.PMID 38192370
- [9]Henschke N; Bergman H; Hungerford D; et al The efficacy and safety of rotavirus vaccines in countries in Africa and Asia with high child mortality. Vaccine, 2022.PMID 35184924
- [10]GBD 2023 Diarrhoeal Diseases Collaborators Global burden of enteric infectious diseases, diarrhoeal diseases, and corresponding aetiologies, 1990-2023: a systematic analysis for the Global Burden of Disease Study 2023. Lancet Infect Dis, 2026.PMID 42229499
- [11]Mwendera CA; Yilma M; Wairimu C; et al Burden of Shigella and enterotoxigenic Escherichia coli infections among children under 5 years in Ethiopia, Kenya and Malawi: a systematic review and meta-analysis. BMJ Glob Health, 2026.PMID 41771662
- [12]Shankar J; Nagpal R; Patil A; et al From Barriers to Best Practices: Enhancing Oral Rehydration Therapy Utilization for Diarrhea Management in India. J Assoc Physicians India, 2025.PMID 40955904
- [13]Freedman SB; Williamson-Urquhart S; Plint AC; et al Multidose Ondansetron after Emergency Visits in Children with Gastroenteritis. N Engl J Med, 2025.PMID 40673584
- [14]Sumner M; Xie J; Williamson-Urquhart S; et al Persistent Vomiting Among Children With Acute Gastroenteritis: A Secondary Analysis of a Randomized Clinical Trial. JAMA Netw Open, 2026.PMID 42090154