Definition and epidemiology
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder (disorder of gut–brain interaction) defined by recurrent abdominal pain associated with defecation and/or a change in stool frequency or form, in the absence of an organic explanation. It is among the commonest functional GI disorders in children over four years, contributing to an overall pediatric FGID prevalence of roughly 20%. Pathophysiology is biopsychosocial — visceral hypersensitivity, altered motility, gut–brain axis and microbiome changes, post-infectious sensitisation, and psychological factors (anxiety, somatisation, school stress). IBS is a positive symptom-based diagnosis, not a diagnosis of exclusion requiring exhaustive testing.
Clinical features
- Recurrent abdominal pain related to defecation (better or worse with stooling)
- Pain associated with a change in stool frequency and/or change in stool form/appearance
- Subtypes by predominant stool form (Bristol scale): IBS-C (constipation), IBS-D (diarrhoea), IBS-M (mixed), IBS-U (unsubtyped)
- Bloating, urgency, sensation of incomplete evacuation, mucus
- Frequent overlap with functional dyspepsia, headaches, and anxiety/depression
Crucially, in IBS the pain is not relieved purely by resolution of constipation — if it is, the diagnosis is functional constipation rather than IBS.
Diagnosis
Diagnosis uses the Rome IV symptom-based criteria for child/adolescent FGIDs. IBS requires all of the following, fulfilled for at least 2 months before diagnosis:
- Abdominal pain at least 4 days per month associated with one or more of: relation to defecation; a change in stool frequency; a change in stool form/appearance
- In children with constipation, the pain does not resolve with resolution of the constipation (otherwise → functional constipation)
- After appropriate evaluation, the symptoms cannot be fully explained by another medical condition
Testing should be targeted, not reflexive: a careful history and examination plus growth review usually suffice. Consider limited workup (CBC, inflammatory markers, coeliac serology, stool studies) where the history warrants, and escalate only if alarm features are present.
See the full criteria: Irritable Bowel Syndrome
Red flags (mandate evaluation for organic disease)
- Unintentional weight loss, growth failure, or delayed puberty
- GI bleeding (haematochezia, melaena) or unexplained anaemia
- Nocturnal pain or diarrhoea that wakes the child
- Persistent vomiting, dysphagia, or right-lower-quadrant pain/mass
- Fever, perianal disease, oral ulceration, arthritis (consider IBD)
- Family history of IBD, coeliac disease, or peptic ulcer disease
- Pain consistently localised away from the periumbilical region
Management overview
Management is built on a therapeutic clinician–family relationship: a confident positive diagnosis, validation that the pain is real, and explanation of the gut–brain mechanism reduce anxiety and unnecessary testing. Core elements:
- Education and reassurance; set functional goals (return to school/activity) rather than total pain elimination
- Dietary adjustment guided by symptoms (adequate fibre/fluids for IBS-C; a supervised, time-limited low-FODMAP trial in older children where indicated — avoid unnecessarily restrictive diets)
- Psychological therapies with the best evidence — cognitive behavioural therapy and gut-directed hypnotherapy
- Treat the predominant bowel disturbance and address comorbid anxiety/sleep
- Pharmacologic agents (antispasmodics, neuromodulators, osmotic laxatives, anti-diarrhoeals) are adjuncts for refractory symptoms, individualised with specialist input; no specific doses are given here
Most children improve over time; persistent or escalating symptoms warrant re-evaluation for emerging organic disease.
References
- Hyams JS, et al. Childhood functional GI disorders: child/adolescent (Rome IV). Gastroenterology. 2016;150:1456–1468.
- Drossman DA. Functional GI disorders and Rome IV. Gastroenterology. 2016;150:1262–1279.
- NASPGHAN/ESPGHAN guidance on functional abdominal pain disorders.
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.