Crohn's disease
Also called: Inflammatory bowel disease, IBD
A lifelong inflammatory bowel disease that can affect any part of the gut from mouth to anus, most often the end of the small intestine. Inflammation is patchy and extends through the whole bowel wall.
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What happens in the body
An abnormal immune response to gut bacteria in genetically susceptible people (e.g. NOD2 variants) causes transmural inflammation, ulcers, strictures and fistulas.
Causes
- Genetic susceptibility combined with an abnormal immune response to gut microbes
Risk factors
- Family history
- Smoking (doubles risk)
- Age 15–35
- Urban and Western diets
Symptoms
- Diarrhoea (sometimes with blood)
- Abdominal pain and cramping
- Weight loss
- Fatigue and fever
- Mouth ulcers
- Perianal abscesses and fistulas
- Growth delay in children
Diagnosis — tests and examinations
- Blood tests and faecal calprotectin
- Colonoscopy with biopsies
- MR enterography
- Capsule endoscopy
Treatment
Medicines and medical treatment
- Steroids or exclusive enteral nutrition for flares
- Immunomodulators (azathioprine, methotrexate)
- Biologics: infliximab, adalimumab, vedolizumab, ustekinumab, risankizumab
- JAK inhibitor upadacitinib
- Antibiotics for fistulas and abscesses
Operations and procedures
- Resection of strictured or diseased bowel
- Strictureplasty
- Fistula surgery
Self-care, home remedies and lifestyle
- Stop smoking — the most important modifiable factor
- Nutritional support and dietitian advice
- Vaccinations before immunosuppression
Possible complications
- Strictures and bowel obstruction
- Fistulas and abscesses
- Malnutrition and anaemia
- Bowel cancer risk
- Joint, skin and eye inflammation
Prevention
- Not smoking
Outlook
Chronic with flares and remissions; modern biologics allow most people to live normal lives.
When to see a doctor
See a doctor for diarrhoea lasting more than 4 weeks, blood in stools or unexplained weight loss.
Sources and further reading
These sources cover this condition. They have not been checked against every statement on this page.
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