Definition and types of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a term used to describe chronic disorders that cause inflammation of the gastrointestinal tractGastroenterological Society of Australia (GESA), 2018.

The most common types of inflammatory bowel disease are Crohn disease and ulcerative colitis. Crohn disease and ulcerative colitis have many overlapping radiological, endoscopic, clinical and histological features. The main differences between the diseases are the area of the gastrointestinal tract that they affect, and the type of inflammation present. In ulcerative colitis, inflammation is generally limited to the mucosal layer of the colon and is continuous, usually extending from the rectum for a variable distance towards the caecum. In Crohn disease, inflammation affects all layers of the intestinal mucosa in any part of the gastrointestinal tract, and can be discontinuousGastroenterological Society of Australia (GESA), 2018.

Other types of inflammatory bowel disease include infectious colitis, microscopic and collagenous colitis, ischaemic colitis, eosinophilic colitis and granulomatous colitis. Infectious colitis can be excluded using stool examination; see Aims of assessment and differential diagnosis of gastroenteritis for information about assessment of a patient with diarrhoea. Microscopic colitis and collagenous colitis should be considered in patients where the colon is endoscopically normal but there are histological signs of inflammation. Ischaemic colitis should be considered in patients with risk factors such as advanced age or a history of cardiovascular disease.

A consumer information leaflet about inflammatory bowel disease is available from the Gastroenterological Society of Australia website. Contacting other patients with inflammatory bowel disease through Crohn’s & Colitis Australia is often helpful for patients.