What is …? — Glossary

Plain-language definitions of the ostomy and IBD terms you meet in reports, appointments, and forums. Sourced, not medical advice.

Diseases & core concepts

Crohn's disease

Crohn's disease is a long-term inflammatory bowel disease that can inflame any part of the digestive tract, from the mouth to the anus, though it most often affects the end of the small intestine. The inflammation can reach through the full thickness of the bowel wall and tends to appear in patches, with healthy tissue in between.

Inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is an umbrella term for long-term conditions that cause chronic inflammation of the digestive tract. Its two main forms are ulcerative colitis and Crohn's disease. IBD is not the same as IBS: IBD involves real inflammation and tissue damage, while IBS does not.

Irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS) is a common, long-term disorder of how the gut and brain work together. It causes symptoms like cramping, bloating, diarrhoea and constipation, but unlike inflammatory bowel disease it does not inflame or damage the bowel, and it does not raise the risk of bowel cancer.

Ulcerative colitis

Ulcerative colitis is a long-term inflammatory bowel disease in which the lining of the colon and rectum (the large intestine) becomes inflamed and develops small open sores called ulcers. It usually follows a relapsing pattern of flare-ups and calmer periods called remission.

Disease course & symptoms

Fistula

A fistula is an abnormal tunnel that forms between two parts of the body that are not normally connected, such as between the bowel and the skin, the bladder, or another loop of bowel. Fistulas are a known complication of Crohn's disease, and most need medical treatment rather than healing on their own.

Flare-up

A flare-up, or flare, is a period when inflammatory bowel disease becomes active again and symptoms return or get worse after a calmer spell. A flare can bring more diarrhoea, abdominal pain, bleeding and fatigue, and it often means treatment needs reviewing.

Remission

Remission is a period when inflammatory bowel disease quiets down and symptoms become very mild or disappear. It does not mean the disease is cured; it means it is under control, usually with treatment, and reaching and staying in remission is the main aim of IBD care.

Stricture

A stricture is a narrowing of a section of bowel, caused by inflammation, scar tissue, or both. It can slow or block the passage of stool and may lead to a bowel obstruction. Strictures are a common complication of long-standing Crohn's disease.

Surgery & stoma terms

Colostomy

A colostomy is a stoma made from the large bowel (colon), so stool leaves the body through an opening on the abdomen instead of through the rectum. Because the colon has already absorbed most of the water, the output tends to be more formed.

Ileostomy

An ileostomy is a stoma made from the end of the small intestine (ileum), usually on the right side of the abdomen. The output is liquid to porridge-like and flows continuously, so staying hydrated matters more than with a colostomy.

J-pouch

A J-pouch is an internal reservoir a surgeon makes from the end of the small intestine and connects to the anal canal, so a person can pass stool the normal way instead of living with a permanent stoma. It is most often done for ulcerative colitis after the colon and rectum are removed.

Stoma

A stoma is a surgically made opening on the abdomen that lets stool or urine leave the body when part of the bowel or urinary tract is bypassed or removed. It has no nerve endings, so it does not hurt to touch.

Stoma reversal

A stoma reversal is an operation that reconnects the bowel and closes a temporary stoma, so stool passes through the anus again. It applies to temporary loop stomas, usually after the bowel has healed, and not everyone is a candidate.

Urostomy

A urostomy is a stoma that drains urine rather than stool. A surgeon uses a short piece of small intestine to carry urine from the ureters to an opening on the abdomen, where it collects in a pouch. The most common reason is removal of the bladder.

Diagnosis & monitoring

Biopsy

A biopsy is when a small sample of tissue or cells is taken from the body so a pathologist can examine it under a microscope. In bowel conditions it is often taken painlessly during a colonoscopy and is what confirms a diagnosis.

Colonoscopy

A colonoscopy is an exam that looks at the inside lining of the large bowel (colon) and rectum using a colonoscope, a thin flexible tube with a small camera. Tissue samples and polyps can be taken during the same procedure.

Fecal calprotectin

Fecal calprotectin is a stool test that measures a protein released by white blood cells when the intestines are inflamed. It helps tell inflammatory bowel disease apart from non-inflammatory conditions like IBS, without an invasive procedure.