Glossary of Terms

Listed below are many words you may come across concerning your disease. Use the site’s search function or Ctrl+F to quickly search terms.


5-ASA: 5-Aminosalicylic acid or mesalazine. 5-ASA is delivered to the small and large intestine where it is active against the inflammation seen in inflammatory bowel disease.

Abscess: A localised collection of pus in a cavity formed by the decay of diseased tissues.

Acute: Sudden onset of symptoms (as in relapse).

Aetiology: Cause.

Anaemia: Illness caused by a reduction in the number of red blood cells in the body, which results in insufficient oxygen being carried by the blood to the organs of the body.

Anastamosis: The joining together of two ends of healthy bowel after diseased bowel has been cut out (resected) by the surgeon.

Ankylosing spondylitis: Chronic inflammatory disease of the spine and nearby joints which can cause pain and stiffness in the spine, neck, hips, jaw and rib cage.

Antigens: Foreign substances within the body that are recognised by the immune system and are capable of inducing an immune reaction. Anus: The opening to the back passage.

Arthralgia: Pains in the joints.

Arthritis: Inflammation of a joint(s) causing pain, swelling and stiffness.

Ascending colon: The portion of bowel extending from the caecum to the hepatic flexure.

Balloon catheter: An inflatable plastic cylinder mounted on a thin tube and used for dilating narrowed areas of intestine.

Biopsy: Removal of small pieces of tissue from parts of the body (e.g. colon – colonic biopsy) for examination under the microscope for diagnosis.

Bulk laxative: see laxative.

Bulking agent: A form of fibre made into tablets, granules or a powder (to be mixed with water). Bulking agents are used to regulate bowel movements, to treat either constipation or diarrhoea, by varying the amount of liquid taken with them.

Caecum: The first part of the large intestine. It is a blind-ending pouch at the junction between the small and large intestines.

Chronic: Symptoms occurring over a long period of time.

Cobblestoning: Characteristic appearance of the intestinal lining in Crohn’s disease. The ‘cobblestone’ effect is the result of deep ulceration and swelling of the surrounding tissue.

Colitis: Inflammation of the colon.

Colon: The large intestine. It extends from the caecum to the rectum and has ascending, transverse and descending portions.

Colonoscopy: Inspection of the colon by an illuminated telescope called a colonoscope.

Colostomy: Surgical creation of an opening between the colon and the surface of the body. Part of the colon is brought out onto the abdomen to create a stoma. A bag is placed over this to collect waste material.

Constipation: Infrequency or difficulty in the passage of bowel motions.

Corticosteroids: Natural substances produced by the body that act against the inflammation seen in inflammatory bowel disease.

Crohn’s Disease Activity Index (CDAI): Measurement of the severity of active disease using symptom scores that are monitored over 1 week.

CT scan: Computerised tomography scan. A specialised form of X-ray examination that produces cross-sectional images of the body.

Defaecation: The act of passing faeces.

Descending colon: The portion of bowel between the splenic flexure and the sigmoid colon.

Diarrhoea: An increase in frequency, liquidity and weight of bowel motions (normal production 200 g in 24 hours).

Distal: Further down the bowel towards the anus.

Diverticulum (plural diverticula): Small pouch-like projection through the muscular wall of the intestine; may become infected, causing diverticulitis.

Dysplasia: An abnormality in the development of adult cells, leading to an alteration in cell size, shape or organisation.

Dysuria: Pain on urination.

Electrolytes: Salts in the blood, e.g. sodium, potassium, calcium.

Elemental diet: A liquid diet containing simple forms of protein, carbohydrates and fats, which can be absorbed without further digestion. Elemental diets are usually consumed for two weeks before normal foods are re-introduced in a systematic way.

Endoscopy: A collective name for all visual inspections of body cavities with an illuminated telescope. Examples are colonoscopy and sigmoidoscopy.

Enema: A liquid (e.g. barium) introduced into the rectum for treatment, diagnostic purposes or to stimulate the production of a bowel motion.

Erythema nodosum: Red, tender swellings occasionally seen on the shins and lower legs during a flare-up of inflammatory bowel disease. They usually subside when the disease is in remission.

Erythrocytes: Red cells in the blood that carry oxygen.

Exacerbation: An aggravation of symptoms.

Exclusion diet: A diet that initially excludes a number of foods that have been found to provoke symptoms in the majority of individuals with food sensitivities.The excluded foods are then re-introduced one by one and if symptoms re-occur that food is excluded for a longer period (usually one year).

Faeces: The waste matter eliminated from the body through the anus (other names are stools and motions).

Fibre optic: Flexible fibres that carry light, e.g. in a colonoscope.

Fibrosis: The formation of fibrous connective tissue, usually as a consequence of inflammation.

Fissure: A cleft or groove (crack) in the surface of the skin.

Fistula: An abnormal connection, usually between two organs or leading from an internal organ to the surface of the body.

Flatus: Gas from the rectum.

Food intolerance: An adverse reaction to food that does not involve the immune system and therefore differs from a food allergy.

Fulminant colitis: Colitis occurring suddenly with great intensity and severity.

Gastroenteritis: Inflammation of the stomach and intestine.

Granulomas: Nodules of cells, surrounded by lymphocytes, which can be found in all layers of the bowel. If present, they strongly suggest Crohn’s disease.

Haematochezia: The passage of bloody stools.

Haemorrhoids: Swollen veins in the area of the anus. They bleed easily and are often painful.

Harvey and Bradshaw Index: Simple measurement of disease activity in Crohn’s disease measured over a 24-hour period.

Hepatic flexure: That part of the colon where the ascending and transverse portions meet, below the liver.

Heredity: The transmission of characteristics from parent to child.

Histology: The examination of tissues under the microscope to assist diagnosis.

Hypoalbuminaemia: Decreased levels of albumin (protein) in the blood.

Hypokalaemia: Decreased levels of potassium in the blood.

Ileo-anal anastomosis: The formation of a pouch by re-fashioning loops of ileum into a reservoir, making an artificial rectum and joining it to the anus (known as a Park’s pouch).

Ileostomy: This is when the open end of the healthy ileum is diverted to the surface of the abdomen and secured there to form a new exit for waste matter.

Ileum: The lowest part of the small intestine.

Immune response: The body’s reaction to invasion by foreign substances; it involves inflammation of the affected part of the body.

Immunosuppressed: A person’s immune response is not activated by a foreign substance.

Inflammation: The body’s natural defense mechanism in which blood rushes to any site of damage or infection causing reddening, swelling and pain.The area is usually hot to touch.

Irritable bowel syndrome: Increased sensitivity of the intestine, characterised by recurrent abdominal cramps, bloating, mucus in stools, irregular bowel habits, diarrhoea and constipation.

Iritis: Painful inflammation of the eyes.

Jejunum: The portion of the small intestine that lies between the duodenum and the ileum.

Laxative: An agent that acts to cause emptying of the bowel. This may be by purging (irritating the lining) or increasing the volume of stools (bulking).

Lesion: A term used to describe any structural abnormality in the body.

Leucocytes: White cells in the blood that help fight infection.

Leucocytosis: An increase in the number of circulating white cells in the blood.

Leucopenia: A decrease in the number of circulating white cells in the blood.

Lymphocytes: A particular kind of leucocyte.

MRI scan: Magnetic resonance imaging scan. A diagnostic technique that uses high-frequency radio waves and a computer to visualise the organs of the body. It does not use potentially harmful X-rays.

Mucus: A white, slimy lubricant produced by the intestines. It is found in excess in the stools of patients with colitis.

Nausea: Feeling sick.

Oedema: Accumulation (build-up) of excessive amounts of fluid in the tissues resulting in swelling.

Oesophagus: The portion of the intestine that runs from the throat to the stomach. Also known as the ‘gullet’.

Osteoporosis: Thinning of the bones due to calcium loss. May be caused by long-term use of steroids or low levels of the hormone oestrogen.

Pathogen: A harmful organism causing disease.

Pathology: The study of the cause and progress of disease.

Perforation: An abnormal opening (hole) in the wall of the bowel that causes the contents of the bowel to spill into the abdominal cavity.

Peri-anal: Around the anus.

Peritoneum: The membrane lining the abdominal cavity.

Peritonitis: Inflammation of the peritoneum, often due to a perforation.

Polyp: A protruding growth from the lining of the intestine (e.g. colonic polyp–a polyp in the colon).

Pouchitis: Inflammation of an ileo-anal anastomosis.

Proctitis: Inflammation of the rectum.

Prophylaxis: Treatment to prevent a disease occurring before it has started.

Proximal: Further up the bowel towards the mouth.

Pyoderma gangrenosum: A type of chronic skin ulceration that sometimes occurs on the limbs of people with inflammatory bowel disease.

Radiologist: The specialist who interprets X-ray pictures to make a diagnosis.

Rectosigmoid area: The junction between the sigmoid colon and the rectum.

Rectum: The lowest 20 cm of the large intestine, just above the anus.

Relapse: Return of disease activity.

Remission: A lessening of symptoms of the disease and a return to good health.

Sacroileitis: Inflammation of the joint between the backbone and the pelvic bone.

Short bowel syndrome: A condition resulting from extensive surgical resection of the small intestine, in which the absorption of nutrients is reduced.

Sigmoid colon: The portion of the colon shaped like the letter ‘S’ or the letter ‘C’, extending from the descending colon to the rectum.

Sigmoidoscopy: Inspection of the sigmoid colon with an illuminated telescope called a sigmoidoscope.

Skip lesions: Areas of inflammation between areas of normal intestinal lining (seen in Crohn’s disease).

Splenic flexure: The portion of the colon in which the transverse and the descending colon meet, below the spleen.

Steatorrhoea: Presence of excess fat in the faeces.

Stoma: An opening into the body from the outside, created by a surgeon.

Stricture: The narrowing of a portion of the bowel.

Suppository: A bullet-shaped solid medication put into the rectum.

Tenesmus: Persistent urge to empty the bowel caused by an inflamed rectum.

Terminal ileum: The last part of the ileum, where the small intestine joins the large intestine.

Total parenteral nutrition: When the whole diet (i.e. all necessary nutrients) is delivered by injection into a vein. Also known as TPN.

Toxic megacolon: A dilatation (swelling) of the colon that may lead to perforation, usually in a very severe attack of ulcerative colitis or Crohn’s disease. Urgent surgery is almost always needed.

TPN: see total parenteral nutrition.

Transverse colon: The portion of bowel between the hepatic and splenic flexures.

Tumour: An abnormal growth that may be benign (non-cancerous) or malignant (cancerous).

Ultrasound: Use of high-pitched sound waves to produce pictures of organs on a screen for diagnostic purposes.

Uveitis: Inflammation of the part of the eye that regulates the amount of light entering the eye.