Special investigations of Crohn's disease

Blood investigations might be normal. Anaemia or a raised sedimentation rate (a non-specific indicator of activity of disease) should not be ignored. Crohn’s of the colon can be detected by performing a colonoscopy, an investigation where a flexible fibre-optic instrument is passed via the rectum to the rest of the colon, visualising the colon and taking biopsies for histological examination of all suspicious areas.

The small bowel is investigated by performing a small bowel enema where a thin tube is passed through the nose, placed beyond the stomach and a special radio-opaque solution passed via the tube to fill the entire small bowel while X-ray pictures are taken.

The swelling of the mucosal lining of the small bowel caused by Crohn's encroaches on the radio-opaque material causing the so-called "string sign", or can render a spiky appearance to the bowel wall caused by small abscesses.

A CT or MRI scan of the abdomen and pelvis can be useful in determining the extent of the bowel involvement.

Reviewed by Dr Ismail Moola MBCHB (UCT) FCP (SA) Cert Gastro Phys (SA)
Specialist Physician / Gastroenterologist Netcare Sunninghill Hospital and part time Lecturer Department of Internal Medicine, Division of Gastroenterology, Wits University.

Previously reviewed by Prof Don du Toit (M.B.Ch.B) (D.Phil.) (Ph.D) (FCS) (FRCS)