How is Crohn’s disease diagnosed?
Crohn’s disease is suspected in people who have been experiencing symptoms such as chronic abdominal pain, diarrhoea, and weight loss. Symptoms that lasts for weeks or months are key areas for suspicion of Crohn’s disease. As the Crohn’s disease can mimic the similar conditions, and has no single conclusive test to establish its diagnosis, it can take time to correct arrive at this diagnosis. The medical investigation will include a series of Crohn’s disease specific tests to come to a conclusion:
- Complete personal medical history, including full review of all symptoms
- Complete family history
- Physical examination
- Examination of stool samples to rule out infectious diseases or check for blood in the stool
- Complete blood count (CBC) or full blood count (FBC), which can provide additional clues to one’s overall health. For example, low levels of red blood cells can suggest internal bleeding and the presence of anaemia. A high white blood cell count, a higher-than-normal level of C-reactive protein (CRP), or a high erythrocyte sedimentation rate (ESR) can indicate the presence of inflammation somewhere in the body.
- Internal investigations, including:
- Taking of barium sulphate suspension, followed by x-rays to show areas of inflammation in the stomach and the small intestine
- Barium enema (if the disease is suspected lower down the GI tract) followed by x-rays to show areas of inflammation in the colon and rectum
- Endoscopy, to determine the extent and severity of disease. Depending on the suspected location of the inflammation, there are a number of different endoscopy procedures that will be performed, including:
- sigmoidoscopy if examination is limited to the rectum and sigmoid colon
- colonoscopy if the entire colon is viewed
- ileocolonoscopy if the colon and distal ileum are viewed
- enteroscopy if the small bowel is viewed
- gastroscopy if the stomach and upper duodenum are viewed.
During these procedures, a biopsy (examining a small sample of tissue under a microscope) might be done. The characteristic pattern of Crohn’s disease under microscopic examination can distinguish it from other diseases of the colon, such as ulcerative colitis or colorectal cancer.
Other types of investigations that are helpful in diagnosing Crohn’s disease are computed tomography (CT) scanning, magnetic resonance imaging (MRI), and ultrasound. All of these investigations give the medical team a look inside the body without the need for invasive procedures such as the insertion of a needle or instrument. Your clinical team will advise you if any of these procedures is right for you.