You just left the doctor’s office and he told you that you have Crohn’s Disease or Ulcerative Colitis. It was a fifteen minute appointment, you were given some medication, and told to return for a follow up visit in three months. You have a million questions, but you did not have a chance to ask a single one. The information on the internet just confuses you more.

Here is what you need to know:

  • “Inflammatory Bowel Disease (IBD)” is a general term that includes two disease--Crohn’s disease and Ulcerative Colitis. These two diseases are similar, but have some major differences (see below). Both cause similar symptoms, the most common ones are abdominal pain, diarrhoea, rectal bleeding, and weight loss. Some people have only one symptom, some have many. Some people have mild disease while others have severe symptoms which can significantly interfere with their lives. 
  • People with Crohn’s Disease and Ulcerative Colitis have inflammation of the intestinal tract. The easiest way to think of inflammation is to think of an infected gets red, swollen, and irritated. Inflammation is usually the result of the body fighting an infection.  Our white blood cells attack the infection (usually a bacteria or a virus) by releasing chemicals called “cytokines” that kill the infecting organisms. But these cytokines also injure our own tissues in the process, resulting in redness and swelling. Eventually the body gets rid of the infection and the inflammation resolves.

In Crohn’s Disease and Ulcerative Colitis there is no infection. For unknown reasons, the 
body attacks the intestines as if they were infected. White blood cells release these cytokines and the lining of the intestinal tract (called the mucosa) becomes inflamed.  Usually when people first present with symptoms, the doctor will want to check for infections since they can produce identical symptoms. But infections usually resolve in a week or two. Crohn’s and Ulcerative Colitis, on the other hand, are chronic, which simply means that they last for a long time. The inflamed intestines can be seen at the time of a colonoscopy. The lining (mucosa) becomes red (the medical term is “erythematous”), can bleed easily (called “friable”), and have ulcers (an ulcer just means an area where the mucosa has eroded away. They look like little craters).

  • Your intestinal tract includes your oesophagus (feeding tube), stomach, small intestine (about 7 metres long and divided into sections called the duodenum, jejunum, and ileum), and large intestine (also called the colon, which is about 1.5 metres long). In medical language when there is inflammation, doctors add the ending “itis”. So, for example, “colitis” means inflammation of the colon and “ileitis” means inflammation of the ileum. The only exceptions are inflammation of the rectum, which is called “proctitis, and inflammation of the stomach, which is called “gastritis”.

Ulcerative Colitis is a disease that only affects the colon (which is why it is called Ulcerative COLITIS). Only a section of the colon may be inflamed or the entire colon can be involved. When just the rectum is inflamed, it is called ulcerative proctitis. When the entire colon is involved, it is sometimes called pan-ulcerative colitis. Usually the more colon that is involved, the worse the symptoms.

Crohn’s disease, on the other hand, can affect any part of the intestinal tract. The most common areas that are affected are the colon and the end of the small intestine, the ileum. Therefore, some people will have Crohn’s colitis, some will have Crohn’s ileitis, and some will have both  Crohn’s colitis and ileitis.

In addition to the inflammation in the intestinal tract, people with IBD can occasionally get symptoms causes by inflammation in other parts of the body. Some people can develop arthritis, skin rashes, inflammation of the liver, and eye infections. These “extra-intestinal manifestations” are relatively uncommon.

  • How common are these diseases? Very common. It is estimated that there are between 15-20,000 people with IBD in New Zealand. While symptoms can present at any age, most people are diagnosed in early adulthood. But the the disease can affect young children as well in the very elderly. What causes people to get IBD is unknown.



Prior to making a diagnosis and after a diagnosis of IBD is made, there are several tests your doctor may order.



This stands for a “complete blood count”. There are several things that are reported in CBC. But, simply, it tells the levels of two types of cells in the blood: the white blood cells (which fight infection) and the red blood cells (which carry oxygen to the cells in our body).

   White blood Cells (WBC’s): People with IBD sometimes have a high WBC count because the body is stress or if there is an infection.

   Red Blood Cells (RBC’s): The RBC count can be low in people with IBD due to loss of blood in the stool or from problems absorbing nutrients like iron and vitamin B12 (which are needed to manufacture the red blood cells). RBC’s contain haemoglobin which is the molecule in the red blood cell that carries the oxygen to the cells in our body. A low haemoglobin and a low RBC count mean the same thing. And when they are low, it is called “anaemia”. The most common symptoms of anaemia are tiredness and fatigue. Your doctor might routinely check your B12 and iron levels since supplements can correct or prevent anaemia.


Albumin is blood protein. A low albumin in the blood might be a reflection that you are not well nourished or are not absorbing foods well.


CRP stands for “C-reactive protein”. It is a protein in the blood that tends to go up when there is any kind of inflammation, like IBD,  in the body. However, a normal CRP does not mean that there is no inflammation.

Faecal (stool) Calprotectin

When there is inflammation in the intestines, as we explained earlier, there are usually white blood cells present. Calprotectin is a protein that is found in white blood cells. When the calprotectin level in the stool is high, it is an indication that there is inflammation in the intestinal tract. The stool calprotectin correlates better with the activity of IBD than a CRP (above), but is a more expensive test and you will need to bring in a stool sample.

Stool Cultures

Since intestinal infections can cause the same symptoms as IBD, your doctor might want to make sure there is no infection. People with IBD are also more prone to getting infections. If you have a flare of your symptoms, it might be important to be certain it is the IBD acting up, rather than an infection, since the treatment will be different.



Endoscopies are tests using flexible tubes with a light and a TV camera in the tip which show the inside lining of the intestines. After checking blood and stool tests, most doctors will want to do one of these exams as they are the best tests to diagnose IBD or to evaluate whether you are experiencing a flare. Samples of the lining of the intestine (biopsies) can be taken and checked under a microscope to help make the diagnosis. 


A Colonoscopy is an examination in which a long tube (a colonoscope) is passed the entire length of the colon and into the end of the small intestine, the ileum. It is  the most accurate way to check for or evaluate the severity of Crohn’s disease or Ulcerative Colitis. People are sedated for this examination. It requires a prep of laxatives and a special diet to clean out the intestines so the doctor can get a good look at the lining. 

Flexible Sigmoidoscopy

flexible sigmoidoscopy is a more limited examination of the colon in which the colonoscope is passed a short distance into the colon (about 60 cm). It is a useful test, particularly to evaluate the activity of Ulcerative Colitis since Ulcerative Colitis always affects the colon. It is not as good a test for Crohn’s disease since Crohn’s usually affects the intestine higher up.  People are usually prepped with an enema and may or may not receive sedation.


A gastroscopy is another endoscopy in which a very thin tube is passed through the mouth to examine  the stomach and the first part of the small intestine. Since IBD most commonly affects the end of the small intestine and the colon, it is only occasionally performed if involvement of the upper intestinal tract is suspected.

Capsule Endoscopy

A capsule endoscopy is sometimes done because the small intestine is about 7 metres long and too long for most endoscopes. This  procedure uses a capsule with a miniature video camera inside. After a person swallows the capsule, it transmits a video movie of the small intestine as it travels through the GI tract. It is used if a person has a normal colonoscopy and the doctor still suspects there may be Crohn’s disease in the part of the small intestine that is out of reach of the colonoscope.



Another way to see if there is involvement of Crohn’s disease in the small intestine above the level that can be seen with a colonoscope is with a special CT scan or MRI of the small intestine.   A CT scan  is a sophisticated xray which uses a computer to generate the xray picture. If a segment of the small intestine is inflamed, the wall will looked thickened. An MRI is a similar study that uses a magnet to generate the picture. It has the advantage that there is no xray exposure. 




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