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Crohn's disease

What is Crohn's disease?

Crohn's disease is a condition that causes inflammation (swelling and pain) in the wall of the digestive system. Any part of the digestive system can be affected. In about 1/3 of people with Crohn's disease only the large intestine is affected, in about 1/3 only the small intestine is affected, and in about 1/3 both the small and large intestines are affected. (For an illustration and details on the different types of Crohn's disease, see the previous section, How Does the Digestive System Work?

Crohn's disease can be difficult to diagnose because its symptoms are similar to other intestinal disorders and to another type of Inflammatory Bowel Disease (IBD) called ulcerative colitis. Whereas ulcerative colitis affects the inside lining of the colon (large intestine) or rectum, Crohn's disease causes inflammation deeper within the intestinal wall and can occur in other parts of the digestive system, including the small intestine, mouth, esophagus and stomach.

  • What are the symptoms of Crohn's disease?

    The most common symptoms of Crohn's disease are pain, usually in the lower right side of the abdomen, diarrhoea, needing to go to the toilet often, loss of appetite, weight loss, fever and tiredness.

    Your symptoms can depend on which part of the gut is affected. For example, you may not have diarrhoea if only the small intestine is affected. On the other hand, pain in the abdomen without any other symptoms may be caused by a small patch of Crohn's disease in the small intestine.

    In SEVERE cases

    In severe Crohn's disease, additional symptoms include mouth sores and painful 'cracks' in the skin of the anus called anal fissures.

    A severe flare-up can make you feel very ill in general. If large parts of the gut are affected, you may not be able to absorb food well, and you may become deficient in vitamins and other nutrients.

  • How is Crohn's disease diagnosed?                                                       back to top

    Different tests may be used to diagnose Crohn's disease. A physical examination and medical history are usually the first step. Blood tests may also be done to check for anaemia, which could suggest bleeding, or they may uncover a high white blood cell count, which is a sign of inflammation somewhere in the body.

    A stool sample can also reveal white blood cells, which might be an indication of inflammatory disease. A stool sample also allows the doctor to detect bleeding or infection caused by bacteria, a virus or parasites. Ruling out these causes can be useful in diagnosing Crohn's disease.  

    If you have symptoms coming from the colon, your doctor may look inside the colon using a thin, flexible tube connected to a computer and TV monitor, called a sigmoidoscope or a longer flexible colonoscope. Usually the appearance of the inside lining of the colon will help the doctor to diagnose Crohn's disease. The camera is fitted with a device which the doctor can use to take a biopsy (small sample) of the lining of the gut, which is viewed under a microscope. The typical pattern of the cells may suggest Crohn's disease.

    Before the examination, you will need to drink a special preparation which will make you go to the toilet often. This is to clear the digestive system, so the camera can move about, and clearly see the walls of the bowel. Although the examination may be uncomfortable, it shouldn't be painful. Your doctor can discuss options for pain relief with you. If a biopsy is taken, usually this doesn't cause any discomfort.

    If, however, your symptoms are coming mainly from the upper part of the gut, then your doctor may suggest an endoscopy. A thin, flexible telescope is passed down the oesophagus into the stomach, allowing the doctor or nurse to look inside. If a special X-ray of the large intestine or small intestine is used, you will be given a specially prepared drink (barium meal) or an enema (barium enema) before the test. Barium coats the lining of the gut and shows up as white on X-ray films. The patterns on the films show the doctor which parts of the gut are affected by disease.

    Additional tests and scans may be needed, especially if there are complications. For example, CT and MRI scans can be used to obtain detailed pictures of the digestive system.

    In about 10% of people with IBD, it is difficult to determine whether they have ulcerative colitis or Crohn's disease, due to similar or overlapping symptoms.

  • Can other parts of the body be affected also?                                 back to top

    Other parts of the body may also be affected in some people with Crohn's disease, such as the joints, skin, eyes or liver. Some of these problems will improve when the Crohn's disease is treated, but others may require specific treatment as well. Not everyone will have these problems, however.

    in SEVERE cases

    In severe Crohn's disease there may be inflammation and pain in the joints (arthritis); skin rashes; inflammation of the eye (uveitis); or liver inflammation. Doctors call these 'extraintestinal manifestations'.

    Here are a few examples of extraintestinal manifestations of Crohn's disease:

    Peripheral arthropathy or arthritis - mainly soreness in the large and medium-size joints during a flare. The spine and lower back can also be affected. The arthritis may flare up even when the inflammatory disease is under control. Typical treatment may include analgesics (for pain relief).

    Erythema nodosum - the appearance of tender, red nodules, usually on the front area of the legs below the knees. This is more often seen in Crohn's disease than ulcerative colitis, and usually improves on its own in 4-6 weeks, or with treatment for the inflammatory disease. Treatment, when needed, may include corticosteroids or anti-inflammatory medicine.

    Episcleritis - inflammation of the white part of the eye and surrounding tissue, usually painless and often mistaken for pink eye. It usually improves on its own after 1-2 weeks. Treatment may include chilled artificial tears, corticosteroid eye drops or anti-inflammatory medicine.

    Uveitis - inflammation of the iris (coloured part of the eye), which can be very painful and can be associated with visual changes and sensitivity to light. If untreated, uveitis can progress to blindness, so it is important to treat this condition if it develops. Treatment may include eye drops (steroids or pupil dilators) to help reduce the inflammation and pain.

  • Who gets Crohn's disease?                                                               back to top

    About 1 million people in Europe have Crohn's disease. That is about 1 in 1,500 people. It can develop at any age, but most commonly starts between the ages of 15 and 40. It affects women slightly more often than men. The disease has become more common in recent years, although the cause is still unknown. It is more common in people who smoke.

  • What causes Crohn's disease?                                                     back to top

    The cause of Crohn's disease is not yet known, although a combination of factors are believed to play a role, including viruses, bacteria, genetics and smoking. One theory is that a bacteria or virus may trigger the immune system to cause inflammation in parts of the digestive system in people who are genetically prone to develop the disease.

  • How does Crohn's disease progress?                                            back to top

    Crohn's disease is a chronic (ongoing) disease, with times when symptoms flare up (relapse) and times when there are few or no symptoms (remission). The severity of symptoms, and how often they occur, varies from one person to the next. A few people with Crohn's disease just have one or two flare-ups in their life, but for most of their life have no symptoms. A few people have frequent and/or severe flare-ups. Most people fall somewhere in the middle. The first flare-up is usually the worst. Usually, however, with treatment, symptoms can be managed well and it still possible to follow your ambitions and live life to the full.

    in SEVERE cases

    There are several possible complications that can occur in people with Crohn's disease, usually in more severe cases. Here are a few examples:

    Stricture - a narrowing of part of the gut due to scar tissue that has formed. This can cause difficulty in food passing through. If the bowel becomes blocked (an obstruction), this can cause pain and vomiting.

    Perforation - A small hole that forms in the wall of the gut. The contents of the gut can leak out and cause infection or an abscess inside the abdomen. This can be serious and life-threatening.

    Fistula - This is when the inflammation and infection causes a channel to form between two parts of the gut, a nearby organ or the skin, allowing the contents to leak into the other area.

  • Should cancer be a concern?                                                        back to top

    People with Crohn's disease have a small increased risk of cancer in the intestines (bowel cancer) compared to the risk of the general population. The risk of cancer is different depending on how long the person has had the disease and how much of the colon is affected. Your doctor will look for signs of abnormal cells when doing a colonoscopy, sigmoidoscopy or biopsy. If you are concerned about your risk, speak with your doctor.

  • Will I need surgery?                                                                       back to top

    Most people with mild or moderate Crohn's disease are able to manage their symptoms with medication. However, surgery may be needed in people with more severe disease if, for example, there is a complication. After surgery, however, people with Crohn's disease can usually expect a good quality of life.

    Choosing whether to have surgery, and also which surgery to have, depends on the severity of the disease and your needs, expectations and lifestyle. If you are faced with this decision, get as much information as possible by talking to your doctors, to nurses who work with colon surgery patients and to other Crohn's disease surgery patients. Patient support groups can also direct you to other helpful resources and give you the opportunity to meet with other people who are considering similar options, or who have had similar experiences in the past.

    For tips on talking to your doctor about your concerns, see Living with IBD/ Your IBD Consultation. For more information on treatment and surgery for Crohn's disease, please see, Crohn's disease/ Treatment Plan for Crohn's disease.


    in SEVERE cases

    If you do need to consider having surgery, rest assured that you are not alone: As many as 8 in 10 people with Crohn's disease will undergo surgery at some point in their lives, usually due to a complication.

  • What can I do to help manage my illness?                                    back to top

    Your role in managing your illness is very important. Here are some of the most important things you can do to stay in control of ulcerative colitis:

    • Be involved in the proactive management of your own health every day

    • Know when and how to take care of your general health

    • Follow your management plan and take your medication

    • Ask questions if you are concerned, and seek help if a problem arises.

    In between doctor visits. It is important that you follow your treatment plan and know what to do should a problem arise. If you have any of these problems, contact your doctor as soon as possible:

    • Blood in your stool

    • Change in bowel habits that last for more than 10 days

    • Severe abdominal cramps or pain

    • Severe diarrhoea or bloody diarrhoea

    • Weight loss with no known reason

    • Unexplained fever lasting more than 3-4 days

    • Constant fatigue

    • Loss of appetite

    • Nausea or vomiting for unknown reasons

in SEVERE cases

If you have severe disease, learn to listen to your body and if you think something may be wrong, it is best to take action and check with your doctor. If something is wrong, you will catch it early. If nothing is seriously wrong, at least you will be reassured.




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