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Crohn's disease

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What is Crohn's disease?

Crohn's disease is a form of inflammatory bowel disease (IBD) that mainly affects the large and small intestines, but can appear anywhere between the mouth and anus. The most common place it occurs is in the ileum, the last part of the small intestine. Like ulcerative colitis, the other common type of IBD, it causes sores in the lining of the intestines and may lead to life-threatening complications. The main symptoms are severe diarrhea, abdominal cramping and general tiredness. Crohn's disease is an autoimmune disease, which occurs when your body's immune system attacks your own tissues. There are several treatment options available, but this condition often requires lifelong management including medications, dietary measures and, in some cases, surgery. Crohn's disease may also be referred to as regional enteritis, ileitis, terminal ileitis, granulomatous enteritis and colitis.

Causes

The inflammation associated with Crohn's disease involves the full thickness of the gut wall. The actual cause of this inflammation is unknown, but a combination of factors are thought to be involved. The current thinking is that an inappropriate response of the immune system is probably central to the cause. Our bodies usually have trillions of 'good' bacteria living in our intestines, helping to break down and absorb nutrients. Parts of these bacteria pass through the lining and become a target for the immune system. Immune cells within the wall of the bowel are activated, releasing immune mediators such as tumor necrosis factor (TNF). This process is thought to be an integral part of how Crohn's disease occurs.

In Crohn's disease, the released immune mediators cause inflammation of the gut wall. 

Risk factors

The following are thought to be risk factors in developing Crohn's disease:

Smoking

Smokers are twice as likely to develop Crohn's disease as non-smokers. Smoking also makes the condition harder to manage, leading to more severe symptoms.

Genetics

Crohn's disease is more common in certain ethnic groups, such as Caucasians and people of Jewish descent. You are also more likely to develop Crohn's disease if you have a close relative who has the condition.

Environmental factors

Crohn's disease is much less common in undeveloped nations, pointing to an environmental link.

Signs and symptoms

Gastrointestinal involvement

The symptoms of Crohn's disease can vary, depending on the extent, location and severity of the condition. A common area involved in Crohn's disease is the last part of the small intestine, called the terminal ileum. Involvement of the large bowel is also common, particularly in combination with terminal ileitis. Less prevalent patterns of involvement are isolated disease around the anus and the stomach and first part of the small intestine. All cases are different, but common symptoms are as follows:

The gastrointestinal system. 

Symptoms from other areas of involvement

Depending on the severity of the condition, there is a wide range of other symptoms that may occur with Crohn's disease, such as:

Methods for diagnosis

Crohn's disease can easily be confused with other conditions that have similar symptoms, such as ulcerative colitis. Along with taking a full medical history, your doctor may want to conduct a range of medical tests in order to reach a correct diagnosis.

Medical history and physical examination

A full medical history will help your doctor discover whether your symptoms are consistent with inflammatory bowel disease. Your doctor will ask questions about the type and pattern of pain, the appearance and frequency of bowel motions and other related symptoms. A family history of bowel disease such as Crohn's may be discussed.

A physical examination will detect any tenderness in the abdomen, signs of changes in the anal region (fissures or abscesses) and any signs of inflammation.

Blood tests

These will check for infections, inflammation and internal bleeding. Levels of iron, proteins and certain minerals may also be checked.

Stool tests

Stool tests can help decide which type of bowel condition is present and also check for signs of parasites, blood, mucus, or infection.

Endoscopy

This test involves inserting a thin, flexible, lit tube with a camera (endoscope) into parts of the intestines through the mouth (gastroscopy) or via the rectum (colonoscopy). You will be given a mild sedative to help you relax during the procedure and often will be asked to do a bowel preparation prior to the test. The endoscope can take video, photos and tissue samples to provide a highly detailed view of the bowels and locate areas of inflammation.

Colonoscopy procedure. 

Biopsy

A biopsy of the wall of the gut is usually taken during an endoscopy. This sample can then be examined to look at the specific patterns of inflammation. For example, seeing inflammation that involves the full thickness of the bowel wall distinguishes Crohn's disease from other diseases such as ulcerative colitis.

Radiological tests

These tests can be helpful in the diagnosis of Crohn's disease and its complications. They are also often used to monitor your condition and how you are responding to treatment.

Barium testing

Barium testing involves drinking a chalky liquid called barium (a barium swallow) or having the liquid inserted in the rectum (barium enema). This allows structures such as the esophagus, stomach, rectum and sigmoid colon to be clearly seen on X-ray. Strictures, inflammation, fistulas and other disorders may then be seen.

Magnetic resonance imaging

Magnetic resonance imaging (MRI) uses radio waves and magnets to create highly-detailed images of your internal organs. MRI may detect abnormalities and complications of Crohn's disease including abscesses or fistulas in the intestines, as well as changes in the bowel wall related to Crohn's disease.

Computerized tomography

A computerized tomography (CT) scan is a type of highly-specialized X-ray. A dye is ingested, injected or inserted into the rectum. Abnormalities of the intestines related to Crohn's and its complications can show up in a CT scan.

Ultrasound

Ultrasound uses sound waves to create a picture of your internal organs. This will detect abnormalities such as abscesses, which can be complications of Crohn's disease.

Types of treatment

As there is no known cure for Crohn's disease, the main focus of treatment is to reduce the inflammation that causes your symptoms and lessen the risk of complications. In the long term, this can reduce flare-ups and greatly improve your quality of life. In the best possible case, this could lead to you becoming symptom-free for long periods of time (remission).

Lifestyle changes

Being diagnosed with Crohn's disease may make you feel helpless, but making simple changes to your lifestyle and diet may help you to manage your symptoms.

Diet

While there is no diet that has been shown to treat Crohn's disease, some people with Crohn's disease may find certain foods and drinks can make their symptoms worse during a flare-up. It is a good idea to keep a food diary to remind you which foods to avoid, as everyone is different, but some suggestions include:

Smoking

Smoking increases your chances of developing Crohn's disease and tends to make all aspects of the condition worse. If you are a smoker and have Crohn's disease, you are more likely to have more flare-ups and also more likely to need surgery. By quitting smoking, symptoms of the disease can be alleviated.

Stress

Although stress does not actually cause Crohn's disease, it can make your symptoms worse and trigger flare-ups. At times of stress, your stomach empties more slowly, which increases acid production. The movement of food through your intestines may speed up or slow down, often causing cramping or pain. Stress is unavoidable in life, but finding ways to manage it can help. Even small amounts of exercise can reduce stress, ease depression and normalize bowel function. Learning how to relax by doing deep-breathing techniques can greatly reduce your stress levels.

Medication

Medication cannot cure Crohn's disease, but it can help ease many of its symptoms. In the best cases, these drugs can lead to a mostly symptom-free life and long-term relief in-between flare-ups. However, some medications can have side effects, so your doctor can advise you on the best choices for your particular case. Medications include:

Surgery

If lifestyle and diet changes, medications and any other treatments do not give you any relief from symptoms, your doctor may consider surgery. A common surgery for Crohn's disease is bowel resection. Diseased sections of the bowel are removed and the healthy parts sewn together (anastomosis). Surgery can also drain abscesses, close fistulas and widen segments of the bowel that are too narrow (strictureplasty). Unfortunately, the benefits of surgery are often temporary, with symptoms eventually returning. Therefore, surgery is largely reserved for managing the complications of Crohn's disease.

Potential complications

Nutritional deficiencies

The lining of the small intestine is covered in tiny finger-like projections, called villi. These villi absorb nutrients, which then enter your bloodstream. Inflammation or surgery in the small intestine can reduce the amount of nutrients being absorbed, causing malnutrition, fatigue, delayed growth in children and anemia. Medications can also reduce the body's ability to absorb some nutrients. You may need to get vitamin B12 injections on a regular basis.

Fistulas

These are openings between the intestines and other structures in the body such as the bladder, vagina and skin. A fistula may be detected as the cause for recurrent urinary tract infections, or an offensive vaginal discharge. They may heal themselves, but sometimes need surgery.

Toxic megacolon

This is a life-threatening condition in which the colon widens rapidly, accompanied by fever, shock, infection, rapid heart rate and tenderness of the abdomen. Surgery may be needed to remove part of the colon if the condition is severe.

Narrowing of the intestines

Inflammation can cause strictures, narrowing of the space in the intestines, which cause pain, discomfort and bloating. Surgery may be required. Bowel obstruction may result from strictures, usually presenting as severe abdominal pain with the inability to pass either gas or stools.

Prognosis

Crohn's disease is a lifelong condition with symptom-free periods that can vary in length, followed by flare-ups. While recurrence is common, some people can be symptom-free for decades, while others may experience symptoms every few months. Although there is no cure for Crohn's disease, there is a range of medication available, enabling most people to live a normal life. Surgery can sometimes help relieve serious symptoms that are not responding to medications, although it is often not permanently successful.

Prevention

Crohn's disease is a chronic condition with no known prevention or cure, but the severity of signs and symptoms may be reduced in some cases by carefully monitoring your diet, quitting smoking, exercising regularly and reducing your stress levels.

References

  1. CDC - Home Page - Inflammatory Bowel Disease (IBD) - Division of Population Health. Accessed 20 November 2014 from link here
  2. Crohns & Colitis Australia. Accessed 20 November 2014 from link here
  3. Crohns disease and colitis - inflammatory bowel disease - Better Health Channel. - Crohns_disease_and_colitis_-_inflammatory_bowel_disease.pdf. Accessed 20 November 2014 from link here
  4. Crohns disease and ulcerative colitis | Better Health Channel. Accessed 20 November 2014 from link here
  5. Crohns disease: MedlinePlus Medical Encyclopedia. Accessed 20 November 2014 from link here
  6. Crohns disease - National Library of Medicine - PubMed Health. Accessed 20 November 2014 from link here
  7. Crohns disease - NHS Choices. Accessed 20 November 2014 from link here
  8. Edwards A. & Stott N. (1996). The incidence and causes of rectal bleeding. The British Journal of General Practice 46: 625.
  9. Toxic megacolon: MedlinePlus Medical Encyclopedia. Accessed 20 November 2014 from link here
  10. Tumor necrosis factor antagonist mechanisms of action: a comprehens... - PubMed - NCBI. Accessed 20 November 2014 from link here

10 Most frequently asked questions (FAQs)

What is Crohn's disease?
Crohn's disease is a serious chronic inflammatory condition of the lining of the gut that causes abdominal pain, diarrhea, nausea and blood in the stools.
What causes Crohn's disease?
The exact cause of Crohn's disease is unknown, although there are hereditary, autoimmune and lifestyle factors that increase your risk of getting it, such as having family members with the disease, being of Caucasian or Jewish descent and being a smoker. Treatment involves modifying diet and lifestyle and taking medications to control the symptoms. Crohn's disease is not curable, but many people are able to maintain their health and lead normal lives with it. The symptoms come in attacks which can recur every few months or even years.
What are the symptoms of Crohn's disease?
Symptoms of Crohn's disease can include abdominal cramping and pain (especially after eating), frequent diarrhea, blood and mucus in the stools, loss of appetite, weight loss, tiredness and mouth ulcers. However, there are several other conditions that share many of the same symptoms. Your doctor can run some tests to check what is causing your symptoms. You may be referred to see a gastroenterologist (gut specialist) if a problem is suspected.
What diet is best for Crohn's disease?
Every person is different in what foods affect their symptoms of Crohn's disease. Generally during an attack, increase your water intake and avoid fatty, spicy and dairy foods, alcohol, caffeine, carbonated drinks and reduce fiber intake. Taking supplements including vitamin B12 and iron may be of help.
Is Crohn's disease hereditary?
Yes, there appears to be a hereditary component in Crohn's disease. People with a close relative that has the disease are more likely to develop it themselves.
Is there a cure for Crohn's disease?
There is currently no cure for Crohn's disease. However, there are treatments that will reduce the symptoms and damage to the gut. Symptoms can be controlled for long periods of time with careful management.
Is surgery for Crohn's disease necessary?
Surgery for Crohn's disease is usually reserved for severe cases where complications such as fistulas, strictures (narrowing of the gut) or large abscesses have formed. It is used when other therapies have failed.
What's the difference between ulcerative colitis and Crohn's disease?
Ulcerative colitis and Crohn's disease are both chronic inflammatory conditions of the bowel. They share many symptoms such as diarrhea, abdominal pain and blood and mucus in the stools. Ulcerative colitis begins at the rectum and spreads upwards into the large intestine, but not into the small intestine. Crohn's disease mainly affects the small intestine, especially the terminal ileum and is patchy in appearance. It often leads to whole-body symptoms such as weight loss, nausea, fever and lethargy. An endoscopy and blood tests can tell one from the other.
Can Crohn's disease turn into cancer?
It is uncommon for Crohn's disease to result in cancer, particularly if it is being treated effectively.
What treatments are available for Crohn's disease?
The main treatments for Crohn's disease are anti-inflammatory medications, which aim to reduce inflammation in the bowel and prevent complications such as ulcers and strictures, and immunosuppressant medications, which reduce the immune system's impact on the bowel and also reduce inflammation.

Related topics

Ulcerative colitis

Ulcerative colitis is a form of inflammatory bowel disease that mainly affects the large intestine, causing inflammation and ulcers that can lead to bleeding. Treatment depends on the severity of symptoms and the part of the bowel affected. Lifestyle measures can also help reduce flare-ups.

Coeliac disease

Coeliac disease is diagnosed when the body's immune system responds inappropriately to gluten, a protein found in wheat. This results in the inner surface of the small intestine becoming inflamed. A life-long gluten free diet is the main treatment.

Colorectal cancer

Colorectal cancer is the name for cancers that arise in the large intestine or rectum. Also known as colon cancer or colorectal cancer, bowel cancer can interfere with bowel function and spread to other parts of the body, such as the liver and lungs.

Diarrhea

Diarrhea is a common digestive complaint that involves frequent, urgent, and watery bowel movements. Although most cases clear up at home without much treatment, be aware that diarrhea can lead to severe dehydration, especially in children and the elderly.

About this article

Title: Crohn's disease

Author: Karen McCloskey BHSc

First Published: 21 Nov 2014

Last reviewed: 17 Jan 2022

Category: Information on Crohn's disease

Average rating: 4.7 out of 5 (1554 votes)

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