What is Crohn’s disease?

What is Crohn's disease

Crohn’s disease Overview

Crohn’s disease is a chronic inflammatory disease of the digestive tract. Symptoms include abdominal pain and diarrhea, sometimes bloody, and weight loss. Crohn’s treatment consists of lifestyle changes, such as exercise and a healthy diet, as well as over-the-counter antidiarrhetics and prescription anti-inflammatory medication.

Symptoms of Crohn’s disease

In some people with Crohn’s disease, only the last segment of the small intestine (ileum) is affected. In others, the disease is confined to the colon (part of the large intestine). The most common areas affected by Crohn’s disease are the last part of the small intestine and the colon.

Signs and symptoms of Crohn’s disease can range from mild to severe. They usually develop gradually, but sometimes will come on suddenly, without warning. You may also have periods of time when you have no signs or symptoms (remission).

When the disease is active, signs and symptoms may include:

  • Diarrhea. Diarrhea is a common problem for people with Crohn’s disease. Intensified intestinal cramping also can contribute to loose stools.
  • Fever and fatigue. Many people with Crohn’s disease experience a low-grade fever, likely due to inflammation or infection. You may also feel tired or have low energy.
  • Abdominal pain and cramping. Inflammation and ulceration can affect the normal movement of contents through your digestive tract and may lead to pain and cramping. You may experience anything from slight discomfort to severe pain, including nausea and vomiting.
  • Blood in your stool. You might notice bright red blood in the toilet bowl or darker blood mixed with your stool. You can also have bleeding you don’t see (occult blood).
  • Mouth sores. You may have ulcers in your mouth similar to canker sores.
  • Reduced appetite and weight loss. Abdominal pain and cramping and the inflammatory reaction in the wall of your bowel can affect both your appetite and your ability to digest and absorb food.
  • Perianal disease. You might have pain or drainage near or around the anus due to inflammation from a tunnel into the skin (fistula).

The Types of Crohn’s Disease

There are several types of Crohn’s disease depending on what part of the GI tract is involved.

  • Ileocolitis affects the ileum and the colon. This is the most common type of Crohn’s disease.
  • Ileitis affects only the ileum.
  • Gastroduodenal Crohn’s disease affects the stomach and the beginning of the small intestine (the duodenum).
  • Jejunoileitis affects the upper half of the small intestine (the jejunum and ileum).
  • Crohn’s (granulomatous) colitis affects the colon only.

What causes Crohn’s disease?

The cause of Crohn’s disease is unknown. Some scientists suspect that infection by certain bacteria, such as strains of mycobacterium, may be the cause of Crohn’s disease. To date, however, there has been no convincing evidence that the disease is caused by infection per se. Crohn’s disease is not contagious. Although diet may affect the symptoms in patients with Crohn’s disease, it is unlikely that diet is responsible for the disease.

Activation of the immune system in the intestines appears to be important in IBD. The immune system is composed of immune cells and the proteins that these immune cells produce. Normally, these cells and proteins defend the body against harmful bacteria, viruses, fungi, and other foreign invaders. Activation of the immune system causes inflammation within the tissues where the activation occurs. (Inflammation is an important mechanism of defense used by the immune system.)

Normally, the immune system is activated only when the body is exposed to harmful invaders. In individuals with IBD, however, the immune system is abnormally and chronically activated in the absence of any known invader. The continued abnormal activation of the immune system results in chronic inflammation and ulceration. The susceptibility to abnormal activation of the immune system is genetically inherited. Thus, first degree relatives (brothers, sisters, children, and parents) of people with IBD are more likely to develop these diseases. Recently a gene called NOD2 has been identified as being associated with Crohn’s disease. This gene is important in determining how the body responds to some bacterial products. Individuals with mutations in this gene are more susceptible to developing Crohn’s disease.

Crohn’s Disease Complications

Complications of Crohn’s disease may be related or unrelated to the inflammation within the intestine. Intestinal complications of Crohn’s disease include obstruction and perforation of the small intestine or colon, abscesses (collections of pus), fistulae, and intestinal bleeding. Massive distention or dilatation of the colon (megacolon) and rupture (perforation) of the intestine are potentially life-threatening complications. Both may require surgery, but, fortunately, these two complications are rare. Recent data suggest that there is an increased risk of cancer of the small intestine and colon in patients with long-standing Crohn’s disease, but studies are conflicting.

Other complications involve the skin, joints, spine, eyes, liver, and bile ducts. Skin involvement includes painful, red, and raised spots on the legs (erythema nodosum) and an ulcerating skin condition generally found around the ankles called pyoderma gangrenosum. Painful eye conditions (uveitis, episcleritis) can cause visual difficulties. Arthritis can cause pain, swelling, and stiffness of the joints of the extremities. Inflammation of the low back (sacroiliac joint arthritis) and of the spine (ankylosing spondylitis) can cause pain and stiffness. Inflammation of the liver (hepatitis) or bile ducts (primary sclerosing cholangitis) also can occur. Sclerosing cholangitis causes narrowing and obstruction of the ducts draining the liver and can lead to yellow skin (jaundice), recurrent bacterial infections, and liver cirrhosis with liver failure. Sclerosing cholangitis with liver failure is one of the reasons for performing a liver transplant. Sclerosing cholangitis often is complicated by the development of cancer of the bile ducts or gallbladder. People who also have cirrhosis are at increased risk of developing liver cancer.

Risk factors of Crohn’s Disease

Risk factors for Crohn’s disease may include:

  • Age. Crohn’s disease can occur at any age, but you’re likely to develop the condition when you’re young. Most people who develop Crohn’s disease are diagnosed before they’re 30 years old.
  • Ethnicity. Although Crohn’s disease can affect any ethnic group, whites and people of Eastern European (Ashkenazi) Jewish descent have the highest risk.
  • Family history. You’re at higher risk if you have a close relative, such as a parent, sibling or child, with the disease. As many as 1 in 5 people with Crohn’s disease has a family member with the disease.
  • Cigarette smoking. Cigarette smoking is the most important controllable risk factor for developing Crohn’s disease. Smoking also leads to more severe disease and a greater risk of having surgery. If you smoke, it’s important to stop.
  • Nonsteroidal anti-inflammatory medications. These include ibuprofen (Advil, Motrin IB, others), naproxen sodium (Aleve, Anaprox), diclofenac sodium (Voltaren, Solaraze) and others. While they do not cause Crohn’s disease, they can lead to inflammation of the bowel that makes Crohn’s disease worse.
  • Where you live. If you live in an urban area or in an industrialized country, you’re more likely to develop Crohn’s disease. This suggests that environmental factors, including a diet high in fat or refined foods, play a role in Crohn’s disease. People living in northern climates also seem to be at greater risk.

What Is the Outlook for Crohn’s Disease?

Crohn’s disease can vary from mild to severe to life threatening. In children, Crohn’s can delay growth and development. In severe cases, it can cause intestinal blockage or ulcers that can tunnel through the intestinal wall into surrounding tissues and organs. These tunnels are called fistulas. They often become infected. Most can be successfully treated with medication, but some require surgery. Crohn’s disease frequently causes loss of appetite and may interfere with absorption of nutrients leading to malnutrition.

If you have been diagnosed with Crohn’s disease, it is important to work with your doctor to develop a treatment plan that works for you. The symptoms of Crohn’s disease may come and go frequently, making it difficult to know if a treatment is working. You should keep track and communicate openly with your doctor. With proper treatment, most people with Crohn’s can live a normal, active life.

How is Crohn’s disease treated?

The symptoms and severity of Crohn’s disease vary among patients. Patients with mild or no symptoms may not need treatment. Patients whose disease is in remission (where symptoms are absent) also may not need treatment.

Crohn’s Disease Medications

There is no medication that can cure Crohn’s disease. Patients with Crohn’s disease typically will experience periods of relapse (worsening of inflammation) followed by periods of remission (lessening of inflammation) lasting months to years. During relapses, symptoms of abdominal pain, diarrhea, and rectal bleeding worsen. During remissions, these symptoms improve. Remissions usually occur because of treatment with medications or surgery, but occasionally they occur spontaneously without any treatment.

Since there is no cure for Crohn’s disease, the goals of treatment are to 1) induce remissions, 2) maintain remissions, 3) minimize side effects of treatment, and 4) improve the quality of life. Treatment of Crohn’s disease and ulcerative colitis with medications is similar though not always identical.

Medications for treating Crohn’s disease include

  1. anti-inflammatory agents such as 5-ASA compounds and corticosteroids,
  2. topical antibiotics, and
  3. immuno-modulators.