CROHN'S DISEASE (GRANULOMATOUS COLITIS)
Alternative Names: Inflammatory bowel disease - Crohn's disease; Regional enteritis; Ileitis; Granulomatous ileocolitis.
Crohn's disease is an ongoing disorder that causes inflammation of the digestive tract, also referred to as the gastrointestinal (GI) tract. Crohn's disease can affect any area of the GI tract, from the mouth to the anus, but it most commonly affects the lower part of the small intestine, called the ileum. The swelling extends deep into the lining of the affected organ. The swelling can cause pain and can make the intestines empty frequently, resulting in diarrhea.
Crohn's disease is an inflammatory bowel disease, the general name for diseases that cause swelling in the intestines. Because the symptoms of Crohn's disease are similar to other intestinal disorders, such as irritable bowel syndrome and ulcerative colitis, it can be difficult to diagnose. Ulcerative colitis causes inflammation and ulcers in the top layer of the lining of the large intestine. In Crohn's disease, all layers of the intestine may be involved, and normal healthy bowel can be found between sections of diseased bowel.
Crohn's disease affects men and women equally and seems to run in some families. About 20 percent of people with Crohn's disease have a blood relative with some form of inflammatory bowel disease, most often a brother or sister and sometimes a parent or child. Crohn's disease can occur in people of all age groups, but it is more often diagnosed in people between the ages of 20 and 30. People of Jewish heritage have an increased risk of developing Crohn's disease, and African Americans are at decreased risk for developing Crohn's disease.
There are five different types of Crohn's disease:
1. Ileocolitis is the most common form. It affects the lowest part of the small intestine (ileum) and the large intestine (colon).
2. Ileitis affects the ileum.
3. Gastroduodenal Crohn's disease causes inflammation in the stomach and first part of the small intestine, called the duodenum.
4. Jejunoileitis causes spotty patches of inflammation in the top half of the small intestine (jejunum).
5. Crohn's (granulomatous) colitis only affects the large intestine.
The most common complication is blockage of the intestine. Blockage occurs because the disease tends to thicken the intestinal wall with swelling and scar tissue, narrowing the passage. Crohn's disease may also cause sores, or ulcers, that tunnel through the affected area into surrounding tissues, such as the bladder, vagina, or skin. The areas around the anus and rectum are often involved. The tunnels, called fistulas, are a common complication and often become infected. Sometimes fistulas can be treated with medicine, but in some cases they may require surgery. In addition to fistulas, small tears called fissures may develop in the lining of the mucus membrane of the anus.
Nutritional complications are common in Crohn's disease. Deficiencies of proteins, calories, and vitamins are well documented. These deficiencies may be caused by inadequate dietary intake, intestinal loss of protein, or poor absorption, also referred to as malabsorption.
Other complications associated with Crohn's disease include arthritis, skin problems, inflammation in the eyes or mouth, kidney
stones, gallstones, or other diseases of the liver and biliary system. Some of these problems resolve during treatment for disease in the digestive system, but some must be treated separately.
The most common symptoms of Crohn's disease are abdominal pain, often in the lower right area, and diarrhea. Rectal bleeding, weight loss, arthritis, skin problems, and fever may also occur. Bleeding may be serious and persistent, leading to anemia. Children with Crohn's disease may suffer delayed development and stunted growth. The range and severity of symptoms varies
Causes and Risk factors:
While the exact cause of Crohn's disease is unknown, the condition is linked to a problem with the body's immune system response.
Normally, the immune system helps protect the body, but with Crohn's disease the immune system can't tell the difference between good substances and foreign invaders. The result is an overactive immune response that leads to chronic inflammation. This is called an autoimmune disorder.
A person's genes and environmental factors seem to play a role in the development of Crohn's disease. The body may be overreacting to normal bacteria in the intestines.
The inflammation related to Crohn's disease frequently occurs at the end of the small intestine that joins the large intestine, but it may occur in any area of the digestive tract. There can be healthy patches of tissue between diseased areas. The ongoing inflammation causes the intestinal wall to become thick.
The disease may occur at any age, but it usually occurs in people between ages 15 - 35.
Genetic Factors: Although the exact causes of inflammatory bowel disease are not yet known, genetic factors certainly play some role. Between 10 - 20% of people with ulcerative colitis have family members with the disease. Several identified genes and chromosome locations play a role in the development of ulcerative colitis, Crohn's disease, or both. Genetic factors appear to be more important in Crohn's disease, although there is evidence that both forms of inflammatory bowel disease have common genetic defects.
The first important genetic discovery for Crohn's disease was the identification of the genetic variant CARD15 (also called NOD2), which alters the immune system so that it launches an over-reaction in response to bacteria, causing inflammation. However, this genetic factor only affects a small percentage of Crohn's disease cases and is not involved with ulcerative colitis.
In recent years, scientists have made significant genetic research breakthroughs including identifying variants in interleukin-23 receptor (IL23R), which appears to be linked to increased or decreased risk for both Crohn's disease and ulcerative colitis. Other genetic risk factors are also being investigated.
Measles: Some studies have reported that children with IBD may have had more and earlier childhood infections. The measles virus has been of particular interest. According to the U.S. Centers for Disease Control, and many studies, the measles virus does not cause Crohn's or IBD.
Much publicity has centered on whether the vaccine for measles, mumps, and rubella (the MMR vaccine) causes conditions such as autism and Crohn's disease. This theory has been rigorously reviewed and refuted in many well-conducted studies. The evidence clearly indicates that the MMR vaccine does not increase the risk of Crohn's disease, other inflammatory bowel disease, or autism.
Dietary Factors: Inflammatory bowel disease is much more prevalent in industrialized nations and in higher-income groups. However, there is no strong evidence that diet or particular types of food cause Crohn's disease or ulcerative colitis.
There are several risk factors for Crohn's disease.
Age: Crohn's disease can occur at any age, but is most frequently diagnosed in people ages 15 - 35. About 10% of patients are children under age 18.
Gender: Men and women are equally at risk for developing Crohn's disease.
Family History: Crohn's disease tends to run in families, with 20 - 25% of patients having a close relative who also has the disease.
Race and Ethnicity: Crohn's disease is more common among whites, although incidence rates have been increasing among African-Americans as well. It is less common among Latinos and Asians. Jewish people of Ashkenzi (Eastern European) descent are at 4 - 5 times higher risk than the general population.
Smoking: Smoking appears to increase the risk of developing Crohn's disease, and can worsen the course of the disease. (Conversely, smoking appears to decrease the risk of ulcerative colitis. However, because of the hazards of smoking, it should never be used to protect against ulcerative colitis.)
There is no definitive diagnostic test for Crohn's disease. A doctor will diagnose Crohn's disease based on medical history and physical examination, and the results of laboratory, endoscopic, and imaging tests.
Laboratory Tests: Blood tests are used for various purposes, including to determine the presence of anemia. An increased number of white blood cells or elevated levels of inflammatory markers such as C-reactive protein may indicate the presence of inflammation. A stool sample may be taken and examined for blood, infectious organisms, or both.
Flexible Sigmoidoscopy and Colonoscopy: Flexible sigmoidoscopy and colonoscopy are procedures that involve snaking a fiberoptic tube called an endoscope through the rectum to view the lining of the colon. The doctor can also insert instruments through it to remove tissue samples.
Sigmoidoscopy, which is used to examine only the rectum and left (sigmoid) colon, lasts about 10 minutes and is done without sedation. It may be mildly uncomfortable, but it is not painful. Colonoscopy allows a view of the entire colon and requires a sedative, but it is still performed on an outpatient basis. It is important in differentiating between Crohn's disease and ulcerative colitis and in screening for colon cancer.
Upper and Lower Gastrointestinal Barium X-Rays: An upper gastrointestinal barium x-ray may be used if Crohn's disease is suspected in the small intestine. Swallowed barium passes into the small intestine and shows up on an x-ray image, which may reveal inflammation, ulcers, and other abnormalities.
Crohn's disease cannot be cured, but appropriate treatment can help suppress the inflammatory response and manage symptoms. A treatment plan for Crohn's disease includes:
Diet and nutrition.
Diet and Nutrition: Malnutrition is very common in Crohn's disease. Patients with Crohn's disease experience reduced appetite and weight loss. In addition, diarrhea and poor absorption of nutrients can deplete the body of fluid and necessary vitamins and minerals.
Patients should strive to eat a well-balanced healthy diet and focus on getting enough calories, protein, and essential nutrients from a variety of food groups. These include protein sources such as meat, chicken, fish or soy; dairy products such as milk, yogurt, and cheese (if the patient is not lactose-intolerant); and fruits and vegetables.
Depending on your nutritional status, your doctor may recommend that you take a multivitamin or iron supplement. Although other types of dietary supplements, such as probiotics (“healthy bacteria” like lactobacilli) and omega-3 fatty acids, have been investigated for Crohn's disease, there is no conclusive evidence that they are effective in controlling symptoms or preventing disease relapses.
In cases of severe malnutrition, particularly for children, patients may need enteral nutrition. Enteral nutrition uses a feeding tube that is inserted either through the nose and down through the throat or directly through the abdominal wall into the gastrointestinal tract. It is the preferred method for feeding patients with malnutrition who cannot tolerate eating by mouth. Enteral nutrition can be effective for helping maintain remission.
The main medications for Crohn's disease include:
Aminosalicylates (5-ASAs) are anti-inflammatory drugs, which are usually used to treat mild-to-moderate disease. The standard aminosalicylate used for Crohn's disease is sulfazine (Azulfidine).
- Corticosteroids are used to treat moderate-to-severe disease. Common corticosteroids include prednisone (Deltasone) and methylprednisone (Medrol). Budesonide (Entocort) is a newer type of steroid. Because corticosteroids can have severe side effects, they are usually used short-term to induce remission, but NOT for maintenance therapy.
- Immunosuppressives, also called immunomodulators or immune modifiers, block actions in the immune system that are involved with the inflammatory response. Standard immunosuppressives include azathioprine (Imuran, Azasan), 6-mercaptopurine (6-MP), and methotrexate (Rheumatrex). These drugs are used for long-term maintenance therapy and to help decrease corticosteroid dosages.
- Biologic drugs are generally used to treat moderate-to-severe disease. They include infliximab (Remicade), adalimumab (Humira), certolizumab (Cimzia), and natalizumab (Tysabri). Infliximab, adalimumab, and certolizumab target the inflammatory immune factor known as tumor necrosis factor (TNF).
Surgery: Most patients with Crohn's disease eventually require some type of surgery. However, surgery cannot cure Crohn's disease. Problems with fistulas and abscesses may occur after surgeries. New disease usually recurs in other areas of the intestine. Surgery may be helpful for relieving symptoms and to correct intestinal blockage, bowel perforation, fistulas, or bleeding.
Basic types of surgery used for Crohn's disease include:
Strictureplasty: Used to help open up strictures, narrowed areas of intestine.
Resection is used to remove damaged sections of the bowel. The surgeon reattaches the cut ends of the intestine in a procedure called an anastomosis. Repeat resections may be needed if the disease recurs at a different site near the anastomosis.
Colectomy (removal of the colon) or proctocolectomy (removal of the colon and rectum) may be performed in cases of severe Crohn's disease. After a proctocolectomy is completed, the surgeon performs an ileostomy in which the surgeon connects the end of the small intestine (ileum) to a small opening in the abdomen (called a stoma). Patients who have had a proctolectomy and ileostomy need to wear a pouch over the stoma to collect waste. Patients who have had a colectomy can continue to pass stool naturally.
Medicine and medications:
Aminosalicylates (5-ASAs) are anti-inflammatory drugs, which are usually used to treat mild-to-moderate disease. The standard aminosalicylate used for Crohn's disease is sulfazine (Azulfidine). Common side effects of aminosalicylate drugs include: Abdominal pain and cramps, diarrhea, gas, nauseas, hair loss, headache, and dizziness.
Corticosteroids are used to treat moderate-to-severe disease. Common corticosteroids include prednisone (Deltasone) and methylprednisone (Medrol). Budesonide (Entocort) is a newer type of steroid. Because corticosteroids can have severe side effects, they are usually used short-term to induce remission, but NOT for maintenance therapy. Standard steroids can have distressing and sometimes serious long-term side effects, including: Susceptibility to infection, weight gain (particularly increased fatty tissue on the face and upper trunk and back), acne, excess hair growth, high blood pressure (hypertension), weakened bones (osteoporosis), cataracts and glaucoma, menstrual irregularities, upper gastrointestinal ulcers.
Immunosuppressives, also called immunomodulators or immune modifiers, block actions in the immune system that are involved with the inflammatory response. Standard immunosuppressives include azathioprine (Imuran, Azasan), 6-mercaptopurine (6-MP), and methotrexate (Rheumatrex). These drugs are used for long-term maintenance therapy and to help decrease corticosteroid dosages. General side effects of immunosuppressants may include nausea, vomiting, and liver or pancreatic inflammation.
Biologic drugs are generally used to treat moderate-to-severe disease. They include infliximab (Remicade), adalimumab (Humira), certolizumab (Cimzia), and natalizumab (Tysabri). Infliximab, adalimumab, and certolizumab target the inflammatory immune factor known as tumor necrosis factor (TNF).
Other medications: Standard antibiotics include ciprofloxacin (Cipro) and metronidazole (Flagyl). Ciprofloxacin is the antibiotic of choice.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.