CROHN'S DISEASE

What Is Crohn's Disease? Crohn's disease, along with ulcerative colitis (see the separate article on this condition), is considered a chronic inflammatory bowel disease (IBD). In Crohn's disease there are diffuse, patchy areas of inflammation in the mucosa, the inner surface lining of the intestinal system. Usually, Crohn's disease is chronic with repeated flare-ups and remissions. If the disease becomes chronic, the affected intestinal area becomes rigid and shortened with irreversible structural changes. The disease can involve any portion of the intestinal system with 35% of cases found in the small bowel only, 45% of the case affecting both small and large bowel, and 20% of the cases involving only the large bowel.

What Causes Crohn's Disease? There are no identified causes of Crohn's disease. Evidence suggests that a genetic predisposition may lead to an abnormal immune response to either infection, diet or the environment. However, nothing has been proven conclusively. Crohn's disease is not caused by emotional distress or sensitivity to certain foods or food products, but these factors may trigger symptoms in some people. Cigarette smoking increases the risk of developing Crohn's disease.

What Are Its Signs And Symptoms? Signs and symptoms vary depending on what area of the intestinal system is involved. If the large bowel is involved, patients may experience diarrhea and abdominal pain. Rectal bleeding is less common in Crohn's disease than it is in ulcerative colitis. Patients may also develop fistulas (an abnormal passage that connects one organ to another), fissures (a break or slit in tissue), and abscesses (a local collection of pus), putting them at risk for a severe infection. If both the large and small bowel are involved, patients may develop fistulas and abscesses which can lead to severe infection and fever. If the disease is confined to the small bowel, a patient may experience fatigue, pain after meals, and vomiting. In severe cases there may be signs of dehydration, anemia, fever, and weight loss. Extraintestinal (outside the intestinal system) problems associated with Crohn's disease include arthritis, skin rashes, osteoporosis, kidney stones, thrombophlebitis, inflammation involving the eye, and evidence of liver disease such as cirrhosis. In younger patients delayed growth and sexual maturation can occur. If any of these signs are experienced, see a doctor as soon as possible.

What Are The Complications Of Crohn's Disease? Complications of Crohn's disease include intestinal obstruction caused by scarring from the inflammation. There is also a slight increased risk of cancer of the small bowel and the colon; however, it is not as high as with ulcerative colitis. Intestinal perforation (a tear or hole in the intestine) is a rare but serious complication.

With What Can Crohn's Disease Be Confused? Crohn's disease can be confused with acute infectious colitis and ulcerative colitis, especially if Crohn's disease is limited to the colon. Acute infectious colitis is caused by organisms such as salmonella, shigella, campylobacter, ameobae and sexually transmitted infectious agents such as the causative agent of gonorrhea, the herpes virus and the agent causing genital chlamydial infection. Other causes of severe abdominal pain include acute appendicitis and cancer of the small bowel or colon. In women, pelvic inflammatory disease, an ectopic pregnancy and ovarian cysts or tumours must be excluded.

How is Crohn's Disease Diagnosed? The diagnosis of Crohn's disease is usually accomplished initially by x-ray. Other tests such as barium enema, colonoscopy, endoscopy, biopsy, and computerized tomography (CT) scans are used to further characterize the disease. Ultrasound may be used to distinguish gynecological causes of abdominal pain from Crohn's disease.

How Is Crohn's Disease Treated? No cure is known for Crohn's disease. The initial management usually involve medications such as sulfasalazine and steroids (e.g. prednisone). Both of these are anti-inflammatory agents, which decrease the amount of inflammation in the intestinal tract. Immunosuppressants such as Imuran (azathioprine) are used mainly to replace steroids if the side effects of steroids are not well tolerated. Immunosuppressants decrease the body's immune reaction to foreign substances. These drugs have been shown to partially alleviate the symptoms of Crohn's disease. Flagyl (metronidazole) is an antibiotic which is used to decrease the severity of the disease and helps to improve perianal (near the anus) disease. Surgery is only recommended when there is a poor response to medical treatment and when complications such as fistula formation, obstruction, abscess, perforation and bleeding arise. Unlike in ulcerative colitis, surgery does not cure Crohn's disease. In fact, there is a 50% chance of recurrence of the disease, and a 40% chance that the patient must undergo a second operation.