Crohn's disease

Definition
Crohn's disease, also known as ileitis or regional enteritis, is a chronic inflammatory condition of the gastrointestinal (GI) tract. The disease typically affects the ileum (the lower part of the small intestine). However, it can develop in any part of the digestive tract, from the mouth to the anus.

Causes/associated factors
Although the causes of Crohn's disease are unknown, there are many theories. One speculates that Crohn's disease is the response of the body's immune system to a virus or bacterium. Others blame genetic predisposition or environmental factors. No compelling evidence suggests specific food allergies as the culprit. New research has found a genetic mutation associated with an increased risk of developing Crohn's disease.
Crohn's disease is most common among Caucasians and members of the Jewish community. It is also more common within some families. It affects men and women equally. Crohn's disease often begins between ages 15 and 25, although it can develop earlier.


Signs/symptoms
Common symptoms of Crohn's disease include:
abdominal pain, often in the lower right part of the body
diarrhea
rectal bleeding
weight loss
fever
foul smelling or bloody stools
joint pain
skin lesions (injuries or wounds)
anemia (a condition marked by a decreased number of red blood cells or hemoglobin, a protein in red blood cells that contains iron)
for children, slowed growth
Crohn's disease involves inflammation that can extend deep into the surrounding tissue, as well as the lymph nodes (the small, round structures located throughout the body that help protect the body from invasion by bacteria or other organisms). The tendency to develop scar tissue, ulcers (open sores on a mucus membrane) and granulomas (tumors or growths that develop around invading microbes when they cannot be completely eliminated by the body's immune system) follows.


Diagnosis
The doctor will ask questions about your medical history and do a physical exam. The doctor may recommend various diagnostic tests, including the following:
stool sample analysis (to rule out infection or malabsorption)
complete blood cell count (a series of blood tests that analyze the cellular components of a blood sample)
traditional X-ray
barium enema (an X-ray of the bowel after drinking a solution of barium sulfate)
upper GI series (an X-ray of the esophagus, the tube that connects the throat and stomach, and upper part of the small intestine)
flexible sigmoidoscopy (examination of the rectum, the end of the large intestine, and the lower part of the colon, the part of the large intestine that extends from the small intestine to the anus)
colonoscopy (a procedure that helps doctors see the inside of the entire colon with a colonoscope, a flexible tube equipped with a camera lens and light)
When the diagnosis remains uncertain after standard lab tests and X-rays, other antibody blood tests may be recommended. For example, antibodies to the yeast Saccharomyces cerevisiae (S. cerevisiae) are found in the bloodstream of 60 to 70 percent of people who have Crohn's disease. Other antibody tests more specific to ulcerative colitis (a chronic disease characterized by diarrhea, inflammation and open sores of the colon) can be compared to further distinguish the diagnosis.


Treatment
There is currently no cure for Crohn's disease. Treatment can help reduce inflammation, improve nutritional status, and alleviate abdominal pain, diarrhea and rectal bleeding. To develop a treatment plan, the doctor will consider the severity of the disease, any complications and prior treatments. Research to find improved treatment options is underway.
Medication therapy
Medication therapy typically includes medications that contain mesalamine, an anti-inflammatory drug that comes in several distinct formulations. Sulfasalazine (brand name Azulfidine) has traditionally been the first medication of choice. In certain people, mesalamine medications containing 5-aminosalicylates or 5-ASA have been shown to be the most effective in controlling inflammation. Plus, they often have fewer adverse reactions overall. If you're allergic to salicylates (a salt of salicylic acid, such as oil of wintergreen), mesalamine is not safe. Your doctor will suggest alternatives.

Some people who have Crohn's disease are given immunosuppressive medications, such as mercaptopurine (Purinethol), azathioprine (Imuran), methotrexate and cyclosporine. These medications hinder the immune response that encourages inflammation in the gastrointestinal tract. Other medications sometimes used to treat Crohn's disease include steroids to control inflammation, antibiotics for infection, antidiarrheal medications for diarrhea, and analgesics for pain.

Infliximab (Remicade) -- the first medication to specifically treat Crohn's disease -- may be prescribed when traditional therapies are unable to control moderate to severe symptoms of Crohn's disease.

The U.S. Food and Drug Administration (FDA) has approved the steroid budesonide (Entocort EC) for the treatment of mild to moderate Crohn's disease. Budesonide is released in the intestine, where it can work directly to decrease inflammation. Because most of the medication is not absorbed into the body, it causes fewer side effects than other steroids that have been used to treat Crohn's disease.

Nutritional supplements
Nutritional supplements can help correct vitamin and mineral deficiencies. During times when the intestines cannot absorb sufficient nourishment or need to rest, intravenous feedings may be given. This process is called hyperalimentation or total parenteral nutrition (TPN).

Surgery
Surgery may be recommended if symptoms do not improve with medical management or complications develop. Recurrences of disease in other segments of the intestines may occur, however, so surgery must be considered carefully. Rarely, Crohn's disease can lead to intestinal failure. In this case, TPN is required to meet a person's nutritional needs. If this therapy is unsuccessful, a small bowel transplant may be recommended.


Complications
Crohn's disease may lead to various complications, including:
intestinal blockage or obstruction
abscess (a collection of pus)
fistulas (abnormal passages from one cavity to another), which may involve the bladder, vagina or skin
hemorrhage (internal or external bleeding caused by damage to a blood vessel)
perianal disease (affecting the area near the anus, the outlet of the rectum)
malabsorption or nutritional deficiencies
arthritis (inflammation of a joint)
skin problems
inflammation in the eyes or mouth
diseases of the liver and biliary tract (the organs and ducts that secrete, store and bring bile -- a fluid made in the liver that helps the body digest fats -- to the duodenum, the part of the small intestine closest to the stomach; mainly the gallbladder, pancreas and liver)
kidney stones
gallstones (stone-like masses in the bile duct or gallbladder; the gallbladder stores bile excreted from the liver and sends it to the small intestine during digestion)

Pregnancy-specific information
Research has shown that Crohn's disease does not usually affect pregnancy if you're well nourished and the condition is well controlled. If you have active Crohn's disease when you become pregnant, however, you may have a higher risk of complications, such as preterm labor. If you have Crohn's disease, it's best to discuss pregnancy with your doctor ahead of time.

Senior-specific information
Again, Crohn's disease is typically diagnosed between ages 15 and 25. Growing older does not increase the risk of developing Crohn's disease.

Prevention
There is no known way to prevent Crohn's disease. Quitting smoking may help, however, as smokers seem to be predisposed to developing the disease. With proper nutrition and medical management, people who have Crohn's disease can often lead normal lives.