Could I have irritable bowel disease?

Every weekday, a CNNHealth expert doctor answers a viewer question. On Wednesdays, it's Dr. Otis Brawley, chief medical officer at the American Cancer Society.

Question asked by BH from Milwaukee:

I am a 30-year-old male. I am having episodes of abdominal pain and bloody diarrhea. The doctor says she suspects ulcerative colitis or Crohn's disease and wants to do a colonoscopy. What are these diseases? What else could this be and is it appropriate to do a colonoscopy?

Expert answer:

Dear BH:

There are two major types of inflammatory bowel disease, or IBD: ulcerative colitis and Crohn's disease. It is estimated that inflammatory bowel disease affects about 500,000 Americans. Most IBD is diagnosed between ages 15 and 40 although some is diagnosed as late as age 80

The course of IBD typically consists of intermittent flare-ups of the disease alternating with sometimes long periods without symptoms.

Ulcerative colitis involves inflammation of a part of the colon and rectum. Patients can have episodes of abdominal pain, gaslike pains, bloody diarrhea, even fever during a flare, which can last for weeks or months. In its more severe form patients with UC can also have arthritis, liver problems (sclerosing cholangitis), certain skin rashes and eye problems (uveitis)

The abdominal complaints of mild ulcerative colitis are often confused with gluten allergy (celiac sprue). Other things that can be confused with IBD include amoebic, parasitic and bacterial bowel infections. Of these, Salmonella and Clostridium Difficile are most common. Salmonella can be caught from eating poorly stored or undercooked meats. Clostridium Difficile is a disease that is getting more common. It is caused by use of antibiotics. Most amoebic and parasitic infections are due to drinking contaminated water.

Crohn's disease is an inflammation that can occur anywhere in the GI tract from the mouth to the anus. When in the colon, symptoms can be similar to ulcerative colitis. Crohn's disease can cause fibrosis or scarring of the GI tract, leading to bowel obstruction or blockage, pain and fistulae. A fistula is a hole in the bowel through which bowel fluid and gas can leak. A fistula can track to other organs. Some patients with severe Crohn's can have a fistula track from the rectum to the bladder or rectum to vagina.

Crohn's disease can skip parts of bowel and a patient can have episodes of inflammation in several areas at one time. Most patients do have some small bowel involvement and about a third have disease only in the small bowel. This is often referred to as Crohn's ileitis.

Both diseases are most commonly diagnosed when a physician suspects the disease and a scoping procedure of the GI tract is performed with a fiber-optic scope. Upper endoscopy is done to investigate disease of the esophagus, stomach and small intestine. Colonoscopy is done to assess the colon, and on occasion, the distal ileum, which is the end of the small bowel. The physician can see areas of inflammation or scarring and may do a culture to diagnose infection as well as a biopsy of abnormal areas through the scope. A pathologist can confirm the diagnosis of Crohn's or ulcerative colitis with microscopic examination of the biopsy.

The causes of these diseases are unknown. Both are more common in Jews compared with non-Jews and in white Europeans compared with all other groups. The diseases do tend to run in families. In some studies, 10% to 25% of IBD patients have a first-degree relative with one of the diseases. It is not uncommon for a patient with Crohn's to have a relative with ulcerative colitis or vice versa.

For unknown reasons, there are higher rates of UC in developed countries versus developing countries. Rates are higher in the northern latitudes versus the equatorial climates.

No one knows the cause of the inflammatory bowel diseases. Older literature suggested there was a psychiatric component to these diseases. Today, it is known that stress or getting upset can cause an exacerbation of the disease, but a psychiatric illness is not believed associated with an underlying of the disease.

Interestingly, smoking appears to decrease the risk of UC and increase the risk of Crohn's disease.

While many have tried to link elements in diet as a cause of IBD, data are by no means definite. Most believe that a Western diet of processed, fried and sugary food does increase risk of IBD. It is possible that IBD is an immunologic response to foods. There is some speculation that hypersensitivity to cow's milk in infancy may cause IBD. This has been fueled by some studies to show that IBD patients were less likely to be breast fed as babies.

Patients with IBD are prone to malnutrition due to malabsorption. Children with the disease can have stunted growth.

Treatment includes attention to nutrition. There are medical therapies for the inflammatory bowel diseases and some patients with severe disease will have to have bowel resections. Patients with IBD, and especially ulcerative colitis, affecting the colon and rectum are at higher than normal risk of cancer of the colon or rectum. It is customary that UC patients get regular colonoscopy to detect malignancy. There are gastroenterologists who specialize in the treatment of this disease.