In Crohn’s disease, this leakage normally occurs very gradually, and the tissues around the intestine have a chance to react and to form a barrier against free leakage of the bacteria into the abdominal cavity. As a result, the bacteria accumulate in a localized area that is effectively walled off. The bacteria grow in the center of this walled-off region, causing a localized infection known as an abscess. An abscess typically contains pus in its center.
Serious Bacterial Infection
When an abscess is not properly treated, it can grow in size. Eventually, the bacteria can spread into the bloodstream and throughout the body, or it can burst into adjacent organs and tissues or into the abdominal cavity, causing the pus to spread throughout the abdomen. Any of these situations can be extremely serious or life threatening.
Fistulas
Fistulas are abnormal channels or tracts joining one part of the intestine to another part of the intestine or to another organ. When an area of the intestine becomes inflamed and ulcerated, the ulcer can penetrate through the full thickness of the intestine wall into an adjacent tissue. This is promoted by the fact that inflamed intestine tends to be “sticky” on its outside surface and will attach to other adjacent segments of intestine, to surrounding organs, or to the inner surface of the abdominal wall.
When a fistula forms between two segments of intestine, there may be no obvious bad consequences, but it is possible that the fistula can result in ingested food bypassing large segments of the intestine. This can cause decreased absorption of nutrients, leading to weight loss and malnutrition. Fistulas can pass from the intestines to adjacent organs, such as the bladder, which, in turn, leads to recurrent urinary infections.
Perianal Fistulas
The most common type of fistula occurs in the area around the anus. These anal fistulas are thought to arise from an infection or inflammation in the glands just below the lining of the anal opening. The infection or inflammation can burrow in various directions through the surrounding tissues and eventually open onto the skin in the area outside the anus. These types of fistulas, also called perianal fistulas or perineal fistulas, can be extremely distressing, and, for some individuals, dominate all other manifestations of their Crohn’s disease.
People with perianal fistulas can have ongoing episodes of pain around the area of the anus, along with swelling and drainage of mucus, pus, blood, and stool. In women, the inflammation and fistulas can extend from the area around the anus to the area of the vagina. When they are particularly severe, the symptoms related to fistulas can interfere with everyday activities, such as sitting, walking, exercising, and riding a bike.
Pain and Shame
When a fistula goes from the intestine to the skin of the abdominal wall or around the anus, intestinal fluid or stool comes out through the opening of the fistula on the skin. In addition to being unsightly, this intestinal fluid makes it difficult to keep the area clean and can be irritating to the surrounding skin.
Because of the location of some fistulas, they can also get in the way of some types of sexual activity. This is not simply a result of the pain that may be associated with a fistula, but also of the potential embarrassment or shame of being “unclean.” If you have these feelings, it is important to realize that you are not alone. Discussing your concerns with your partner will often help soothe some of your fears and concerns about being intimate. Together, you may even be able to come up with sexual activities or positions that you both find pleasurable and that you will not find painful or uncomfortable.
Extra-Intestinal Manifestations
Both Crohn’s disease and ulcerative colitis may be associated with inflammation of tissues outside of the intestinal tract, specifically the joints, eyes, skin, and liver. The extra-intestinal manifestations often occur when the intestinal disease is more active or symptomatic, but they can also occur when the bowels are not giving any trouble at all. Unfortunately, there is no good way to predict who might get these particular complications, nor do we know how to prevent them from occurring. We do know that certain complications have some genetic or inherited basis contributing to their occurrence in IBD.
Complications of IBD Outside the Intestine (Extra-Intestinal Manifestations)
•Joint symptoms (pain, stiffness, swelling)
•Sacroiliitis
•Eye inflammation
•Skin lesions
•Liver disease (primary sclerosing cholangitis)
•Bone disease
Joint Inflammation
Joint symptoms are probably the most common extra-intestinal manifestation of IBD, occurring in up to 30% of patients. The joints that are most commonly affected are the knees, ankles, wrists, and small joints in the fingers (knuckles) and toes. Symptoms of joint involvement or inflammation include pain and stiffness in the joints or, when severe, swelling and redness.
Sacroiliitis
A specific type of arthritis, called sacroiliitis, can occur in the lower back of patients in both Crohn’s disease and ulcerative colitis. This typically presents first with stiffness in the lower back in the mornings and a vague discomfort over the lower back or hips. In a more severe form, called ankylosing spondylitis, the inflammation can extend up the spine, ultimately causing the bones of the spine to fuse together, thereby reducing flexibility and mobility. For ankylosing spondylitis, there is a blood test that can predict who is at risk for developing it, but unfortunately there is really no way to prevent its development.
Compounded Problems
Unfortunately, some of these joint problems, particularly sacroiliitis, tend to persist even when the underlying bowel disease is adequately treated and controlled. To compound the problem, some of the drugs commonly used to treat joint inflammation, such as nonsteroidal anti-inflammatory drugs, may be harmful to the intestinal tract of patients with IBD.
Eye Inflammation
Eye inflammation is a relatively uncommon, but potentially serious, occurrence in IBD. There are several different, though closely related, forms of eye inflammation that can occur (called iritis, uveitis, and episcleritis), which all lead to red and often painful eyes. In some instances, the pain is made worse by bright lights, and there may also be blurring of vision. Any of these symptoms should be assessed promptly by a doctor and treatment started. The usual treatment is medicated eye drops containing steroids, but these should be used only after a proper examination by a qualified practitioner.
Skin Lesions
There are two main types of skin lesions that can be seen occasionally, but not frequently, in patients with IBD: erythema nodosum and pyoderma gangrenosum. Although it isn’t known for certain if early treatment of the skin lesions of IBD result in better outcomes, it is important to be aware of any skin lesion that is particularly painful or enlarging for no apparent reason.
A third type of skin lesion, psoriasis, although not directly caused by IBD, can be seen more frequently in IBD, particularly in patients with Crohn’s disease. Psoriasis typically results in red, raised, scaly, and itchy rashes that can occur just about anywhere on the body. What is interesting is that Crohn’s disease and psoriasis share some genetic factors that increase the risk of both conditions, and the drug treatments of the two inflammatory conditions overlap. Some therapies, such as treatments based on the antitumor necrosis factor (infliximab or adalimumab) or on anti-interleukin-12/23