Extraintestinal manifestations of inflammatory bowel disease (IBD) are conditions associated with IBD that do not directly involve the intestinal tract. Of course, most of the signs and symptoms of IBD (which comprises Crohn’s disease and ulcerative colitis) do involve the digestive tract. But extraintestinal manifestations of IBD may affect other organs and tissues, including the eyes, skin, and joints. In some instances, such a manifestation may actually be the chief complaint that prompts a patient to seek medical attention.
By definition, IBD is an inflammatory condition. Chronic inflammation involving the tissues lining the gastrointestinal tract is the primary hallmark of Crohn's disease and ulcerative colitis. The two conditions are in part differentiated by the location of the inflammation. Ulcerative colitis involves inflammation of tissues in the colon (lower intestinal tract) and rectum. Crohn's disease involves inflammation that potentially affects the entire digestive tract including both the small and large intestines.
Occasionally, though, inflammation may spill over into other areas of the body, causing what doctors refer to as extraintestinal manifestations (EIMs). In this context, extraintestinal simply means “outside of the intestines.” EIMs may affect the skin, eyes, and joints. Rarely, other conditions—including pancreatitis, oral sores, and certain types of kidney stones, among others—may also occur. These infrequent manifestations are more likely to be associated with Crohn's disease, however, the more common skin and eye disorders affect Crohn's disease and ulcerative colitis patients approximately equal frequency.
Eye manifestations are estimated to affect approximately 10 percent of inflammatory bowel disease (IBD) patients. These disorders may appear before IBD has even been diagnosed. In fact, when a physician encounters these conditions, he or she is advised to consider the possibility of undiagnosed Crohn's disease or ulcerative colitis. Early diagnosis and treatment of “ocular complications” is important, to prevent any loss of vision. Episcleritis and scleritis are characterized by red, inflamed-looking whites of the eye, mild pain, and watery eyes. Of course, “mild pain” is subjective. Some patients may experience itching or burning in the eyes.
While it may resemble the classic “pink eye,” which is usually related to a temporary viral or bacterial infection, episcleritis is somewhat more serious. It affects the thin, outermost layer of tissue between the conjunctiva and the sclera (the connective tissue layer that makes up the white of the eye). While annoying, it does not affect vision, and is usually self-limiting. Episcleritis tends to mirror ongoing intestinal disease activity, and may respond to drug therapy for IBD.
Scleritis, however, is somewhat more serious. The pain can be more intense, there may be sensitivity to light, and significant production of tears. Unlike episcleritis, this condition can progress to the point that vision is affected, possibly even leading to blindness. Scleritis definitely warrants professional attention.
Uveitis is a less common, but more serious condition that involves inflammation of the uvea; the middle layer of the eye. The uvea comprises the iris (the colored portion of the eye), and two other anatomical structures called the choroid and the ciliary body. The most common form of uveitis affects the iris. This is called iritis or anterior uveitis. Disease activity may occur at the same time as flare-ups in the intestines, although it may also occur independently of IBD flares.
Symptoms of uveitis may include redness, pain, sensitivity to light, headaches, floating spots in the field of vision (floaters), diminished vision, and/or a whitish patch towards the lower portion of the iris. Various variations exist, and one or both eyes may be affected. If left untreated, uveitis could progress to cause high pressure in the eye (glaucoma), damage to the optic nerve, clouding of the lens of the eye (cataract), or problems with the retina. All forms of uveitis are potentially serious, and warrant immediate medical attention, as vision loss could occur.
Other Eye Conditions
Other eye conditions may be associated with IBD. These include eye disorders that may be related to side effects of treatment. Systemic glucocorticoids (also called corticosteroids) are common anti-inflammatory drugs prescribed to treat IBD. Their long-term use has been associated with a higher risk of developing cataracts. Other eye disorders include retinal vascular disease, subepithelial keratopathy, etc.
Ocular Extraintestinal Manifestations
Extraintestinal manifestations of IBD that affect the eye(s) are fairly common, and in some instances may arise well before IBD has been diagnosed. Accordingly, it’s important to pay attention to nagging symptoms such as unusually red eyes, floaters, blurry vision, pain, or unusually dry or teary eyes. Rather than ignore these symptoms, seek medical attention.
At best, it could help you and your doctors identify your underlying disease. Once diagnosed, treatments to control your IBD symptoms may also help control the inflammation that is affecting your eyes. You doctor(s) may also prescribe topical treatments for the eyes. At worst, your vision could be at stake.