ENTEROPATHIC ARTHROPATHIES.

"Enteropathic arthritis" refers to the arthropathies associated with Crohn's disease or ulcerative colitis (see Chapter 135) . These disorders are unified by clinical and histologic gut inflammation, altered intestinal permeability, and the development of an inflammatory peripheral or axial arthritis. Peripheral arthritis is observed in nearly 20% and axial arthritis in 10 to 15% of patients. Peripheral arthropathy more frequently occurs in those with extraintestinal manifestations (e.g., erythema nodosum). Peripheral arthritis affects men and women equally. All age groups are affected, and although the onset of arthritis usually follows established intestinal inflammation in adults, the converse is true in children. Disease onset is sometimes heralded by low-grade fever, painful oral ulceration, ocular manifestations, cutaneous manifestations (e.g., erythema nodosum, pyoderma gangrenosum), or enthesitis. Rarely, a patient may have occult high fever, anemia, or weight loss. Peripheral arthritis is manifested as an inflammatory, non-erosive, asymmetrical oligoarthritis or monarthritis affecting the large joints (i.e., knees, ankles, elbows). Initially, the arthropathy may be migratory and resolve in weeks or months. Peripheral articular activity often parallels gut inflammation. Thus measures to control colitis may prove beneficial for managing peripheral arthritis. With chronicity, peripheral arthritis may be misdiagnosed as seronegative rheumatoid arthritis, particularly when symmetrical joint disease or quiescent gut inflammation is present.

In contrast, with peripheral arthritis, axial disease may precede or coincide with the onset of colitis and is more common in men. Axial arthropathy is clinically and radiographically indistinguishable from ankylosing spondylitis. The course of sacroiliitis and spondylitis is independent of active bowel inflammation. Whereas no association between HLA-B27 and colitic peripheral arthritis has been noted, HLA-B27 is found in 50% of patients with spondylitic colitis. Therefore, inflammatory bowel disease should be considered in the setting of HLA-B27- ankylosing spondylitis.