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.

The association between enteritis and arthritis is supported by the findings of ileocolonoscopic evidence of subclinical gut inflammation in a variety of spondyloarthropathies. Histologic evidence of "acute" colitis (similar to bacterial enteritis) or "chronic" colitis (resembling chronic idiopathic inflammatory bowel disease) is commonly observed. Acute intestinal changes are commonly found in patients with post-dysenteric reactive arthritis, whereas chronic lesions are more typical of ankylosing spondylitis and patients in whom enteropathic arthritis will ultimately be diagnosed.

TREATMENT OF THE SPONDYLOARTHROPATHIES.

Current therapies cannot cure the spondyloarthropathies; therefore, treatment should be aimed at reducing pain and stiffness. An aggressive approach to patient education and joint protection will contribute to the maintenance of optimal function and the patient's sense of well-being and may slow progression to immobility, joint deformity, or axial malalignment. All patients should be counseled regarding a rational program of exercise, rest, physical therapy, and diet and receive vocational counseling. Patients with axial disease should engage in lifelong physical therapy to maintain posture and prevent slow deformity. Once the diagnosis has been established, specific treatment can be initiated. Therapeutic options are largely the same for most of the spondyloarthropathies and as such are considered together (Fig. 287-8) .

NSAIDs.

NSAIDs have replaced the use of salicylates because they have more convenient dosaging and are more efficacious. NSAIDs effectively control the pain, stiffness, and/or joint swelling. Although these agents modify symptoms, they are not thought to retard the underlying inflammatory disease or suppress disease progression. NSAIDs are the mainstay of therapy in ankylosing spondylitis, Reiter's syndrome, reactive arthritis, and psoriatic arthritis. Their use in the enteropathic arthropathies is infrequently hampered by their potential to alter bowel permeability and/or induce exacerbations of colitis.

Although all NSAIDs are potentially useful in the spondyloarthropathies, only a few are of proven benefit and approved by the Fodd and Drug Administration for use in ankylosing spondylitis and/or Reiter's syndrome. These agents include indomethacin, diclofenac, naproxen, sulindac, and phenylbutazone. Of these, indomethacin, especially the sustained-release formula (1 to 2 mg/kg/day) is recommended because of its prolonged duration of effect and anti-inflammatory potency. Other NSAIDs are used according to individual tolerability and efficacy. Phenylbutazone is seldom used and no longer marketed in the