Inflammatory leg pain – Spondyloarthropathies
The spondyloarthropathies have common features of chronicity, male predominance, predilection for the spine (sacroiliitis and spondylitis) and occasionally peripheral joints, extra-articular manifestations of rash, iritis, uveitis, conduction defects of the heart, aortic insufficiency, and apical fibrosis of the lungs, and association with HLA-B27. These diseases also share a histological appearance of an inflammatory process with predilection for the enthesis or areas where ligaments, tendons, and joint capsules join bone. The disorders include ankylosing spondylitis, Reiter’s syndrome, psoriatic arthropathy, enteric arthropathy (with inflammatory bowel disease), and juvenile chronic spondyloarthropathy. The most common are ankylosing spondylitis and Reiter’s syndrome. An understanding of these two syndromes and their management can be extrapolated to the less common and related syndromes.
The typical patient with ankylosing spondylitis presents with an insidious his-tory of low back pain and stiffness which can be distinguished from garden variety mechanical low back pain by the history and occasionally by physical examination early in the course. Of patients with ankylosing spondylitis, 20% have involvement of a peripheral joint before their spondylitis. The insidious onset commonly occurs in late adolescence. The most important feature is that symptoms are typically worse after prolonged inactivity (after arising or after prolonged periods of sitting or lying), are improved by physical activity, and are not particularly helped by bed rest. This is different from structural back pain, which is worse with spine use and is relieved by the supine position with the hips and knees flexed. The pattern of hand joint involvement can be useful to differentiate the spondyloarthropathies from other types of inflammatory arthritis. Spondyloarthropathies commonly cause asymmetric diffuse swelling of the digits (so-called sausage digits) or asymmetric joint involvement with distal interphalangeal joint predominance. Dominance of systemic symptoms with fatigue and general stiffness not well localized to the back is an unusual presentation. An occasional patient may present with only iritis and may not develop spondylitis until later.
The typical patient with Reiter’s syndrome is a young male with iritis, urethritis, and skin lesions (balanitis or keratoderma blennorrhagia). In addition, patients may have painless oral ulcers or systemic symptoms. Reiter’s syndrome may be confused with gonococcal arthritis, and one should consider the diagnosis of Reiter’s syndrome in a patient who has persistent urethritis or arthritis and has been treated for a culture-negative gonococcal infection. Reiter’s syndrome that follows dysentery from Yersinia, Shigella, Campylobacter, Salmonella, or Chlamydia is known as postdysenteric Reiter’s syndrome. The typical patient is B27-positive and develops the syndrome within 2 weeks after dysentery.
The natural history of ankylosing spondylitis is good, with most patients being functional, productive, and reasonably comfortable after years of dis-ease. All peripheral joints destined to become involved are usually manifest after 10 years of disease. Patients with early onset or with the hip, knee, shoulder or ankle joints involved are more likely to have worse function later on. The sacroiliitis of ankylosing spondylitis starts in the sacroiliac joints and with time obliterates the joints. It is associated with ascending calcification of the paraspinal ligaments from the lumbar to the cervical spine (bamboo spine). Calcified ligaments can fracture and this is managed as an isolated incident with bed rest and conservative therapy. Spondylitis may also compromise the spinal canal, causing spinal stenosis.
Of patients with ankylosing spondylitis 25% develop iridocyclitis at some point in their course. This is best managed with topical steroids. Patients should be warned about eye involvement and told to report it promptly. Delay in treatment may cause visual loss due to intraocular hypertension, synechiae formation, and occasionally band keratopathy. Patients with spondylitis may also develop pulmonary fibrosis, particularly of the apical segments, aortic insufficiency rarely requiring valve replacement, amyloid, heart conduction defects, meningoencephalitis, and peripheral neuropathy.
The natural history of Reiter’s syndrome is generally good, although some patients can have a chronic recurrent course. Their spondylitis, however, does not appear to be progressive. The principal limiting features in chronic Reiter’s syndrome are the development of peripheral joint disease and, rarely, disabling iritis or balanitis.
The diagnosis of spondyloarthropathies requires a high index of suspicion, based principally on the history of inflammatory back pain and with confirmation by X-ray of the sacroiliac joints. It is not important from a management point of view to distinguish between the various spondyloarthropathies early on, since management is similar. The specific diagnosis will eventually declare itself if other organ systems become involved. X-ray confirmation can be done with a simple posteroanterior view of the pelvis which includes the hips. Additional views of the sacroiliac joints may make the diagnosis in some patients with subtle findings, but are generally not needed. Computed tomography or joint scans have been advocated, but there is tremendous overlap between normal individuals and those with sacroiliitis, and we do not recommend them.
The physical examination is not sensitive in the diagnosis of early spondy-loarthropathy. The sacroiliac joints are quite deep and are inaccessible to direct examination. Mechanical causes of back pain can produce the same physical findings. Measurement of spine mobility should be done, but unless the results are very abnormal, they are not as helpful for making a diagnosis as they are for following the course of an individual patient.
The two most common tests used are Schober’s test and chest expansion. Normal full inspiratory to full expiratory chest expansion should be > 5 cm. Limited chest expansion in ankylosing spondylitis comes from involvement of costovertebral joints, which is usually a late finding. Schober’s test measures the difference in distance between the line connecting the posterior iliac spine and a point 10 cm above in the erect patient and the distance in maximum forward flexion. However, the test can be abnormal in other causes of back pain that result in paraspinal muscle spasm or in patients with hip disease. A normal Schober is > 15 cm.
There are no specific laboratory abnormalities in ankylosing spondylitis or other spondyloarthropathies. The diagnosis of spondyloarthropathy rests mainly on history and X-ray. HLA-B27 testing is marginally useful for diagnosis and does not affect prognosis or management in ankylosing spondylitis. In a patient with post-Yersinia Reiter’s syndrome, the presence of B27 has prognostic value in that it increases the likelihood of developing syndesmo-phytes and sacroiliitis. In a few very problematic cases with a moderate rather than a low or high prior probability of having spondylitis, the test might be helpful. Spondyloarthropathies sometimes result in mild elevations of creatinine phosphokinase (CPK) and alkaline phosphatase. In general, the sedimentation rate does not reflect disease activity in spondyloarthropathies as well as in other inflammatory joint disease.
The management of arthritis or spondylitis centers on drug therapy and physical therapy. The spondyloarthropathies are more responsive to the indolerelated non-steroidal inflammatory drugs, which include indomethacin, tolectin, and phenylbutazone. Phenylbutazone may be the most effective NSAID for ankylosing spondylitis but can cause agranulocytosis. We prefer indomethacin, which is probably the most widely used NSAID in ankylosing spondylitis. A month-long trial of NSAIDs should be undertaken before its effectiveness is judged. When NSAIDs fail, consultation to a rheumatologist should be obtained.
Microbial antigens persist in the synovium and joint fluid of some patients with reactive arthritis and this has prompted studies of antibiotics. These are inconclusive for the majority of Reiter’s patients. A lysine conjugate of tetracy-cline (lymecycline) hastens recovery in post-Chlamydia reactive arthritis but not in post-Yersinia or post-Campylobacter arthritis.
Physical therapy is a traditional component of managing spondylitis, although its effect has only been studied short-term. The rationale for exercise is to maintain the spine in a position of most optimal function when and if fusion occurs. Exercise that can be incorporated into the patient’s lifestyle is most likely to be followed over the long term of the disease. Swimming is an excellent way to extend the spine. Another is to have patients read the newspaper or watch television propped up on their elbows.
Other manifestations of both of these diseases can be treated conservatively. For instance, the conjunctivitis of Reiter’s syndrome may be treated with topical steroids. Uveitis, more common in Reiter’s syndrome, should be promptly evaluated by an ophthalmologist. Oral ulcers usually require no therapy, but if persistent may be treated with local cortisone preparations. Refractory Achilles tendinitis may require prolonged splinting. X-ray therapy has been used successfully in a few anecdotal cases.
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