Inflammatory leg pain – Systemic rheumatic diseases (RA, SLE, scleroderma, polymyositis, vasculitis)
A number of systemic rheumatic diseases may have synovitis of the lower extremity joints as part of the syndrome or as a presenting symptom. Practically speaking, the arthritis mimics RA and is characteristically symmetric, involving small joints with a predilection for the wrists and fingers in addition to joints of the lower extremity. RA can present with lower extremity joint involvement alone, but not commonly. For the other systemic rheumatic diseases, exclusive lower extemity involvement would be exceedingly rare.
RA is a chronic systemic inflammatory illness and polyarthritis. It typically affects small joints in a symmetrical and additive pattern. It is an illness that may have systemic and extra-articular manifestations such as rheumatoid nodules, vasculitis, neuropathy, scleritis, lung involvement, lymphaden-opathy and pericarditis.
RA affects women two to three times as often as men and increases in prevalence with age up until the seventh decade. One to three percent of the population have RA.
Clinical presentation and course
RA presents in varied ways, and its course ranges from mild illness of brief duration involving only a few joints to a relentless, progressive, destructive polyarthritis with systemic vasculitis. RA may initially present with systemic symptoms such as fatigue, fever, anorexia, and weight loss, and joint symp-toms may manifest themselves only later in the course. About 20% of patients have acute polyarthritis and systemic symptoms as their first manifestation of RA. At the outset, no pattern of clinical presentation or laboratory findings is completely reliable in predicting the course. However, poor function, destructive arthritis, and vasculitic complications are more frequent in patients with sustained high titers of rheumatoid factor, rheumatoid nodules, positive antinuclear antibody at any time in the course, uncontrolled synovitis, and hand–foot joint involvement.
Articular involvement in RA is manifested by pain and swelling. Patients with active RA complain of morning joint stiffness that generally lasts > 30 min, but some may have stiffness throughout the day.
Joint involvement in RA is generally symmetrical, although it may not be absolutely so at any given point. The most commonly involved joints are the small joints of the hand, particularly the metacarpal and proximal inter-phalangeal joints, and the wrists, knees, and feet. A small percentage of patients have pauciarticular or monoarticular disease (which usually involves the knees) for months to years. Any diarthrodal joint with synovium can be involved, including the temporomandibular joints, elbows, shoulders, sternoclavicular joints, hips, ankles, subtalar joints, and cervical spine.
Three patterns of disease are recognized: an intermittent course, a long remission course, and a progressively destructive course. The intermittent course is marked by partial to complete remissions and is generally a mild dis-ease. Another group undergoes a long clinical remission after therapy for RA and may have smoldering signs of inflammation, but has little destructive dis-ease. The third group of patients has progressive destruction of multiple joints with disability with or without extra-articular manifestations.
The diagnosis of RA is made on the basis of the history of swelling, stiffness, gelling, or pain in the small joints of the hand, which is persistent over 6 weeks and may be associated with systemic symptoms such as fatigue, anorexia, and weight loss. The physical examination of actively involved joints shows swelling, warmth, and some pain with range of motion. Early on in the disease, there may be limitation of motion from an increased volume of synovial fluid or pain. Findings such as ulnar deviation, swan neck, boutonniere deformity, and rheumatoid nodules take months or years to develop. Extra-articular manifestations, such as scleritis or vasculitis, constitute a reason to refer the patient to a rheumatologist, whether they occur early or late in the disease.
The laboratory is not helpful in making the diagnosis of RA, particularly in early disease. The rheumatoid factor may be helpful if it is positive, but the number of false-positive rheumatoid factors increases with age. Between 10% and 20% of patients with clinical RA are consistently rheumatoid factor-negative. The sedimentation rate is non-specific and is helpful only for follow-ing therapy when clinical signs are ambiguous. Synovial fluid is inflammatory, but not diagnostic. X-rays are not helpful in early disease but are very useful later to assess structural damage. Six months of active synovitis are usually required before X-ray findings of erosions are manifest.
Patient education is of paramount importance. Patients fear loss of function or chronicity and require support. With good care many options exist for control of the disease. Patients can gain mastery of their condition by becoming active participants in their own care, learning how to monitor the disease, use medications, and maintain function by being as active as possible within their capacities. In assessing function, the physician should assist the patient in identifying functional expectations in the context of career, family, and recreation. The patient should be alert to monitoring his overall well-being, since non-specific symptoms such as fatigue, morning stiffness, and appetite reflect disease activity and may herald a flare.
Current pharmacologic treatment guidelines emphasize use of slow-acting antirheumatic drugs (SAARDs) early in the course of disease to have maximal impact on long-term suffering and disability and to ameliorate progressive immunopathological changes which become irreversible. The SAARDs are medications which can heal bony erosions. They include parenteral gold, oral gold, antimalarials, penicillamine, methotrexate, azathioprine, cyclopho-sphamide, and cyclosporine. Recent novel agents such as etanercept, infliximab, and leflunomide have been approved for the treatment of RA and data suggest that infliximab and methotrexate and etanercept retard structural damage, but their long-term benefits and adverse effect profile are not known. All require close monitoring for toxicity.
Steroids in low doses such as prednisone under 7.5 mg/day and NSAIDs are given for symptomatic relief. There is some preliminary evidence that low-dose steroids may act like SAARDs. NSAIDs do not affect the natural course of the disease. Current NSAIDs have a host of side-effects including NSAID-induced gastropathy. New NSAIDs with highly selective cyclooxgenase-2 (COX-2) inhibition afford protection against gastropathy. Celecoxib and rofe-coxib are the two COX-2-specific inhibitors currently available and more are anticipated. Celecoxib has been approved for the treatment of RA, while rofecoxib has not yet been approved.
Referral to a rheumatologist should be made if (i) extra-articular manifesta-tions are present, (ii) the patient is deteriorating, or (iii) gold, penicillamine, methotrexate or other slow-acting antirheumatic drug therapy or steroids are contemplated.