RHEUMATOID-ARTHRITIS - SEQUENCES

Objective: Rheumatoid arthritis (RA) is an autoimmune disorder of unkn own etiology characterized by symmetric, erosive synovitis and sometim es multisystem involvement. It affects 1% of the adult population and exhibits a chronic fluctuating course which may result in progressive joint destruction, deformity, disability and premature death. We revie w the literature data relative to the peculiar pathologic features of the disease shown by diagnostic imaging techniques. Methods: All our p atients were classified according to the diagnostic criteria of the Am erican Rheumatism Association (1987). Plain radiography remains the di agnostic technique of choice, but ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) are also used. Results: Cli nically articular involvement presents as pain, swelling, stiffness an d motion impairment. The patients with positive rheumatoid factor are > 70% likely to develop joint damage or erosions within 2 years of dis ease onset. Any joint can be involved, but the proximal interphalangea l and metacarpophalangeal joints of the hand and the wrist are prefere ntial sites, as well as the metatarsophalangeal joint of the foot, the knee and the joints of the shoulder, the ankle and the hip. Symmetry is the hallmark of joint involvement. The synovium of bursae and tendo n sheaths is also affected. Soft tissue (subcutaneous nodules), muscle s (weakness and atrophy) and vessels (vasculitis) may also be involved . Systemic involvement may result in Felty's syndrome, metabolic bone disorders (i.e. osteoporosis), Sjogren syndrome and pleuropulmonary ab normalities (pleural effusion, fibrosing alveolitis, constrictive bron chiolitis). The earliest abnormalities consist in synovial proliferati on, soft tissue swelling, and osteoporosis. At a slightly later stage, the inflamed synovial tissue ('pannus') extends across the cartilage surface, leading to chondral erosions and smalt bone erosions at the j oint margin (bare areas). Marginal and central erosions follow in adva nced stages and finally fibrous ankylosis, joint deformities (subluxat ions and dislocations), fractures and fragmentations are typical findi ngs of more advanced RA. Conclusion: RA is a frequent joint disorder w ith a characteristic radiographic picture. Joint involvement patterns are sufficiently common to permit accurate diagnosis, especially when fusiform soft tissue swelling, regional osteoporosis, marginal and cen tral erosions and diffuse loss of interosseous space are present. Conv entional radiography remains the standard imaging technique for joint studies in the patients with suspected RA. US is recommended to diagno se soft tissue involvement (joint effusion). CT is very useful for sho wing abnormal processes in complex joints (sacroiliac and temporomandi bular joints and craniocervical junction) which are difficult to depic t completely with conventional radiography. Magnetic resonance applica tions include the assessment of disease activity: in particular, this technique may be the only tool differentiating synovial fluid and infl ammatory pannus. (C) 1998 Elsevier Science Ireland Ltd. All rights res erved.