Newest Knowledge of Rheumatoid Arthritis--Symposium: Diagnosis of

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Rheumatoid Arthritis: Medical and Laboratory Aspects. Persselin-Jay-E. Clinical Orthopaedics and Related Research. 1991 Apr. 265. pp 73-82. The diagnosis of rheumatoid arthritis (RA) is largely dependent on the existence of a characteristic pattern of clinical symptoms and signs that must be present for at least six weeks. Early morning joint stiffness and symmetric polyarticular inflammation, particularly in the metacarpophalangeal, proximal interphalangeal, *wrist,* and metatarsophalangeal joints, are typical of the disease. Extraarticular disease, including rheumatoid nodules, is usually associated with severe and well-established arthritis, and occular, pulmonary, cardiac, neurologic, and vasculitic involvement can be a considerable source of morbidity. Serologic testing for rheumatoid factor (RF) is helpful in confirming the diagnosis since 80% of patients are seropositive, but RFs are expressed in many other disease states. Expression of multiple RF isotypes differentiates RA from other populations. Erythrocyte sedimentation rates, C-reactive protein levels, circulating immune complexes, and platelet counts are often elevated in RA and serve as indicators of disease activity.