[Rheumatoid arthritis--clinical picture and important differential diagnoses]

Rheumatoid Arthritis is a chronic disease of unknown origin. It affects the joints, but also virtually every other organ. Its cause remains still unknown. The prevalence rate is approximately 1% worldwide, with some racial differences. Women are affected three times more often than men. Symmetric swelling of the joints and a substantial morning stiffness are the typical signs of the disease. Most often the wrists, MCP and PIP joints, and the ankle and MTP joints are affected. The arthritis is usually progressive, leading to destructive changes of the affected joints. Neurological symptoms can occur following destruction of the atlantoaxial joint. Diagnosis and classification of the disease follows the 1987 revised American Rheumatism Association criteria, but for practical purposes the approach described by Visser et al. seems more useful, calculating odds ratios for persisting and erosive disease. Effective treatment can start earlier with this approach. Conventional radiology and serum markers, especially the newer antibodies against CCP are important aids in diagnosing rheumatoid arthritis. Diseases to be separated from rheumatoid are other arthritides of autoimmune origin, the cristal arthropathies, vasculitides, septic and parainfectious arthritides, osteoarthritis, and paraneoplastic syndromes.