musculoskeletal and connective tissue disorders
Mixed Connective Tissue Disease (MCTD)
Introduction
Mixed connective tissue disease is an uncommon, specifically defined syndrome characterized by clinical features of systemic lupus erythematosus, systemic sclerosis, and polymyositis with very high titers of circulating antinuclear antibody to a ribonucleoprotein antigen. Hand swelling, Raynaud syndrome, polyarthralgia, inflammatory myopathy, esophageal hypomotility, and interstitial lung disease are common. Diagnosis is by the combination of clinical features, antibodies to ribonucleoprotein, and absence of antibodies specific for other autoimmune diseases. Treatment varies with disease severity and organ involvement but usually includes corticosteroids and additional immunosuppressants. Mixed connective tissue disease (MCTD) occurs worldwide and in all races, with a peak incidence in adolescence and the 20s. About 80% of people who have this disease are women. The cause of MCTD is unknown. In many patients, the disorder evolves into classic Systemic Sclerosis or 