The aetiology of Mixed Connective Tissue Disease (MCTD) is unknown. It is thought to be an autoimmune disorder in which the body’s immune system mistakenly attacks its own tissues.
The diagnosis of MCTD is based on a combination of laboratory tests and clinical features. The most common laboratory tests used to diagnose MCTD include anti-nuclear antibody (ANA) testing, anti-ribonucleoprotein (RNP) antibody testing, and erythrocyte sedimentation rate (ESR) testing. The clinical features include a combination of symptoms from three other connective tissue diseases: lupus, scleroderma, and polymyositis.
The differential diagnosis for MCTD includes other autoimmune disorders such as systemic lupus erythematosus (SLE) and scleroderma, as well as other inflammatory diseases such as rheumatoid arthritis and vasculitis.
The treatment of MCTD is focused on reducing symptoms, controlling inflammation, and preventing organ damage. Treatment may include medications such as non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, antimalarials, and immunosuppressants.
The prognosis for MCTD is generally good with appropriate treatment. However, some patients may experience flares of the disease or develop complications, such as pulmonary hypertension or interstitial lung disease.