Microscopic polyangiitis (MPA) is an autoimmune disorder that is characterized by inflammation of the small blood vessels throughout the body. The exact cause of MPA is unknown, but it is believed to be linked to a combination of genetic and environmental factors.
MPA can be difficult to diagnose as it is often confused with other autoimmune disorders. The diagnosis of MPA is based on a combination of clinical signs and symptoms, laboratory tests, and imaging studies. Common signs and symptoms include fever, night sweats, fatigue, joint and muscle pain, weight loss, and rash. Laboratory tests may include complete blood count, kidney and liver function tests, erythrocyte sedimentation rate, and antinuclear antibody tests. Imaging studies such as x-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans may help to identify areas of inflammation.
MPA can be difficult to differentiate from other autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis, and vasculitis.
Treatment of MPA is aimed at reducing inflammation and preventing long-term organ damage. This may include corticosteroids, immunosuppressive drugs, or biologic agents.
The prognosis of MPA is generally good with treatment. However, long-term organ damage from inflammation is possible and can lead to disability.