Microscopic polyangiitis (MPA) is a rare disorder that causes redness and swelling (inflammation) of the small tubes that carry blood to areas of the body - specifically, small arteries (arterioles), capillaries, and small veins (venules). Inflammation of these small tubes can make them narrow, causing poor blood flow to a specific area or organ in the body. Typically, MPA affects the skin, nerves, gastrointestinal tract (esophagus, stomach and intestines), lungs and joints. The symptoms of MPA depend on which of these organ systems are affected. Symptoms may include feeling tired (fatigue), fever, weight loss, rash, joint pain, loss of appetite, cough, shortness of breath, abdominal pain, and numbness.
MPA is rare and can affect a person at any age, but usually affects people in their 40s and 50s. Your doctor can diagnose MPA based on your symptoms, a physical exam, blood tests and images (x-rays, MRI or CT) of the affected area. In some cases, removal and examination of the affected area (biopsy) may be needed to confirm the diagnosis. Some people with MPA will have a positive blood test, known as antineutrophil cytoplasmic antibody (ANCA). However, not everyone with MPA will have a positive ANCA.
Treatment of MPA depends on which tissue or organs are affected and may include medications that control your immune system (immunosuppressive medications) or that treat the inflammation (steroids). The goal of treatment is to stop the inflammation (remission) and to keep it from coming back (maintain remission). However, even after MPA is treated and a person is in remission, symptoms can still return (relapse or flare). If you have been diagnosed with MPA, talk to your doctor to discuss the most current treatment options. Support groups are a good source of additional information.