Microscopic polyangiitis diagnostic criteria

Microscopic polyangiitis (MPA) is a rare autoimmune condition where the body's immune system mistakenly attacks small blood vessels, causing inflammation. To diagnose MPA, doctors look for signs of blood vessel inflammation, such as kidney problems, lung issues, or skin rashes. Blood tests often reveal presence of specific antibodies called ANCA (antineutrophil cytoplasmic antibodies). A kidney or skin biopsy showing inflammation of small blood vessels supports the diagnosis. Importantly, MPA doesn't involve granulomas (clumps of immune cells), helping distinguish it from similar conditions. The diagnosis combines clinical findings, blood tests, and tissue examination to confirm MPA.