Microscopic polyangiitis is a rare autoimmune disease that causes inflammation of small blood vessels, leading to damage in various organs. It primarily affects the kidneys, lungs, and skin, and can result in symptoms such as fatigue, fever, and muscle pain. The exact cause is unknown, but it is associated with the presence of specific antibodies, particularly anti-neutrophil cytoplasmic antibodies (ANCA). Diagnosis typically involves blood tests, imaging studies, and sometimes a biopsy of affected tissues. Treatment often includes medications like corticosteroids and immunosuppressants to reduce inflammation and prevent organ damage. Early detection and management are crucial for improving outcomes in affected individuals.