Microscopic polyangiitis

Microscopic polyangiitis, also called microscopic polyarteritis, is a systemic necrotizing vasculitis that involves small vessels including arterioles, capillaries and venules. Men are affected more often than women are.

The average age at onset of microscopic polyangiitis is about 50 years. This condition is uncommon, and its incidence is unknown.

Typical manifestations include glomerulonephritis, pulmonary haemorrhage or infiltration, musculoskeletal pain (sometimes with synovitis), purpura, peripheral neuropathy and abdominal pain.

Systemic symptoms such as malaise, fatigue and fever are usually present.