Nodular polyarteritis scleritis

Nodular polyarteritis (PAN) was first reported by Kussmaul and Maier in 1866. It is a type of necrotizing vasculitis characterized by involving small blood vessels in multiple systems. The lesions are segmental, and they occur at the bifurcation of blood vessels, which can invade adjacent veins and occasionally involve arteries or venules at the distal end of blood vessels. PAN can invade any organ, but the skin, joints, peripheral nerves, gastrointestinal tract, and kidney are the most susceptible. Without treatment, the prognosis is extremely poor. Among untreated patients, the 5-year survival rate was only 12%, while among patients treated systemically with glucocorticoids and immunosuppressants, the 5-year survival rate was 80%.