29th January 2024

Background

Epidemiology

Polyarteritis nodosa can occur at any age, with the peak incidence being 45-65 years of age. There is a male predominance of 2:1. 

Aetiology

The cause is largely unknown (idiopathic); however, some cases are associated with active hepatitis B. 

Pathophysiology 

Necrotising vasculitis of medium-sized vessels leads to microaneurysm formation, especially at the bifurcations of vessels. This can cause end-organ damage by aneurysmal rupture and thrombosis of the vessel. PAN most commonly affects the skin, peripheral nerves, muscles, joints, gastrointestinal tract and kidneys.