What is the pathophysiology of polyarteritis nodosa (PAN)?

Updated: Dec 17, 2020
  • Author: Dana Jacobs-Kosmin, MD, FACP; Chief Editor: Herbert S Diamond, MD  more...
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Polyarteritis nodosa (PAN) spares large vessels (the aorta and its major branches), the smallest vessels (capillaries and small arterioles), and the venous system. [7] Vascular lesions affect medium-sized muscular arteries and occur mainly at bifurcations and branch points.

Inflammation may start in the vessel intima and progress to include the entire arterial wall, destroying the internal and external elastic lamina, resulting in fibrinoid necrosis. [7] Aneurysms develop in the weakened vessel, carrying a subsequent risk for rupture and hemorrhage. Thrombi may develop at the site of the lesions. As lesions progress, proliferation of the intima or media may result in obstruction and subsequent tissue ischemia or infarction. [10]

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