Article Sections

Introduction

Vasculitis is characterized by inflammation of blood vessels, leading to end-organ ischemia and dysfunction.  There are ~15 distinct vasculitides, which are categorized by the size of vessels involved (large, medium, small, or variable).

General pathophysiology

Despite diverse presentations, all vasculitides feature systemic inflammation and organ dysfunction.

Systemic inflammation

Patients typically have constitutional symptoms (eg, fever, malaise, anorexia, nonspecific myalgias) and markedly elevated acute phase markers (eg, erythrocyte sedimentation rate, C-reactive protein).

Organ dysfunction

Organ injury in vasculitis is primarily due to ischemia.  In large vessel vasculitis (eg, giant cell arteritis), major arteries are narrowed from infiltration and inflammatory damage to the vessel wall.  Medium vessel vasculitis (eg, Kawasaki disease) can also induce aneurysm formation due to compromised elastic integrity; these can rupture or thrombose, also leading to ischemia.  Small vessel vasculitis (eg, granulomatosis with polyangiitis) causes microcirculatory ischemia as well as capillary extravasation (eg, glomerulonephritis, alveolar hemorrhage, cutaneous purpura).

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