Update on systemic necrotizing vasculitis.

The systemic necrotizing vasculitides are classified into vasculitic syndromes on the basis of the pattern of clinical and pathologic involvement. The vasculitides have certain common clinical and laboratory abnormalities. Systemic necrotizing vasculitis is diagnosed on the basis of clinical features, and the vascular nature of the disease is determined by biopsy of involved tissue or angiography. The outcome is dependent on the extent of visceral involvement. Vascular inflammation influences the physiologic features of the vessel and may trigger vasoconstriction. Although glucocorticoids combat the inflammation, they may augment vasoconstriction and platelet aggregation. These effects must be considered in designing a management approach and in evaluating the cause and management of ischemic complications.