The Relationship of Kawasaki Disease to Other Systemic Vasculitides

Abstract

The vasculitis of Kawasaki disease shares some pathologic attributes with other forms of systemic vasculitis, however, it has a number of distinctive characteristics, including a 1) unique association with mucocutaneous lymph node syndrome although MCLNS may not be completely expressed in all patients, 2) strong predilection for coronary arteries although other arteries may be involved, and 3) pattern of inflammation that shares features with other forms of arteritis but has distinctive characteristics. The three major categories of systemic vasculitis are large vessel vasculitis (chronic granulomatous arteritis), medium-sized vessel vasculitis (necrotizing arteritis), and small vessel vasculitis (necrotizing polyangiitis). Kawasaki disease arteritis and polyarteritis nodosa belong to the medium-sized vessel vasculitis category. There is no problem distinguishing acute Kawasaki disease arteritis from the two major large vessel vasculitides (Takayasu arteritis and giant cell arteritis). Necrotizing arteritis that resembles Kawasaki disease arteritis occurs in polyarteritis nodosa, microscopic polyangiitis, Wegener's granulomatosis, and Churg-Strauss syndrome. Although these vasculitides share some pathologic features with Kawasaki disease arteritis, the overall clinical manifestations and some aspects of the pathologic lesions, allow confident differentiation of Kawasaki disease from these systemic vasculitides. For example, the small vessel vasculitides (e.g., microscopic polyangiitis, Wegener's granulomatosis, and Churg-Strauss syndrome) often have clinical and pathologic evidence for involvement of capillaries (e.g., glomerulonephritis and pulmonary capillaritis) and venules (e.g., dermal leukocytoclastic venulitis) that does not occur with Kawasaki disease. Polyarteritis nodosa has the greatest pathologic similarity to Kawasaki disease arteritis, however, compared to polyarteritis nodosa, the acute arteritic lesions of Kawasaki disease have less neutrophil infiltration, more mononuclear leukocyte infiltration, more edema of the muscularis, and less fibrinoid necrosis. The term infantile polyarteritis nodosa should be abandoned because most patients given this diagnosis actually have Kawasaki disease. In summary, Kawasaki disease and the arteritis of Kawasaki disease are distinct from other forms of systemic vasculitis.