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Circulatory Function

U N I T 5

TABLE 18-3 Classification of theVasculitides Group Examples

Characteristics

Small vessel vasculitis Microscopic polyangiitis

Necrotizing vasculitis with few or no immune deposits affecting medium-sized and small blood vessels, including capillaries, venules, and arterioles; necrotizing glomerulonephritis and involvement of the pulmonary capillaries is common

Wegener granulomatosis Granulomatous inflammation involving the respiratory tract and necrotizing vasculitis affecting capillaries, venules, arterioles, and arteries; necrotizing glomerulonephritis is common, associated with antineutrophil cytoplasmic antibodies (ANCA) Henoch–Schönlein purpura Deposition of IgA-containing immune complexes; inflammation of small blood vessels; form ofType III hypersensitivity Churg-Strauss syndrome Involves arteries of lung and skin; may be generalized, vascular and extravascular; granulomatosis; medium-sized and small vessels

Medium-sized vessel vasculitis

Polyarteritis nodosa

Necrotizing inflammation of medium-sized or small arteries without vasculitis in arteries, capillaries, or venules; usually associated with underlying disease or environmental agents

Kawasaki disease Involves large, medium-sized, and small arteries (frequently the coronaries) and is associated with mucocutaneous lymph node syndrome; usually occurs in small children Thromboangiitis obliterans Segmental, thrombosing, acute, and chronic inflammation of the

medium-sized and small arteries, principally the tibial and radial arteries but sometimes extending to the veins and nerves of the extremities; occurs almost exclusively in men who are heavy smokers Large vessel vasculitis Giant cell (temporal) arteritis Granulomatous inflammation of the aorta and its major branches with

predilection for extracranial vessels of the carotid artery; infiltration of vessel wall with giant cells and mononuclear cells; usually occurs in people older than 50 years of age and is often associated with polymyalgia rheumatica Granulomatous inflammation of the aorta and its branches; usually occurs in people younger than 50 years of age

Takayasu arteritis

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classification system divides the conditions into three groups: (1) small vessel, (2) medium-sized vessel, and (3) large vessel vasculitides (Table 18-3). 1,2 Small vessel refers to small arteries, arterioles, venules, and capillaries; medium vessel refers to small and medium–sized arteries and arterioles; and large vessel refers to the aorta and its major tributaries. The small vessel ANCA-associated vasculitides are involved in a number of different diseases, including Wegener granulomatosis, which is characterized by a triad of acute granulomatous lesions of the upper respiratory tract (ear, nose, sinuses, and throat), necrotizing vascu- litis of the affected small to medium sized vessels of the lungs and upper airways, and renal disease in form of necrotizing glomerulonephritis. 1 Acute Wegener granu- lomatosis is potentially life-threatening and requires initial treatment with corticosteroids combined with a cytotoxic agent. Medium-sized vessel vasculitides produce necro- tizing damage to medium-sized muscular arteries of major organ systems. This group includes polyarteri- tis nodosa, Kawasaki disease (discussed in Chapter 19), and thromboangiitis obliterans (discussed in the section on arterial disease of the extremities). Polyar­ teritis nodosa is an uncommon, acute multisystem

inflammatory disease of small and medium-sized blood vessels of the kidney, liver, intestine, peripheral nerves, skin, and muscle. The usual course of the disease is progressive with various signs and symptoms accord- ing to the pattern of organ involvement. Most cases were fatal before corticosteroid and immunosuppres- sant agents became available for use in treatment of the disorder. 1 Large vessel vasculitides involve large elastic arter- ies; they commonly are called giant cell arterides because they involve infiltration of the vessel wall with giant cells and mononuclear cells. Giant cell (tempo- ral) arteritis, the most common of the large vessel vasculitides, is an acute and chronic inflammation of large to small arteries. It mainly affects arteries of the head—especially the temporal arteries—but may include the vertebral and ophthalmic arteries. About half of persons with the disease have accompanying pain and stiffness of the shoulder and hip (polymyal- gia rheumatica; see Chapter 44). The most common clinical presentation is headache and tenderness over the superficial temporal artery. Diagnosis followed by treatment with corticosteroid drugs is important because involvement of the ophthalmic artery can cause blindness. 1,2