414
U N I T 5
Circulatory Function
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
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
Takayasu arteritis
Granulomatous inflammation of the aorta and its branches; usually
occurs in people younger than 50 years of age
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