THE VASCULITIDES
The
vasculitides are a group of systemic disorders with vessel inflammation and
myriad clinical presentations. There are many systems used to categorize them.
The system below is based largely on the size of the vessels involved.
Takayasu
arteritis occurs in older adults (age >50). Initial symptoms may be
non-specific (fatigue) with a variable course to more severe symptoms
(blindness) and involvement of the aortic arch. Microscopically, there is
vessel wall thickening and variable inflammation (from a mononuclear
adventitial infiltrate to medial necrosis with granulomas).
Giant
cell arteritis was formerly called temporal arteritis, but the temporal
arteriesare not always involved. The vertebral and ophthalmic arteries and
aorta are often involved. The typical presentation evolves from nonspecific
symptoms (headache) to more severe symptoms (blindness). Microscopically, there
are inner media granu-lomas in classic cases. Treatment is steroids and
anti-TNF therapy.
Kawasaki
disease presents with mucocutaneous symptoms and cervical lymph
nodeenlargement in children. Involvement of the coronary arteries leads to
cardiovascu-lar sequelae, which can be circumvented with immunoglobulin
therapy. Microscopi-cally, there is transmural vascular inflammation.
Polyarteritis nodosa is
a systemic necrotizing vasculitis occurring most often inyoung adults (M >
F). It has an association with hepatitis B virus. The clinical course is one of
episodic nonspecific symptoms (low-grade fever). Pulmonary involve-ment is
rare; renal artery involvement can be fatal. Immunosuppressive therapy can
achieve remission in most cases.
Small
vessel vasculitides include those that are ANCA (antineutrophil cytoplasmic
antibody)-associated (granulomatosis with polyangiitis, formerly
known as Wegen-er’s granulomatosis; and eosinophilic granulomatosis with
polyangiitis, formerly known as Churg-Strauss syndrome) and those that
are mediated by immune com-plexes (e.g., anti-glomerular basement membrane
disease and IgA vasculitis, also known as Henoch-Schönlein purpura).
Granulomatosis
with polyangiitis typically occurs in middle-aged men;
it is charac-terized by granulomas of the lung and upper respiratory tract,
glomerulonephritis, and a necrotizing granulomatous vasculitis. PR3-ANCAs are
present in most cases.
Eosinophilic
granulomatosis with polyangiitis is associated with asthma,
extravas-cular granulomas (respiratory tract), and a systemic vasculitis that
features eosino-phils; eosinophil counts may be extremely high in peripheral
blood. T lymphocytes and antibodies to MPO (P-ANCA) play a role in the
etiology. There may be increased IgG4 levels. ANCA is present in cases with
glomerulonephritis. The sequential phases are allergic, followed by
eosinophilic and vasculitic. Cardiac involvement may be fatal. Steroids are
therapeutic. Microscopic findings depend upon the organ biopsied: Purpuric leg
lesions show a leukocytoclastic vasculitis; the glomerulo-nephritis tends not to
show eosinophilic infiltrates; the extravascular pulmonary granulomas contain
eosinophils.
Other
small vessel vasculitides include variable vessel vasculitides, e.g.,
Behcet’s disease; single organ vasculitides, e.g.,
CNS vasculitides; and vasculitis associatedwith systemic disease,
e.g., rheumatoid vasculitis.
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