Vasculitis

Vasculitis

inflammation of the walls of blood and lymph vessels.

Damaged wall, resulting in either:

Vasculitis in general: there are 20 different types of Vasculitis (plural = vasculitides)

Vessels can be in any organ; isolated in one (generally the skin) or systemic (multiple organs)

Can be caused by:

Immune mediated inflammation
Direct invasion of vascular wall by infectious pathogens
Immunologic cross reactivity with vessel walls induced by infectious or other antigenic agents.

Diagnosis must be accurate because different etiologies require or prohibit immuno-supression.

Relatively common 1:600 though sub categories can be rare.

Severity can range from benign (Behcets, Cogan’s, Kawasaki) to fatal (Wenger’s, Polyarteritis Nodosa)

Diagnosing Vasculitis

Suspect systemic vasculitis if:

Multisytemic disease in absence of sepsis (especially endocarditis)
Drug Toxicity/poisoning (vasoactive drugs: cocaine, amphetamines, phenylephrine-nasal spray)
Coagulopathy; Malignancy: Atrial Myoxoma: atrial tumor embolizes to vascular tree and causes inflammatory response
Multifocal emboli from large vessel aneurysms (cholesterol, nycotic): indwelling line in immunosuppressed patient

If specific classification is not clear, combinations of the following features enhance the probability of Vasculitis:

Biopsy: is the most definitive diagnosis possible: Symptomatic or abnormal sites are highest yield >66%.

Not recommended: Sampling asymptomatic and normal sites (20% specificity) or needle biopsy
May treat in spite of negative biopsy if suspicion is high and result can be explained by course, treatment, or sampling.
If biopsy is impractical (e.g. large vessel disease) then try Angiography (will see medium and large blood vessel stenosis)

Classification and Characteristics of Vasculitis

Small Vessel Vasculitis:

Necrotizing vasculitis affecting Small to medium sized vessels (e.g. capillaries, venules, arterioles and arteries)
Diffuse pulmonary infiltrate possible

Wegener's: necrotizing glomerulonephritis common leading to renal failure, sometimes get upper airway destruction and pulmonary nodules

Churg-Strauss: always accompanied by eosinophilia, asthma, and atopy (allergic reaction without inoculation); occasionally get renal failure or pulmonary nodules

Henoch-Schonlein Purpura: Vasculitis with IgA-dominant immune deposits affecting small b.v. (especially post capillary)

Typically involves skin, gut and glomeruli; associated with arthralgias or arthritis
Benign, but some will die of diffuse pulmonary disease or infarct of the gut
Mean age 5, but adults can get it too.
2/3 of cases preceded by URI by 1-3 weeks

Microscopic Polyarteritis (MPA): Necrotizing vasculitis with few immune deposits affecting small b.v.; Necrotizing arteritis

Medium Sized Vessel Vasculitis

Polyarteritis Nodosa (PAN): Necrotizing inflammation of med/small arteries without vasculitis in arterioles, cap., venules

Large vessel vasculitis

Takayasu Arteritis: Idiopathic systemic disease Þ granulomatous inflammation of aorta and its major branches.

Giant Cell Arteritis: Similar to Takayasu with predilection for temporal, cranial arteries in elderly (>50yo; mean ~70)

Symptoms: unatributable (50%), atypical headache (60-90%), tender temp. a.(40-70%), blindness (12-40%)
Dramatic response to GCS (steroids): 1 week. Relapse is common, toxicity is certain = Constant surveilance