Vasculitis

Approach to a suspected vasculitis:

· the term “vasculitis” refers to a heterogeneous group of disorders linked by the primary finding of inflammation within blood vessel walls

• common complaints and signs of vasculitis include: fatigue, weakness, fever, arthralgias, abdominal pain, hypertension, renal insufficiency (with an active urine sediment), and neurologic dysfunction
• as the symptoms are nonspecific, the clinical manifestations of vasculitis can be mimicked by a number of other disorders
• some findings that can be somewhat specific for vasculitis include: mononeuritis multiplex (PAN), palpable purpura (HSP and microscopic polyangitis) and a pulmonary/renal syndrome (Wegner’s and anti-GBM)

·  Additional considerations in classification include:

o   patient demographics (age, gender ethnicity)

o   organ tropism

o   presence or absence of granulomatous inflammation

o   presence (or lack) of immune complexes

o   presence of autoantibodies

o   detection of infections associated with some vasculitides

• A general approach includes a detailed history, including any new medications (which can cause a hypersensitivity vasculitis), history of Hep B or C and any previous diagnosis of a disorder known to be associated with a vasculitis (such as SLE)
• Physical exam helps to determine the extent of vascular lesions and possible distribution of affected organs.  Specific findings such as palpable purpura or mononeuritis multiplex are highly suggestive of an underlying vasculitis
• A basic laboratory workup should include: serum creatinine, CK, LFTs, ESR, hepatitis serologies, UA, CXR, and EKG. More specific tests include ANA, ANCA and complement levels. 

Classification of vasculitis:

· vasculitides are classified first by the size of blood vessel involved:

o   small (capillaries and postcapillary venules)

o   medium (muscular arteries and arterioles)

o   large (the aorta and its major branches)

o   there are over 20 forms of systemic vasculitis

· Within small/medium vessel vasculitides, there are 2 main categories:

o   Immune complex deposition: immune complex–mediated tissue injury applies to many forms of vasculitis and overlaps with injuries caused by other immune mechanisms. Examples include:  

§  IgA in Henoch-Schonlein purpura

§  IgG, IgM and complement in mixed cryoglobulinemia

§  HBV surface antigen/antibody complexes in HBV-associated PAN

§  Rheumatoid factor and complement in rheumatoid vasculitis

§  Anti-GBM disease (Goodpasture's disease) is a unique form of immune complex disease in which the immune complexes form in situ rather than in the circulation

o   “Pauci-immune” inflammation: “Pauci-immune” refers not to a lack of immunologic involvement in these disorders, but rather to the absence of significant immunoglobulin or complement deposition within diseased tissues. Many (but not all) patients with pauci-immune forms of vasculitis have ANCA in their serum.  Examples include:

§  Wegener's granulomatosis

§  Microscopic polyangiitis

§  Churg-Strauss syndrome

(Victoria Kelly MD, 12/7/10)