Medium-sized vessel: polyarteritis nodosa (or small), Kawasaki disease, primary granulomatous CNS vasculitis
Small vessel: ANCA-associated vasculitis (Wegener granulomatosis, Churg- Strauss syndrome, drug-induced, microscopic polyangiitis), immune complex–type vasculitis (Henoch-Schönlein purpura, cryoglobulinemia, rheumatoid vasculitis [or medium], SLE, Sjögren syndrome, Goodpasture syndrome, Behçet syndrome, drug-induced serum sickness), paraneoplastic vasculitis (lymphoproliferative, myeloproliferative, carcinoma), inflammatory bowel disease
Any size vessel (pseudovasculitis): antiphospholipid syndrome, emboli (e.g., myxomas, cholesterol emboli, bacterial or nonbacterial endocarditis), drugs (e.g., amphetamines)
Who Should Be Suspected?
Patients may present with fatigue, weakness, fever, myalgias, arthralgia, headache, abdominal pain, hypertension, nosebleeds, palpable purpura, and/ or mononeuritis.
Coronary artery imaging (angiography, MRI, CT) that reveals a “string-of-pearls” sign sequential proximal coronary aneurysms that is suggestive of a primary or secondary vasculitic process. A focused rheumatic history should be performed in all patients with this angiographic finding.
Laboratory Findings
The gold standard in the diagnosis of most vasculitides is based on pathologic findings in a biopsy of the involved tissue.
Hematology: ESR is increased in 90% of cases, often to very high levels; CRP correlates with disease activity even better than ESR. Normochromic anemia of chronic disease, thrombocytosis, and mild leukocytosis occur in 30–40% of patients; eosinophilia may occur but is not a feature. Leukopenia or thrombocytopenia occurs only during cytotoxic therapy.
Urinalysis: hematuria, proteinuria, and azotemia.
Core laboratory: serum globulins (IgG and IgA) are increased in ≤50% of cases. Serum C3 and C4 complement levels may be increased. RF may be present in low titer. ANA positive in vasculitis secondary to connective tissue disorders. ANCA determination provides valuable information and is highly specific for the diagnosis of small-vessel vasculitides, particularly Wegener granulomatosis.
Imaging studies: arteriogram, MRI, and ultrasound.
Considerations.
