Systemic Vasculitis - Diagnosis

Diagnosis

A detailed history is important to elicit any recent medications, any risk of hepatitis infection, or any recent diagnosis with a connective tissue disorder such as systemic lupus erythematosus (SLE). A thorough physical exam is needed as usual.

• Lab tests. Basic lab tests may include a CBC, chem-7 (look for creatinine), muscle enzyme, liver function tests, ESR, hepatitis seroloties, urinalysis, CXR, and EKG. Additional, more specific tests include:
  • Antinuclear antibody (ANA) test can detect an underlying connective tissue disorder, especially SLE
  • Complement levels that are low can suggest mixed cryoglobulinemia, hepatitis C infection, and SLE, but not most other vasculitides.
  • Antineutrophil cytoplasmic antibody (ANCA) may highly suggest Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome, or drug-induced vasculitis, but is not diagnostic.

• Electromyography. It is useful if a systemic vasculitis is suspected and neuromuscular symptoms are present.

• Arteriography. Arteriograms are helpful in vasculitis affecting the large and medium vessels but not helpful in small vessel vasculitis. Angiograms of mesenteri or renal arteries in polyarteritis nodosa may show aneurysms, occlusions, and vascular wall abnormalities. Arteriography are not diagnostic in itself if other accessible areas for biopsy are present. However, in Takayasu's arteritis, where the aorta may be involved, it is unlikely a biopsy will be successful and angiography can be diagnostic.

• Tissue biopsy. This is the gold standard of diagnosis when biopsy is taken from the most involved area.