Diagnostic and Therapeutic Challenges of Vasculitis.

Systemic vasculitis can be a challenge to differentiate from other forms of vasculopathy. Because treatment for systemic vasculitis is disparate from that for other forms of vasculopathy, clinicians should strive for high diagnostic certainty. This review article aims to highlight the clinical, radiographic, and histologic clues to distinguish systemic vasculitis from mimics. Vasculitis should be considered in patients with preexisting conditions including autoimmune connective tissue diseases, multisystem manifestations, unexplained ischemic events, unusual radiographic findings, or signs of systemic inflammation. A multidisciplinary approach can be used among rheumatologists, vascular cardiologists, radiologists, and vascular interventionalists to raise diagnostic certainty in cases with large- and/or medium-vessel involvement. Recognition of cardiac manifestations, including myocarditis seen in forms of small-vessel vasculitis (eg, eosinophilic granulomatosis with polyangiitis) or coronary arteritis seen in forms of medium-vessel vasculitis (eg, polyarteritis nodosa and Kawasaki disease) is important owing to the associated mortality. Clinical phenotype, radiographic features, laboratory tests, and histology can help to differentiate vasculitis from noninflammatory vasculopathies and define the etiology of the vasculitis to help guide appropriate treatment. Various modalities of imaging can give clues to aid in diagnosis of vasculitis and can be considered in the context of physician preference and patient comorbidity. While conventional angiography can give important details regarding luminal anatomy and pressure gradients in medium- and large-vessel vasculitis, noninvasive imaging modalities such as computed tomographic angiography, magnetic resonance angiography, color Doppler ultrasound, and positron emission tomography/computed tomography are commonly used for both diagnosis and follow-up. Treatment for systemic vasculitis should be coordinated with an experienced rheumatologist.