Historical perspective of vasculitis: polyarteritis nodosa and microscopic polyangiitis.

The original and early case reports of vasculitis provide a historical context and foundation for understanding current concepts of these diseases. These early case reports are valuable as reference points for the current efforts in diagnosing, treating, and classifying vasculitis. In addition, they emphasize the importance of careful clinical observation in these efforts and the essential nature of medical science. Polyarteritis nodosa was the first noninfectious vasculitis to be described and studied in detail. Research on this group of vasculitides has been the cornerstone for understanding the pathophysiology of other forms of idiopathic vasculitis. Historically, most forms of vasculitis described subsequently have been characterized and classified on the basis of features similar to or distinct from polyarteritis.