The systemic vasculitides are a group of disorders which are of increasing importance. Many of these conditions are only rarely encountered by general physicians and often present significant diagnostic challenges. Our goal in writing this short book was to provide easily accessible information in a pocket-sized format. We hope we have helped both the g- eral rheumatologist who only encounter these problems occasionally. We have focused on clinical presentation, di- nostic processes, and current management. We hope, the- fore, that we will help our patients with these potentially devastating conditions by improving diagnosis and therapy. Richard A. Watts Ipswich, UK David G. I. Scott Norwich, UK v Contents Part I Introduction 1 Defnitions 3 1 1 General Introduction 3 1 2 Defnitions 4 2 Classifcation and Epidemiology 7 2 1 Introduction 7 2 2 ACR (1990) Criteria 8 2 3 Chapel Hill Consensus Defnitions 9 2 4 Epidemiology 9 2 5 Etiological Factors 10 References 11 3 General Presentation of the Vasculitides 13 3 1 Introduction 13 3 2 Pattern Recognition 13 3 3 Laboratory Investigations 16 3 4 Differential Diagnosis 18 References 19 4 General Principles of Treatment 21 4 1 Treatment 21 4 2 Remission Induction 21 4. 2. 1 Large Vessel Disease ...22 4. 2. 2 Medium Vessel Disease ...22 4. 2. 3 Medium/Small Vessel Vasculitis ...22 4. 2. 4 Small Vessel Vasculitis ...