Page 41 - The Vasculitides, Volume 1: General Considerations and Systemic Vasculitis

Overview of Primary and Secondary Vasculitides 17

The category of ANCA-associated vasculitis (AAV) includes granulomatosis with
polyangiitis (GPA) (Wegener granulomatosis [WG type]), eosinophilic granulomatosis with
polyangiitis (EGPA) (Churg-Strauss syndrome [CSS]), and microscopic polyangiitis (MPA)
(microscopic polyarteritis), while vasculitic disorders associated with immune complexes (IC)
includes IgA vasculitis (IgAV) (Henoch-Schönlein purpura [HSP]), cryoglobulinemic
vasculitis (CV), and Hypocomplementemic urticarial vasculitis (HUV) associated with C1q
antibodies. Vasculitis without a predominant vessel size and caliber, respectively from small
to large, involving arteries, veins and capillaries, comprises the category of variable vessel
vasculitis (VVV), characteristic of Behçet disease (BD) and Cogan syndrome.

There is a separate category for vasculitis associated with systemic disease notably for
connective tissue disorders such as rheumatoid arthritis vasculitis (RAV) and systemic lupus
erythematosus (SLE); and another for vasculitis associated with a probable specific etiology,
such as substance abuse and infection designated by the specific vasculitic disorder with a
prefix to denote the causative agent. The category of single organ vasculitis (SOV) involves
arteries or veins of any size in a single organ without features to indicate that it is a limited
expression of a systemic vasculitis that includes primary angiitis of the central nervous
system (CNS) angiitis (PACNS) or primary CNS vasculitis (PCNSV), nonsystemic peripheral
nerve system (PNS) vasculitis or nonsystemic peripheral nerve vasculitis (NSPNV), and
isolated aortitis (IgG4-related disease [RD]). In 2008, the Pediatric Rheumatology European
Society (PRES) and the European League against Rheumatism (EULAR) and the Pediatric
Rheumatology International Trials Organization (PRINTO) reported methodology and overall
clinical, laboratory and radiographic characteristics for several childhood systemic
vasculitides [2] followed by a final validated classification [3] based upon vessel size, similar
to the CHCC nomenclature [1].

Despite disparities in vessel involvement and end-organ damage, it possible to reach a
presumptive diagnosis of primary and secondary vasculitides in the majority of patients based
upon the combination of suggestive symptoms and signs, disease-specific serological studies,
and visceral and neurovascular imaging studies, while awaiting the results tissue
histopathology.

This chapter is an overview of primary and secondary vasculitides in adults and children
for clinicians treating such patients. Five major challenges encountered in clinical practice
will be addressed and emphasized as follows.

First, clinical, pathological, and serological differentiation and diagnosis of the primary
vasculitides including, LVV (GCA, TAK), MVV (PAN, KD), SVV (AAV [MPA, GPA,
EGPA] and IC-mediated types [IgAV and anti-C1q]); and VVV (BD and Cogan syndrome),
all of which share demonstrable histopathological evidence of systemic vasculitis.

Second, recognition of secondary vasculitides associated with an underlying primary
systemic illness, in which some but not all patients will demonstrate evidence of vasculitis
including, CV, RA vasculitis (RAV), and CNS vasculitis associated with SLE, syphilis, Lyme
neuroborreliosis (LNB); bacterial meningitis, tuberculosis (TB), varicella zoster virus (VZV),
and human immunodeficiency virus type 1 (HIV) and acquired immune deficiency syndrome
(AIDS).

Third, the identification of the SOV, PCNSA, NSPNV, and IgG4-RD.
Fourth, a recommended laboratory approach to the diagnosis of vasculitides.
Fifth and last, evidence-based treatment options for each of the vasculitides. Interested
readers are recommended to another in-depth overview [4].

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