Pediatric forms of vasculitis

Primary vasculitides that affect children are a challenging and complex group of disorders that may involve any system of the body and lead to significant morbidity and mortality. In recent years, there have been significant advances in the field of childhood vasculitides, including the development of classification criteria and outcome assessment. Although some forms of vasculitis occur in both children and adults, considerable differences exist between childhood and adult vasculitides; we review childhood vasculitides, thus highlighting their differences with the adult forms of the disease. We will also discuss monogenic forms of vasculitis, such as deficiency of adenosine deaminase type 2 (DADA2) and haploinsufficiency of A20 (HA20).     

Les vasculites cutanées : aux frontières de l’allergie. Aspects nosologiques et physiopathologiques et prise en charge clinique

The classification of vasculitis is based more on histological criteria than on clinical criteria. Vasculitis is an inflammation of the vessel wall associated to a cell infiltration whose nature is variable according to space and time. Different types of vasculitides are then described: leucocytoclastic vasculitis, granulomatous and necrotizing vasculitis. Most of the vasculitides depend on immunological mechanisms, even though a triggering antigen is rarely found. Immune complex hypersensitivity and delayed-type hypersensitivity are the two main mechanisms involved in vasculitis, except for large vessel vasculitis. We distinguish three types of vasculitis: leukocytoclastic vasculitis (nodular purpura and associated diseases), granulomatous and necrotizing vasculitis (panarteritis nodosa, Wegener’s disease), and large vessel angeitis (Horton’s disease, Kawasaki’s disease and Buerger’s disease). Hypotheses on the pathophysiology of these vasculitides is discussed as well as the treatments.     

Vasculitides of the gastrointestinal tract

Systemic vasculitides, and especially their gastrointestinal manifestations, are a continuous challenge not only for gastroenterologists and rheumatologists but also for every practising physician. Owing to their chameleon-like appearance, overt clinical symptoms of vasculitides may be restricted to distinct parts of the human body including the intestine. In clinical practice, it is therefore essential to search for the systemic disease underlying the gastrointestinal symptoms such as abdominal pain, bleeding, ileus and necrosis in case vasculitis is suspected or likely as a cause for these sequelae. Classification of intestinal vasculitides is also difficult, since most of the criteria currently used have been established by rheumatologists and, in general, biopsies of the affected vessels cannot be obtained. However, there are increasing data that not only facilitate diagnosis but also allow adequate immunosuppressive and anti-inflammatory therapeutic approaches, which will be outlined in detail in this chapter.     

Vasculitis from the pediatric perspective

This article reviews the spectrum of vasculitic illness affecting children. Apart from the relatively common vasculitides (Henoch-Schönlein purpura, Kawasaki disease, and in worldwide terms Takayasu disease) there are a number of important but comparatively rare disorders affecting children. As in adults, there is a considerable degree of overlap between the various vasculitic syndromes in childhood. With modern therapeutic agents, the prognosis for many of the childhood vasculitides has improved; however, in spite of this, there remains a not inconsequential morbidity and mortality. It is anticipated that as our knowledge of the immunopathogenesis of this group of disorders expands, classification and treatment of vasculitis in both children and adults will improve.     

Evolving concepts in classification of systemic vasculitis: where are we and what is the way forward?

The classification of the systemic vasculitides has been controversial for several decades. The Chapel Hill consensus Conference definitions originally developed in 1994, but revised and extended in 2012 are now widely accepted. The American College of Rheumatology (ACR) criteria were first published in 1990, are now generally accepted to be out of date and new criteria are needed. More recently the classical division of the ANCA vasculitides using clinical phenotype has come under scrutiny with evidence from epidemiological, genetic and outcome studies that perhaps these conditions should be classified on the basis of ANCA specificity into PR3‐ANCA positive and MPO‐ANCA positive groups. The traditional distinction between giant cell arteritis and Takayasu arteritis has been questioned and some recent studies of GCA have included patients with only extra‐cranial disease. The Diagnostic and Classification Criteria of Vasculitis study (DCVAS) will provide new validated classification criteria for the systemic vasculitides.     

Systemic vasculitis in adults in northwestern Spain, 1988-1997. Clinical and epidemiologic aspects.

The vasculitides constitute a heterogeneous group of diseases characterized by blood vessel inflammation and necrosis with different but frequently overlapping clinical and pathologic manifestations. The incidence of these conditions is frequently controversial. To further investigate the incidence and clinical manifestations of vasculitides, we reviewed the spectrum of these diseases in an unselected population of adults (age > 20 years) from northwestern Spain during a 10-year period. From January 1988 through December 1997, 267 adults were diagnosed as having vasculitis. The overall average annual incidence rate of vasculitis in the region of Lugo, Spain, between 1988 and 1997 for the population older than 20 years was 141.54/million. Primary vasculitis (115.04/million for the population older than 20 years; 81.3%), especially giant cell arteritis (GCA) was the most common group. Small vessel primary vasculitis (hypersensitivity vasculitis and Henoch-Sch?nlein purpura) was the second most common group. Both GCA and small vessel primary vasculitis had a good outcome. However, although less common, patients with medium and small vessel primary vasculitis, in particular those with polyarteritis nodosa, had a high mortality related to the systemic manifestations of the disease or to the immunosuppressive therapy. Among the group of adults with secondary vasculitis (26.51/million; 18.7%), rheumatic diseases and specifically those occurring in the context of rheumatoid arthritis were the most common group. Patients with secondary vasculitis had clinical or laboratory data that may suggest the presence of an underlying disease. In summary, systemic vasculitides are somewhat more common than previously considered. As in other western countries, GCA constitutes the most common type of vasculitis in northwestern Spain. Better physician awareness may contribute to the progressive increase in the recognition of these conditions.     

Current Concept and Epidemiology of Systemic Vasculitides

Although a new classification algorithm for systemic vasculitides was proposed by Watts et al. and the Chapel Hill Consensus Conference (CHCC) was updated in 2012, there are currently no validated diagnostic criteria for systemic vasculitides. The Diagnostic and Classification Criteria for Vasculitis study (DCVAS) is a global study to develop and improve the diagnostic criteria for systemic vasculitides. The epidemiology of systemic vasculitides differs widely among countries. For example, in the case of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, patients with microscopic polyangiitis (MPA) and with positivity for MPO-ANCA are predominant in Asian countries, whereas patients with granulomatosis with polyangiitis (GPA) and with positivity for PR3-ANCA are predominant in northern Europe and the United States. Interstitial lung disease (ILD) occurs more frequently in Asian patients compared with patients in Europe. The incidence and the prevalence of large-vessel vasculitis also differ significantly. Giant cell arteritis (GCA) occurs frequently in northern Europe, unlike Takayasu arteritis (TAK). The ethnic and regional differences in the incidence, prevalence and clinical characteristics of patients with vasculitis should be recognized when we diagnose and treat patients with vasculitis using criteria, and should also be considered when interpreting the results from clinical studies.     

Classification of vasculitis: From historical controversies to present day pragmatic consensus

The classification of the systemic vasculitides has been controversial for several decades. However, over the past twenty years there have been several major developments, which means that there is pragmatic consensus regarding classification. These include the American College of Rheumatology criteria first published in 1990, and the Chapel Hill Consensus Conference definitions originally promulgated in 1994, but revised and extended in 2012. More recently the classical division of the ANCA vasculitides using clinical phenotype has come under scrutiny with evidence from epidemiological, genetic and outcome studies that perhaps these conditions should be classified on the basis of ANCA specificity into PR3-ANCA positive and MPO-ANCA positive groups. There remains, however, a major need for validated classification and diagnostic criteria, a need which hopefully the DCVAS project will address.     

Classification and diagnostic criteria in systemic vasculitis

Approximately 20 different primary forms of vasculitis are recognized, not all of which have been included in classification schemes or consensus statements regarding nomenclature. A variety of classification schemes have been proposed over the past 50 years, many predicated upon the size of the primary type of vessel involved in a given disease, as well as other considerations that include demographic features, organ tropism, the presence or absence of granulomatous inflammation, the role of immune complexes in pathophysiology and the association of autoantibodies with some forms of vasculitis. All classification schemes to date have had shortcomings owing to the substantial gaps in knowledge about vasculitis, but the American College of Rheumatology criteria for the classification of some forms of vasculitis are useful for the purpose of including patients in research studies. The Chapel Hill Consensus Conference has clarified some existing controversies in nomenclature of the systemic vasculitides. Robust diagnostic criteria for the various forms of vasculitis have, however, remained elusive.     

Systemic vasculitides

The vasculitides are a heterogeneous group of diseases that are characterized by blood vessel inflammation and necrosis. They have a wide spectrum of manifestations due to the involvement of arteries and other vessels of various sizes and locations. Classification criteria are useful in improving our understanding of the epidemiology of these conditions but they are not diagnostic criteria. In recent years a progressive increase in incidence has been reported. Both giant cell arteritis and Wegener's granulomatosis are more common in the Northern hemisphere. Environmental factors have been implicated in the pathogenesis of these syndromes. Recent studies in patients with large and small-sized vasculitides support a genetic influence in disease susceptibility. They have confirmed the association of giant cell arteritis and Henoch-Sch?nlein purpura with HLA-DRB1 alleles. Moreover, the polymorphisms of other genes, such as interleukin-1 receptor antagonist, seem to be implicated in disease severity in patients with cutaneous vasculitis.     

新分类标准对结节性多动脉炎诊断影响的研究初探

随着对抗中性粒细胞胞质抗体（ANCA）相关性血管炎的认识及乙型病毒性肝炎疫苗的广泛接种,结节性多动脉炎（PAN）的诊断发生了很大变化。本研究结合2012年Chapel Hill共识会议（CHCC）对PAN的定义和2007年欧洲药品管理局 （EMA）对中小血管炎分类法则,对2002年1月至2018年12月在北京协和医院住...     

Introduction to, and classification of, the systemic vasculitides.

This overview serves as an introduction to the systemic vasculitides, which are a group of heterogeneous disorders sharing a common pathophysiological mechanism leading to blood vessel inflammation and tissue necrosis. Our lack of understanding of the aetiology for most forms of vasculitis has resulted in the development of a classification system, which is primarily based on vessel size. Such a system assists in the grouping together of similar conditions for the purposes of multi-centre studies. Difficulties arise in classification of the vasculitides due to considerable overlap of clinico-pathological features; for example, microscopic polyangiitis (MPA), Wegener's granulomatosis (WG) and Churg-Strauss syndrome (CSS) may all cause the identical renal lesion of necrotizing glomerulonephritis. The rationale for treatment often depends on the type of vasculitis and on the extent of organ involvement. Treatment may be similar for different types of disease. The lack of validated diagnostic criteria has, however, resulted in the application of classification criteria in their place, and has highlighted the limited usefulness of classification criteria in clinical practice. Classification systems should assist in the determination of therapy and prediction of outcomes, but have many limitations, which are discussed further in this review.     

EULAR/PReS endorsed consensus criteria for the classification of childhood vasculitides

BACKGROUND: There has been a lack of appropriate classification criteria for vasculitis in children. OBJECTIVE: To develop a widely accepted general classification for the vasculitides observed in children and specific and realistic classification criteria for common childhood vasculitides (Henoch-Sch?nlein purpura (HSP), Kawasaki disease (KD), childhood polyarteritis nodosa (PAN), Wegener's granulomatosis (WG), and Takayasu arteritis (TA)). METHODS: The project was divided into two phases: (1) the Delphi technique was used to gather opinions from a wide spectrum of paediatric rheumatologists and nephrologists; (2) a consensus conference using nominal group technique was held. Ten international experts, all paediatricians, met for the consensus conference. Agreement of at least 80% of the participants was defined as consensus. RESULTS: Consensus was reached to base the general working classification for childhood vasculitides on vessel size. The small vessel disease was further subcategorised into "granulomatous" and "non-granulomatous." Final criteria were developed to classify a child as HSP, KD, childhood PAN, WG, or TA, with changes introduced based on paediatric experience. Mandatory criteria were suggested for all diseases except WG. CONCLUSIONS: It is hoped that the suggested criteria will be widely accepted around the world because of the reliable techniques used and the international and multispecialist composition of the expert group involved.     

Do vasculitis categorization systems really matter?

The diagnosis of systemic vasculitides is challenging for many reasons. The etiology and pathogenesis of most vasculitides are unknown or incompletely known. Vasculitides have protean and overlapping clinical and pathologic features. There are conflicting if not contradictory approaches to diagnostic categorization. In spite of these challenges, precise diagnostic categorization is essential for appropriate treatment. This overview reviews the history behind the modern approach to diagnosis of selected vasculitides, including giant cell arteritis, Takayasu arteritis, polyarteritis nodosa, Kawasaki disease, Henoch-Schönlein purpura, cryoglobulinemic vasculitis, Wegener’s granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome. Evidence is provided that the categorization for systemic vasculitis really does matter.     

What is known about the epidemiology of the vasculitides?

The vasculitides are conditions of unknown aetiology. Until recently, relatively little was known about their incidence and prevalence, but there are now increasing data, especially from Europe. These are conditions of the extremes of age. Kawasaki disease occurs predominately in Asian children, with a peak annual incidence of 90/100,000 children aged under 5 years. Henoch-Schonlein purpura has an incidence of 70/100,000 in those aged 4-7 years and is also more common in Asians. Primary systemic vasculitis has a peak incidence 6/100,000 in those aged 65-74 years. Giant cell arteritis is most common in Caucasians aged over 70 years, with an incidence of 53/100,000. Vasculitis has been associated with malignancy, the association being strongest between haematological malignancies and cutaneous vasculitis. There is occasionally a temporal association; failure to respond appropriately to therapy should prompt a search for malignancy. Lesions suspicious of malignancy should be biopsied even if the diagnosis of vasculitis has been histologically proven.     

Pulmonary arterial hypertension complicating adult-onset Still’s disease

The term vasculitis usually evokes a systemic disease with catastrophic outcomes; however, vasculitides may also present in a localized form, with a better prognosis when compared with their systemic counterpart. In order to avoid confusion and facilitate classification, the term single-organ vasculitis (SOV) has been proposed. Remarkably, current criteria for the classification of the vasculitis do not include the SOV term, due in part to the lack of appropriate definitions, since most data come from case series; moreover, the scarce information available is also extremely heterogeneous. This review focuses on the epidemiology, clinical course, prognosis, and suggested treatment of the SOV, with emphasis in the most recent information available.     

A comparison of the performance characteristics of classification criteria for the diagnosis of psoriatic arthritis

OBJECTIVE: To compare the accuracy of published classification criteria for the diagnosis of psoriatic arthritis (PsA) and to see whether data-derived classification criteria would be more accurate. METHODS: Data were abstracted from case-note review and radiographic review of patients identified with PsA or rheumatoid arthritis (RA) from 2 clinical disease registers. Each patient was classified according to 7 criteria sets. The test performance characteristics were compared using conditional logistic regression analysis. In an attempt to overcome the problems of the diagnostic gold standard, latent class analysis also was used to calculate test-performance characteristics. Classification and regression-tree methodology was used to derive new criteria and to indicate the diagnostic importance of particular data items, especially rheumatoid factor (RF). RESULTS: Four hundred ninety-nine patients were identified with RA (n=156) or PsA (n=343). Excluding the criteria of Fournie, which could not be applied in 24% of subjects, 446 cases could be classified by all of the other 6 methods. The most sensitive criteria for the diagnosis of PsA were those of Vasey and Espinoza, McGonagle, and Gladman (99%), whereas the others were significantly less sensitive (between 56% and 94%). The specificity of the criteria was high and statistically similar (between 93% and 99%). The Fournie criteria were the most difficult to use, whereas the Vasey and Espinoza and Moll and Wright criteria were the easiest (98% of subjects were able to be classified). A 2-latent class model found very similar test-performance characteristics. Logistic regression and classification and regression-tree models suggested that negative RF was not necessary for diagnosis in the presence of other characteristic features of PsA. CONCLUSIONS: Apart from the Bennett and European Spondyloarthropathy Study Group criteria, which have inadequate sensitivity, the published classification criteria for PsA have similar test-performance characteristics. These data suggest that the criteria proposed by Vasey and Espinoza, Gladman, or McGonagle are the most accurate and feasible in distinguishing between PsA and RA. Relevance International agreement about classification criteria for PsA will assist the interpretation of clinical and epidemiologic research. However, further prospective studies on unselected patients with and without PsA, including controls with non-rheumatoid inflammatory arthritis, are required to confirm these findings.     

Estimating the incidence of connective tissue diseases and vasculitides in a defined population in Northern Savo area in 2010

Objective of the study was to evaluate the annual incidence and distribution of autoimmune connective tissue diseases and vasculitides during 2010. All units practicing rheumatology in the Northern Savo area, Finland, participated in the study by collecting data on newly diagnosed adult patients with autoimmune connective tissue disease or vasculitis over 1-year period. Seventy-two cases with autoimmune connective tissue disease were identified. The annual incidence rates were as follows: systemic lupus erythematosus 3.4/100,000 (95 % CI 1.4–7.0), idiopathic inflammatory myopathies 1.9 (0.5–5.0), systemic sclerosis 4.4 (2.0–8.3), mixed connective tissue disease 1.0 (0.1–3.5), Sjögren’s syndrome 10.7 (6.7–16.1) and undifferentiated connective tissue disease 13.6 (9.0–19.6). The annual incidence rates among vasculitis category were as follows: antineutrophil cytoplasmic antibody-associated vasculitis 1.5/100,000 (95 % CI 0.3–4.3), central nervous system vasculitis 0.5 (0–2.7) and Henoch-Schönlein purpura 1.5 (0.3–4.3). The annual incidence of giant cell arteritis in the age group of 50 years or older was 7.5/100,000 (95 % CI 3.2–14.8). The longest delay from symptom onset to diagnosis occurred in systemic sclerosis. The incidences of autoimmune connective tissue diseases and vasculitides were comparable with those in published literature. The present study showed female predominance in all connective tissue diseases, excluding idiopathic inflammatory muscle diseases and mean age at onset of disease around 50 years of age. Despite improved diagnostic tools, diagnostic delay is long especially among patients with systemic sclerosis.     

Update on the epidemiology,risk factors,and outcomes of systemic vasculitides

Antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) and giant cell arteritis (GCA) are the most common primary systemic vasculitides of the adult population, while polymyalgia rheumatica (PMR) is a clinical syndrome often associated with GCA.Incidence and prevalence rates of AAV have been increasing in the last decades, whereas those of GCA and PMR have remained stable. The mutual interplay between environmental and genetic risk factors leading to the development of these diseases has been further analyzed in the last years. The role of infectious agents has repeatedly been studied with regard to Staphylococcus aureus, associated with relapse in granulomatosis with polyangiitis, and Herpes zoster, potentially contributing to GCA development.Remission of disease and prevention of disease-related complications are the most important outcomes for all systemic vasculitides. Although these goals are achieved in the majority of patients receiving modern therapies, the prevention of treatment-related complications, especially glucocorticoid side effects, is still an unmet need that is common to AAV, GCA, and PMR.