Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss Syndrome)

Updated: Jul 05, 2016
  • Author: Spencer T Lowe, MD; Chief Editor: Herbert S Diamond, MD  more...
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Overview

Background

Eosinophilic granulomatosis with polyangiitis (EGPA)—or, as it was traditionally termed, Churg-Strauss syndrome—is a rare systemic necrotizing vasculitis that affects small-to-medium-sized vessels and is associated with severe asthma and blood and tissue eosinophilia. [1] Like granulomatosis with polyangiitis (Wegener granulomatosis), and the microscopic form of periarteritis (ie, microscopic polyangiitis), EGPA is an antineutrophil cytoplasmic antibody (ANCA)–associated vasculitide. [2, 3, 4, 5]

In 1951, Churg and Strauss first described the syndrome in 13 patients who had asthma, eosinophilia, granulomatous inflammation, necrotizing systemic vasculitis, and necrotizing glomerulonephritis. [3] In 1990, the American College of Rheumatology (ACR) proposed the following six criteria for the diagnosis of Churg-Strauss syndrome [6] :

  • Asthma (wheezing, expiratory rhonchi)
  • Eosinophilia of more than 10% in peripheral blood
  • Paranasal sinusitis
  • Pulmonary infiltrates (may be transient)
  • Histological proof of vasculitis with extravascular eosinophils
  • Mononeuritis multiplex or polyneuropathy

The presence of four or more criteria yields a sensitivity of 85% and a specificity of 99.7%. The 1994 Chapel Hill consensus conference on the classification of vasculitides did not modify the ACR criteria. [7]

The image below depicts transient pulmonary infiltrates.

Transient pulmonary infiltrates in a patient with Transient pulmonary infiltrates in a patient with Churg-Strauss syndrome (CSS).

See Vasculitis: Case Presentations, a Critical Images slideshow, for more information on clinical, histologic and radiographic imaging findings in various forms of vasculitis.

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Pathophysiology

Churg-Strauss syndrome is a granulomatous small-vessel vasculitis. The cause of this allergic angiitis and granulomatosis is unknown. [8] No data have been reported regarding the role of immune complexes or cell-mediated mechanisms in this disease, although autoimmunity is evident with the presence of hypergammaglobulinemia, increased levels of immunoglobulin E (IgE), rheumatoid factor, and ANCA.

A Churg-Strauss syndrome–like syndrome develops as a rare complication in people with asthma who are steroid-dependent and who are treated with leukotriene receptor antagonists (eg, montelukast, zafirlukast) upon reduction in their oral steroid dose. [9] The Churg-Strauss syndrome–like complication is reported in people whose withdrawal of oral steroids is also facilitated by inhaled steroids. This complication is probably related to steroid withdrawal, which unmasks underlying Churg-Strauss syndrome, [10, 11, 12] rather than to the drugs themselves. However, in rare cases, this syndrome has developed when a leukotriene receptor antagonist has been substituted for inhaled steroids without a history of oral steroid withdrawal. [13]

HLA-DRB4 positivity may be a genetic risk factor for the development of Churg-Strauss syndrome and may increase the likelihood of vasculitic manifestations of the disease. [14]

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Epidemiology

Frequency

United States

The incidence of Churg-Strauss syndrome in the United States is 1-3 cases per 100,000 adults per year. [15]

International

The international incidence of Churg-Strauss syndrome is approximately 2.5 cases per 100,000 adults per year.

Mortality/Morbidity

The principal causes of morbidity and mortality in Churg-Strauss syndrome are myocarditis and myocardial infarction secondary to coronary arteritis. [16] With treatment, the 1-year survival rate is 90% and the 5-year survival rate is 62%. [2, 17]

Sex- and Age-related Demographics

Churg-Strauss syndrome is slightly more common in males than in females.The age at onset varies from 15-70 years, with a mean age of approximately 38 years. Churg-Strauss syndrome in pediatric patients is well described, but mostly as case reports. [18] The mean age at diagnosis is around 50 years.

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