musculoskeletal and connective tissue disorders
Eosinophilic Granulomatosis with Polyangiitis (EGPA)
Diagnosis of EGPA
Clinical criteria Routine laboratory tests Echocardiography Biopsy The 2012 Chapel Hill Consensus Conference ( Diagnosis reference ) defined eosinophilic granulomatosis with polyangiitis (EGPA) as an eosinophil-rich and necrotizing granulomatous inflammation involving the respiratory tract with necrotizing vasculitis of small- and medium-sized vessels in association with asthma and eosinophilia. Asthma Eosinophilia of > 10% in peripheral blood Paranasal sinusitis Pulmonary infiltrates, sometimes transient Histologic evidence of vasculitis with extravascular eosinophils Multiple mononeuropathy or polyneuropathy If≥4 criteria are present, sensitivity is 85%, and specificity is 99.7%. Testing aims to establish the diagnosis and the extent of organ involvement and to distinguish EGPA from other eosinophilic disorders (eg, Approach to Parasitic Infections , Blood tests and chest x-rays are done, but results are not diagnostic. Complete blood count with differential is done to check for eosinophilia, which in some patients may be a marker of disease activity. IgE and C-reactive protein levels and erythrocyte sedimentation rate (ESR) are determined periodically to evaluate inflammatory activity. Urinalysis and creatinine are done to screen for renal disease and monitor its severity. Electrolyte levels are measured. Serologic testing is done and detects antineutrophil cytoplasmic autoantibodies (ANCA) in up to 40% of patients; if ANCA is detected, enzyme-linked immunosorbent assay (ELISA) is done to check for specific antibodies. Perinuclear ANCA (p-ANCA) with antibodies against myeloperoxidase is the most common result, but ANCA is not a specific or sensitive test for EGPA. Although used as markers of disease activity, eosinophilia, IgE, ANCA, ESR, and C-reactive protein levels accomplish this and predict flare-ups only with significant limitations. Chest x-ray often shows transient patchy pulmonary infiltrates. A 2D echocardiogram of the heart should be obtained in all patients at baseline and repeated over time if symptoms and/or signs of heart failure develop. Biopsy of the most accessible affected tissue should be done if possible. 1.Jennette JC, Falk RJ, Bacon PA, et al: 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides.Arthritis Rheum65(1):1-11, 2013. doi: 10.1002/art.37715 