What is the initial workup for a patient suspected of having Eosinophilic Granulomatosis with Polyangiitis (EGPA)?

From the Guidelines

The initial workup for a patient suspected of having Eosinophilic Granulomatosis with Polyangiitis (EGPA) should include a comprehensive laboratory evaluation, imaging studies, and possibly tissue biopsy, as recommended by the most recent evidence-based guideline for the diagnosis and management of EGPA 1. The workup should begin with a complete blood count to identify peripheral eosinophilia (typically >1500 cells/μL), which is a hallmark of EGPA.

• Measure inflammatory markers including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), which are usually elevated.
• Test for antineutrophil cytoplasmic antibodies (ANCA), particularly p-ANCA/MPO-ANCA, which are positive in about 30-40% of EGPA patients, as stated in the evidence-based guideline 1.
• Assess renal function with serum creatinine, BUN, and urinalysis to detect potential kidney involvement.
• Pulmonary function tests and chest imaging (X-ray or CT scan) are essential to evaluate lung involvement, which may show transient infiltrates or nodules.
• Cardiac evaluation including ECG, echocardiogram, and possibly cardiac MRI is important as cardiac involvement is a major cause of mortality.
• Nerve conduction studies may be necessary if neurological symptoms are present.
• A tissue biopsy from an affected organ showing eosinophilic infiltration, necrotizing vasculitis, or extravascular granulomas provides definitive diagnosis, although biopsy is not essential to make the diagnosis of EGPA, as stated in the guideline 1. This comprehensive approach is necessary because EGPA is a multisystem disorder with variable presentation, and early diagnosis allows for prompt treatment to prevent organ damage. The diagnostic evaluation of patients with suspected EGPA should always be multidisciplinary, ruling out other eosinophilic and vasculitic disorders and investigating the main disease complications, particularly heart, respiratory, skin, renal, and nervous system involvement, along with ANCA and eosinophilia, as recommended by the guideline 1.

From the Research

Initial Workup for EGPA

The initial workup for a patient suspected of having Eosinophilic Granulomatosis with Polyangiitis (EGPA) involves several steps:

• Patients with asthma, peripheral blood eosinophilia, and damage to other systems should be suspected of having EGPA 2
• A full examination and assessment should be performed, including ANCA testing and biopsy of the affected tissue if feasible 2
• The diagnosis of EGPA should be based on highly suggestive indicative clinical features, laboratory tests, imaging, and objective evidence of vasculitis 2
• Differential diagnosis and multidisciplinary assessment are essential 2

Laboratory Tests and Imaging

• ANCA testing should be performed in all patients suspected of having EGPA 2
• Elevated eosinophils and serum IgE levels are common findings in EGPA patients 3, 4
• Imaging studies, such as high-resolution computed tomography (HRCT) scanning of the chest, may show ground-glass opacities, bronchial wall thickening, and/or bronchial dilatation 4
• Pulmonary function tests may demonstrate an obstructive ventilatory defect 4

Biopsy and Histologic Findings

• Biopsy of the affected tissue may show eosinophil infiltration, vasculitis, and/or granuloma 2, 4
• Histologic findings supporting a diagnosis of EGPA include eosinophil infiltration, vasculitis, and granuloma 4

Disease Severity and Status Assessment

• All patients with EGPA should be assessed for disease severity and status 2
• Disease severity and status should guide treatment decisions, including the use of corticosteroids, immunosuppressants, and biologic agents 2, 5, 6