Case Report: Could Myocarditis + Shortness of Breath = EGPA?

The 2012 Revised International Chapel Hill Consensus Conference nomenclature of vasculitides, note EGPA is an “eosinophil-rich and necrotizing granulomatous inflammation often involving the respiratory tract, and necrotizing vasculitis predominantly affecting small to medium vessels with associated asthma and eosinophilia.”⁷

The recently published MIRRA Study (Investigating Mepolizumab in the Treatment of EGPA) defined EGPA as the presence of asthma and eosinophilia (>1.0×10^9/L and/or >10% of leukocytes) plus at least two of the following features: a biopsy showing histopathological evidence of eosinophilic vasculitis; perivascular eosinophilic infiltration; eosinophil-rich granulomatous inflammation; neuropathy (mono- or poly- with motor deficit or nerve conduction abnormality); pulmonary infiltrates (non-fixed); sino-nasal abnormality; cardiomyopathy (established by echo or MRI); glomerulonephritis (hematuria, red cell casts, proteinuria); alveolar hemorrhage (via bronchoalveolar lavage); palpable purpura; or being ANCA positive (myeloperoxidase or proteinase 3).⁸

No laboratory tests specific for EGPA exist, although eosinophilia is characteristic. ANCA are found in roughly 30–60% of EGPA patients.⁹ Our patient was ANCA negative. Myocarditis (as well as alveolar hemorrhage) more typically appears in ANCA-negative EGPA, as demonstrated in our case.¹⁰

The majority of ANCA-positive EGPA patients (70–75%) have antibodies directed against myeloperoxidase (MPO) with a perinuclear staining pattern (P-ANCA).¹¹ Labs may also reveal leukocytosis, reactive thrombocytosis and a positive rheumatoid factor, all of which appeared in our patient.¹² Imaging studies in EGPA can reveal transient and patchy opacities in up to 75% of patients, which was observed in our patient.¹³

Clinicians must understand the systemic nature of EGPA. Our patient had suspected multi-organ involvement, including upper airway/nasal, lower airway/pulmonary, gastrointestinal, cardiovascular and neurologic systems. Cardiac involvement is one of the more serious manifestations of EGPA, because clinical manifestations can include signs of heart failure, myocarditis, pericarditis and cardiac rhythm abnormalities.^14,15

The main diseases to consider in the differential diagnosis of EGPA include hypereosinophilic syndrome, aspirin-exacerbated respiratory disease, the eosinophilic pneumonias and allergic bronchopulmonary aspergillosis, as well as the other two ANCA-associated vasculitides (i.e., granulomatosis with polyangiitis and microscopic polyangiitis). Treatment for patients with EGPA and evidence of systemic vasculitis includes prednisone (0.5–1 mg/kg/day).¹⁶ Cyclophosphamide is typically used in combination with steroids for severe, multi-organ disease.¹⁷ Maintenance and glucocorticoid sparing therapy includes azathioprine, methotrexate, leflunomide and a humanized monoclonal antibody to interleukin 5 (mepolizumab).¹⁸

Our case demonstrates a unique presentation of EGPA presenting with myocarditis before diagnosis. Although EGPA remains rare, consider it in patients presenting with myopericarditis. This may aid in early diagnosis and prompt immunosuppressive therapy to prevent long-term complications.