Myocarditis as the first manifestation of eosinophilic granulomatosis with polyangiitis

Introduction. Myocarditis is a common diagnosis, but its etiology often remains unknown as it requires extensive diagnostic work. Eosinophilic granulomatosis with polyangiitis (EGPA) or Churg-Strauss syndrome is a very rare systemic disease, which is not easy to diagnose. Myocarditis in EGPA is not common and it usually occurs in the late stages of the disease. Case report. A 22-year-old man was admitted as acute coronary syndrome (ACS). Coronary angiography was performed and excluded stenosis of epicardial coronary arteries. The working diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA) was established. Then we found inflammatory syndrome, eosinophilia and a lot of systemic symptoms and signs. We managed to establish the diagnosis of myopericarditis by cardiac magnetic resonance imaging (MRI). The diagnostic workout included extensive laboratory tests, which ruled out infectious agents. Then, immunological tests, a computed tomography (CT) scan of the chest, and a biopsy of the bone marrow, nasal mucosa, and skin were performed. The cause of myocarditis - EGPA, was found only after the histopathological finding of the skin biopsy, which enabled adequate immunosuppressive therapy. Conclusion. The accurate diagnosis was crucial for the correct-causal treatment of the patient, especially since he needs life-long immunosuppressive therapy. For such complex patients, a multidisciplinary approach and perseverance in the diagnostic evaluation of the etiology of myocarditis are necessary for adequate treatment.