A case report of eosinophilic granulomatosis and polyangiitis myocarditis presenting as ST elevation myocardial infarction and showing positive response to immunotherapy

BACKGROUND: Acute ST elevation myocardial infarction (STEMI) is a medical emergency and is most commonly due to atherosclerotic plaque rupture and occlusion of coronary vessels. This case demonstrates that eosinophilic granulomatosis with polyangiitis (EGPA) myocarditis can mimic acute STEMI. CASE SUMMARY: A 44-year-old woman presented with acute chest pain, shortness of breath, and collapse with ST elevation on electrocardiography. Coronary angiogram showed unobstructed coronaries and chest film revealed left-sided consolidation. Together with a thorough history, serum eosinophilia, cardiac magnetic resonance (CMR), and computated tomography imaging, the patient was diagnosed with acute EGPA myocarditis. She responded tremendously to steroid and cyclophosphamide immunosuppression and subsequent CMR imaging demonstrated complete resolution of myocarditis. DISCUSSION: CMR played a crucial role in the diagnosis and follow-up of this rare presentation. In patients who present as a STEMI but show unobstructed coronary vessels, EGPA may be a possible diagnosis.