1043 INTEGRATED DIAGNOSIS AND TREATMENT IN EOSINOPHILIC MYOCARDITIS, THE IMPORTANCE OF TEAM AGAINST RARE CONDITIONS
Authors: Minnocci Melania , Trapanese Paola , Menozzi Matteo , Rampini Francesca , Bagnoli Alberto , Demola Pierluigi , Guiducci Vincenzo , Manca Francesco , Navazio Alessandro , Boriani Giuseppe 
Published: December 2022

Abstract
Eosinophilic myocarditis is an inflammatory disease of the heart, even if rare, it could be a life-threatening condition, characterized by eosinophils infiltration of the myocardial tissue. First report of this type of endocarditis was reported by Löffler in 1935 and was described as an eosinophilic filling of endocardial cells with consequent myocardial fibrosis.
Etiologically, viral infections are the prominent cause of myocarditis, especially the Coxsackie-B virus, drugs such as sumatriptan and canine Toxoplasma infections have been associated with eosinophilic myocarditis. Eosinophilia indeed (increase in eosinophils count in blood sample) has a similar etiology to eosinophilic myocarditis.
However, as known from the literature, the relationship between myocardial damage and eosinophilia can have multiple etiologies, from hypersensitivity to autoimmune diseases but also malignancies. Clinically, its signs and symptoms present a wide spectrum of manifestations such as chest pain, dyspnea, rhythm disturbances, until sudden cardiac death.
Diagnostic gold standard is endomyocardial biopsy, but cardiac magnetic resonance is a valid option in such scenarios following Lewis Lake criteria and suggestive laboratory results.
We present the case of a 78-year-old lady, affected by arterial hypertension and dyslipidemia. Among her main comorbidities she complained late-onset asthma and hypothyroidism. The patient went to the emergency department of our hospital for onset of dyspnea associated with chest pain. An echocardiogram showed a dilated and diffusely hypokinetic left ventricle, severely reduced systolic function (EF 30%) and atrial fibrillation with high ventricular response. The patient presented with acute pulmonary edema and oliguria, for which non-invasive ventilation, diuretics therapy and inotropic therapy were needed. Invasive coronary angiography was negative, excluding any kind of coronary syndrome. HS-troponin peak detected was very high (73.170 ng/L).
CMR was performed that showed images indicative of myocarditis (as shown in the picture A and B) with typical distribution of late gadolinium enhancement and reduced left ventricular function:
The finding of hypereosinophilia was highly suspicious, so the endomyocardial biopsy performed confirmed the histotype of eosinophilic myocarditis. Hypereosinophilic myeloproliferative syndrome was ruled out after genetic testing. Therefore, a final diagnosis of eosinophilic granulomatosis with ANCA-negative polyangiotis with predominantly hematologic (peripheral hypereosinophilia), cardiac (multifocal myocarditis with inflammatory infiltrate with predominantly eosinophilic component), pulmonary (late-onset asthma) and peripheral neurologic (sciatic mononeuropathy) involvement was made. The patient underwent corticosteroid therapy, to which mepolizumab and cyclophosphamide were added.
This case enlightens the rarity of this pathology, enhancing the appropriate indication of CMR in complex settings. We also remark the importance of close team collaboration with rheumatologists and CMR-expert radiologists for the resolution of the case and its proper therapeutic management.