(577) Parvovirus B19 Myocarditis in a Covid19 MIS-C Syndrome: Cause or Causality?

INTRODUCTION: Myocarditis has been recognized as one of major complication during COVID 19 infections and vaccination. Few data are currently available on viral detection during myocardial damage in pediatric population. CASE REPORT: A previously healthy 13 year old boy presented with abdominal pain, vomiting and fever at the Emergency Department in Bambino Gesù Children's Hospital in Rome. A previous asymptomatic SARS-CoV2 infection had occurred two months before. Abdominal ultrasound showed minimal fluid distension in absence of significant peritoneal thickening. Nasopharyngeal swab was again positive for SARS CoV-2 at the time of admission. The clinical scenario evolved rapidly with frequent diarrhoea, hypotension and a gallop rhythm. Laboratory tests showed a progressive rise of inflammatory indices (C reactive protein, procalcitonin, ferritin and leucocytosis with lymphopenia) and cardiac enzymes - NTproBNP 9,000 ng/ml, troponin 1,500 ng/ml (normal < 14 ng/ml). The echocardiogram showed severe left ventricular dysfunction without dilation and with mild pericardial effusion. Due to rapid progression to cardiogenic shock, the patient was intubated and inotropic support commenced. Endomyocardial biopsy showed an inflammatory lympho-monocyte interstitial infiltrate (CD3++, CD4+, CD8++, TIA-1+, Granzyme B+, CD20+/- and MUM1-) with myocellular cytotoxic aggression and necrosis. Only Parvovirus B19 (PVB 19) was found in the biopsy. The patient was treated with high dose intravenous immunoglobulins (2 g/kg) and 24 hours after the infusion, the LVEF recovered from 25 to 50%. After 7 days the Sars-CoV-2 swabs were negative. The patient was discharged after 20 days with normal cardiac function. No major arrhythmias were detected during hospitalization. Cardiac MRI performed after 3 months showed no myocardial damage and normal biventricular function. Aldactone was administered for 6 months. After 18 months the patients is asymptomatic, cardiac echocardiogram, EKG and functional tests are normal. SUMMARY: Our case suggests that during a multisystem Inflammatory syndrome due to SARS-CoV2 infection, a latent, Parvovirus B19 infection was associated with an acute viral myocarditis leading to severe cardiac dysfunction and cardiogenic shock.