(209) Pediatric Acute Papillary Muscle Rupture Causing Cardiogenic Shock and Hypoxemia Requiring VA ECMO

Introduction: Papillary muscles are crucial for proper mitral valve (MV) function. Papillary muscle rupture (PMR) is a rare but severe complication often arising from myocardial infarction, trauma, and myocarditis. It can lead to acute severe mitral valve regurgitation, pulmonary edema, and cardiogenic shock. PMR in pediatric cases of pancarditis with an underlying inflammatory process has not yet been documented.

Description: A 13-year-old boy with trisomy 21 presented with fever, syncope, and diarrhea, and was initially suspected of having septic shock. He required inotropes and BiPAP ventilation. The initial echocardiogram was unremarkable despite very high troponin levels. However, his condition rapidly worsened with hypoxemia, leading to cardiac arrests. Due to refractory hypoxemia and severe cardiogenic shock, the patient was started on VA ECMO. A repeat echocardiogram showed a large pericardial effusion, managed with pericardiocentesis. A coronary angiogram revealed normal coronary arteries. The subsequent day, an echocardiogram showed acute PMR, necessitating MV replacement with a mechanical valve. Pathology report revealed chronic inflammation of the myocardium and endocardium. All cultures were negative. Despite the evidence of Group A Strep infection, acute rheumatic fever was ruled out based on pathology results. The patient was treated with antibiotics and steroids, and successfully decannulated from ECMO. He remains at the CICU for ongoing care and further etiological investigation.

Discussion: This case highlights the critical need for early recognition of pancarditis and its rare complication, acute mitral regurgitation from PMR, even when initial cardiac function appears normal. It also underscores the importance of a broad differential diagnosis for pediatric pancarditis, considering both infectious and non-infectious causes.