Complicated Acute Pericarditis and Peripheral Venous Catheter-Related Bloodstream Infection Caused by Methicillin-Resistant Staphylococcus aureus after Influenza B Virus Infection: A Case Report

Background: We report a 14-month-old girl with a 9-day history of fever and worsening dyspnea who had tested positive for influenza B virus 7 days prior without receiving treatment. At presentation, there was redness and swelling at a prior peripheral venous catheter (PVC) insertion site. Electrocardiography showed ST-segment elevations in leads II, III, aVF, and V2–V6; emergent transthoracic echocardiography revealed pericardial effusion without ventricular dysfunction, so pericardiocentesis was not performed. Blood cultures grew methicillin-resistant Staphylococcus aureus (MRSA). A diagnosis of acute pericarditis complicated by sepsis and PVC-related bloodstream infection (PVC-BSI) due to MRSA was made. Frequent bedside ultrasound examinations were used to monitor treatment. After administering vancomycin, aspirin, and colchicine, the patient stabilized. Conclusions: In children with acute pericarditis, rapid identification of the causative organism and targeted therapy are crucial to prevent deterioration and mortality, with close monitoring for progression to cardiac tamponade and to evaluate treatment response.