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

Acute pericarditis, an inflammation of the pericardium with or without effusion, is rare in children but can progress to serious complications like cardiac tamponade. While many cases are idiopathic, presumed viral or post-viral, bacterial infections, particularly bacteremia, are also common identifiable causes. Management depends on the severity and underlying cause; viral cases often involve NSAIDs and colchicine, while bacterial pericarditis requires antibiotics and potentially pericardial drainage. This case report details a 14-month-old girl with acute pericarditis complicated by MRSA bloodstream infection following influenza B infection, successfully treated without pericardial drainage, to highlight the complexities of managing this condition in children.

The literature review section cites numerous studies on acute pericarditis in children, emphasizing the rarity of the condition and the varied etiologies. Several papers discuss the management of both viral and bacterial pericarditis, highlighting the importance of timely diagnosis and appropriate treatment strategies. Studies on influenza-associated myopericarditis and pericarditis are also referenced, alongside publications on the clinical presentation and management of MRSA pericarditis. The review underscores the significance of identifying the causative organism to guide effective treatment and improve outcomes, particularly concerning the potential for secondary bacterial infections following viral infections like influenza.

This is a case report, describing a single patient's clinical presentation, diagnostic workup, treatment, and outcome. The methodology involved detailed physical examination, laboratory tests (including complete blood count, inflammatory markers, blood cultures), electrocardiography, chest X-ray, transthoracic echocardiography, and computed tomography. The patient's response to treatment, including vancomycin, aspirin, and colchicine, was closely monitored using frequent bedside ultrasound examinations. Microbial analysis, including mass spectrometry, identified the causative organism. The duration of antibiotic treatment was determined based on the presence and severity of complications due to MRSA infection. A 4-year follow-up was conducted to assess for any complications or recurrences.

A 14-month-old girl presented with a nine-day history of fever and worsening dyspnea following a diagnosis of influenza B infection. Physical examination revealed phlebitis at a peripheral venous catheter insertion site. Electrocardiography showed ST segment elevations, and echocardiography confirmed pericardial effusion. Blood cultures grew MRSA, confirming a diagnosis of acute pericarditis complicated by MRSA bloodstream infection. Treatment with vancomycin, aspirin, and colchicine led to a significant improvement in the patient's condition, with resolution of the pericardial effusion. Frequent bedside echocardiography played a crucial role in monitoring treatment response. The patient was discharged after two weeks of intravenous antimicrobial therapy and continued outpatient treatment with aspirin and colchicine. No complications or recurrence were observed during a four-year follow-up. The minimum inhibitory concentration for the MRSA isolate was determined for various antibiotics.

This case highlights the potential for severe complications following influenza B infection, including secondary bacterial infections leading to acute pericarditis and sepsis. While influenza B is a less frequent cause of pericarditis than influenza A, this case demonstrates the possibility of severe disease. The rapid deterioration of the patient's condition emphasizes the importance of prompt diagnosis and targeted therapy. The case supports the existing literature on the management of bacterial pericarditis, particularly those caused by MRSA. The successful resolution of the pericardial effusion without pericardiocentesis underscores the potential for effective medical management in certain cases. The role of frequent bedside echocardiography in monitoring treatment response is also emphasized.

This case report demonstrates the potential for serious complications, such as acute pericarditis and MRSA bloodstream infection, following influenza B infection in children. Early diagnosis and prompt treatment with targeted antibiotics and anti-inflammatory agents are crucial for managing such cases. Careful clinical monitoring, including frequent bedside echocardiography, is essential to assess treatment response and prevent potentially life-threatening complications. Future research should focus on understanding the immunologic mechanisms underlying the increased susceptibility to secondary bacterial infections following influenza infection.

As a single case report, this study's findings cannot be generalized to the broader population. Further studies, including larger cohort studies, are needed to validate these observations and define the incidence and optimal management strategies for similar cases. The causal relationship between the influenza B virus infection and the subsequent MRSA pericarditis remains speculative, though the temporal relationship suggests a possible connection.