P3C268: Preceding Respiratory Infection and Persistent Tachycardia: A Case of Purulent Pericarditis in an Otherwise Healthy Child

Introduction: Sinus tachycardia is perhaps the most common vital sign abnormality in the acutely ill patient, usually secondary to fever or dehydration. When tachycardia persists despite fluid and antipyretic therapy, it may portend a primary cardiac diagnosis and prompt evaluation is essential.

Case Description: A 14-month-old child was seen at a local emergency department for poor energy and appetite and increased work of breathing. She had tested positive for influenza A four days prior. The patient was empirically treated for superimposed bacterial pneumonia and received 40 mL/kg IV fluids but was transferred to our center for worsening respiratory distress. On arrival, the patient was tachycardic (>180bpm) and tachypneic on 10L of high flow nasal cannula. She was febrile to 39.4 degrees and responded to antipyretics but remained tachycardic. Chest X-ray showed no focal lung infiltrate but borderline cardiomegaly. ECG showed sinus tachycardia with PR depression and ST elevation (Figure 1). We obtained a cardiac point of care ultrasound (POCUS) and identified a large pericardial effusion with strands (Figure 2). Labs showed elevated B-type natriuretic peptide (783 pg/mL) and negative troponin. The patient was admitted to the ICU for presumed viral pericarditis but within a few hours developed worsening tachycardia and dyspnea, weak pulses, and poor perfusion. Echocardiogram showed indices of evolving tamponade. She was urgently taken for pericardiocentesis where 77mL of purulent fluid was removed and grew methicillin-susceptible staphylococcus aureus in culture. Despite appropriate IV antibiotic therapy, her hospital course was complicated by persistence of inflammation and pericardial effusion requiring drain to remain in place until hospital day 21. She also developed empyema necessitating chest tube placement for days 21-26. Evaluation for immunodeficiency and malignancy was negative. She was discharged on day 29 and completed a total of 66 days of antibiotics. On follow-up visits, she has had reassuring echocardiograms and no infection recurrence.

Discussion: Purulent pericarditis is exceedingly rare in immunocompetent children and is associated with preceding respiratory infection, likely due to intrathoracic bacterial translocation. Reports of pediatric purulent pericarditis in recent decades show staphylococcus aureus is the most common pathogen. This child’s toxic appearance and unremitting tachycardia suggested a cardiac process and triggered initial testing, including chest x-ray, ECG, labs, and POCUS, that indicated pericarditis. Pericardiocentesis was diagnostic and allowed early initiation of IV antibiotics. Purulent pericarditis is a high-risk diagnosis and, in this case, complicated by empyema and prolonged hospital stay. Long-term cardiology follow-up is advised due to continued risk for constrictive pericarditis.

Conclusion: Purulent pericarditis is a recognized complication of respiratory infections and should be considered when initial evaluation is suspicious for cardiac etiology. The availability of POCUS and early transfer to a center where interventional cardiology is available may facilitate prompt diagnosis and treatment.