Cardiac Tamponade Due to Purulent Pericarditis in an Immunocompetent Patient.

We report the case of a previously healthy 24-year-old man admitted with a right-sided empyema and community-acquired pneumonia who subsequently developed acute chest pain, worsening dyspnea, and hemodynamic instability. Point-of-care cardiac ultrasound (POCUS) revealed a large circumferential pericardial effusion with a "swinging heart" and diastolic collapse of the right chambers, consistent with cardiac tamponade. Urgent ultrasound-guided pericardiocentesis drained thick purulent fluid, and Streptococcus pneumoniae was identified by polymerase chain reaction (PCR). Targeted intravenous ceftriaxone was initiated. Following drainage, the patient showed clear clinical improvement, including stabilization of blood pressure, improved oxygen saturation, reduction of tachycardia, and resolution of chest pain. Residual loculated collections required pleural drainage and a video-assisted thoracoscopic pericardial window. This case underscores the crucial role of POCUS in the early detection of cardiac tamponade in patients with empyema-associated infections and highlights the importance of rapid intervention in preventing deterioration in purulent pericarditis.