BACKGROUND: Pericarditis is the inflammation of the pericardial sac due to a variety of stimuli that ultimately trigger a stereotyped immune response. This condition accounts for up to 5% of emergency department visits for nonischemic chest pain in Western Europe and North America. The most common symptoms of clinical presentation are chest pain and shortness of breath with associated unique electrocardiographic changes. Acute pericarditis is generally self-limited. However, some cases may be complicated by either tamponade or a large pericardial effusion, which carries a significant risk of recurrence. Risk factors for acute pericarditis include viral infections, cardiac surgery, and autoimmune disorders. A rarer cause of pericardial inflammation includes pneumonia, which can induce purulent pericarditis that has been increasingly rare since the advent of antibiotics. Purulent pericarditis carries a high fatality rate, especially in the setting of tamponade, and is invariably deadly without the administration of antibiotics. Bedside transthoracic echocardiogram is a quick and helpful method that can aid in the diagnosis and management. CASE SUMMARY: We present the case of a 62-year-old woman who sought medical attention at the emergency department (ED) due to a 5-day history of chest pain, shortness of breath, and subjective fevers. Laboratory findings in the ED were significant for leukocytosis and elevated erythrocyte sedimentation rate and C-reactive protein. A chest X-ray revealed a new focal density within the left lower lung base, and a bedside point-of-care ultrasound showed a pericardial fluid collection. The patient was subsequently admitted, where she underwent pericardiocentesis. Fluid cultures from drainage grew . She was started on broad-spectrum antibiotics immediately after the procedure. The patient was ultimately discharged in stable condition with cardiology and infectious disease follow-up. CONCLUSION: This case report emphasizes a unique complication of community-acquired pneumonia. Purulent pericarditis due to occurs intrathoracic spread of the organism to the pericardium. This condition is virtually fatal without the administration of antibiotics. Therefore, in the context of suspected pneumonia and a new pericardial fluid collection on imaging, clinicians should suspect purulent pericarditis until proven otherwise, which requires emergent intervention.