Purulent Pericardial Abscess Caused by Escherichia coli in an Immunocompromised Patient Presenting With Mixed Septic and Cardiogenic Shock

Purulent pericarditis and pericardial abscess are rare yet life-threatening complications of bacterial infection, particularly among immunocompromised individuals. We report the case of a 76-year-old woman with multiple myeloma undergoing chemotherapy who presented with lumbar pain, fever, hypotension, and acute kidney injury. Imaging revealed a large pericardial abscess with a distinct air-fluid level. Despite broad-spectrum antibiotics, fluid resuscitation, and high-dose vasopressor therapy, she progressed to mixed septic and cardiogenic shock. Urgent pericardiectomy drained purulent material that later cultured <i>Escherichia coli</i>, consistent with blood and urine culture results. Her clinical course was complicated by mediastinitis but improved with targeted antimicrobial therapy. She was discharged after 38 days. This case highlights the diagnostic challenges and the critical role of early imaging and prompt surgical intervention in purulent pericarditis, especially in immunocompromised hosts.