Possible Cytomegalovirus-associated Massive Hemorrhagic Pericardial Effusion with Cardiac Tamponade in an Immunocompetent Elderly Woman

Cytomegalovirus (CMV) infection in immunocompetent individuals is typically mild or asymptomatic, but severe organ involvement may occur in older adults due to age-related immune dysregulation. CMV-associated pericardial disease is rare and often difficult to confirm microbiologically. An 80-year-old immunocompetent woman presented with dyspnea, cough, and fatigue and was found to have massive hemorrhagic pericardial effusion with impending cardiac tamponade. Clinical examination demonstrated tachycardia, pulsus paradoxus, elevated jugular venous pressure, and a pericardial rub without hypotension or hypoxia. Electrocardiography showed low-voltage QRS complexes without ischemic or classic pericarditis changes. Extensive evaluation excluded tuberculosis (TB), malignancy, autoimmune disease, and alternative viral etiologies. CMV Immunoglobulin M (IgM) and Immunoglobulin G (IgG) were positive with high IgG avidity of 91%. Pericardial fluid CMV polymerase chain reaction (PCR) was negative. Flow cytometry showed a lower-range CD4 count for age. Pericardial biopsy demonstrated inflammatory infiltrates only. Urgent drainage and antiviral therapy resulted in sustained recovery. CMV-associated inflammatory pericardial effusion should be considered in elderly patients after exclusion of common causes. Negative PCR does not exclude CMV involvement in late or immune-mediated presentations.