Case Report: Acute Methicillin-Sensitive Staphylococcus aureus Pericarditis in a Diabetic Patient

Daniel James Lim¹Richard Lu¹Edwin Chong Yu Sng²Felix Maverick Rubillar Uy¹Wei Liang Huang¹Siang Chew CHAI¹Anthony Chau Ang Yii³Ing Xiang Soo⁴Jenn Nee Khoo⁵Xu Cong Ruan^1*

• ¹Changi General Hospital Department of Cardiology, Singapore, Singapore
• ²Changi General Hospital Department of Infectious Diseases, Singapore, Singapore
• ³National Heart Centre Singapore Department of Cardiothoracic Surgery, Singapore, Singapore
• ⁴Department of Cardiothoracic Surgery, National Heart Centre Singapore, Singapore, Singapore
• ⁵Changi General Hospital Department of Radiology, Singapore, Singapore

Introduction Bacterial pericarditis is rare in the antibiotic era but remains potentially fatal due to rapid progression and high mortality. We report an unusual case of methicillin-sensitive Staphylococcus aureus (MSSA) pericarditis with a transudative pleural effusion in a patient with poorly controlled type 2 diabetes mellitus (DM), illustrating the diagnostic and therapeutic challenges in a complex patient. Patient concerns and clinical findings A 47-year-old with a history of presumptive ischemic cardiomyopathy, uncontrolled DM (HbA1c 14.2%) and treated pulmonary TB presented with pleuritic chest tightness, fever and dyspnea. Examination and investigations revealed a moderate-to-large pericardial effusion, ST-segment elevation on electrocardiogram (ECG) and raised inflammatory markers. Imaging raised suspicion for bacterial pericarditis, though pleural fluid analysis was transudative. Diagnosis, interventions and outcomes Pericardiocentesis was not feasible due to effusion loculation and absence of a safe window, but Staphylococcus aureus was detected by polymerase chain reaction testing of pleural fluid. Cardiothoracic surgeons performed a pericardial window and biopsy confirming MSSA pericarditis. Surgical drainage was successful and the patient completed six weeks of intravenous cefazolin with full recovery. Conclusion This case emphasizes the need to consider bacterial etiologies, including MSSA, in evaluating pericarditis among immunocompromised patients, especially those with DM or prior TB. Multimodality imaging, molecular diagnostics and early surgical consultation are important in cases where pericardiocentesis is not feasible. Invasive diagnostic strategies may be critical for achieving microbiological diagnosis and ensuring timely source control. Multidisciplinary collaboration is essential in managing complex pericardial infections to optimize diagnostic certainty and outcomes.