Case Presentation: A 44-year-old female with a past medical history of uncontrolled type 2 diabetes mellitus (hemoglobin A1c 16.5%), hypertension, and obesity presented to the emergency room (ER) for left sided facial swelling after a mosquito bite. Physical exam revealed swelling, erythema, and tenderness and she was diagnosed with facial cellulitis, for which she was discharged home with clindamycin. Three weeks later, she presented to the ER for new right-sided chest pain and was diagnosed with pneumonia and sent home with antibiotics. At her one-week follow-up she was febrile and complained of persistent chest pain. Electrocardiogram (ECG) revealed diffuse ST-elevations and her troponin I level was 0.06 ng/mL. She was admitted to the hospital and underwent urgent cardiac catheterization which revealed non-obstructive coronary arteries. A bedside transthoracic echocardiogram (TTE) showed a small pericardial effusion without tamponade. Blood cultures from admission grew methicillin-resistant Staphylococcus aureus (MRSA), so Vancomycin was started. Computed tomography of the chest showed bilateral pleural effusions and a right upper lobe consolidation. Blood cultures remained persistently positive for MRSA despite antibiotics. On day four of admission a repeat TTE showed worsening of the pericardial effusion. Pericardiocentesis with drain placement was performed and drained purulent fluid. Analysis of the fluid revealed 22,250 white blood cells/uL, 90% neutrophils, and was positive for MRSA. A transesophageal echocardiogram was then performed and showed no evidence of vegetations. Three days after drain placement a repeat TTE showed significant improvement of the pericardial effusion. Her symptoms improved and the pericardial drain was removed. Blood cultures showed clearance of her bacteremia and she was discharged with four weeks of Vancomycin followed by two weeks of daily Rifampin plus Levofloxacin every other day.

Discussion: We present a unique and rare case of acute purulent pericarditis due to MRSA. Initially, our patient underwent cardiac catheterization as acute pericarditis can present with ST-elevations and increases in troponin similar to acute myocardial infarctions. However, acute pericarditis can be differentiated from myocardial infarction by the number and pattern of ECG leads with ST-elevations. Despite treatment with Vancomycin, she remained persistently bacteremic and her pericardial effusion worsened. Pericardiocentesis revealed purulent pericarditis, which is rare and encompasses less than one percent of pericardial disease [1]. MRSA purulent pericarditis is even more uncommon and only a few cases have been described in the literature [2-17]. Her underlying uncontrolled diabetes and other comorbidities likely played a significant role in her development of this infection.

Conclusions: Purulent pericarditis is a life-threatening condition and early recognition is paramount to appropriate management and treatment. This case highlights several important points. First, we present an interesting and rare case of MRSA purulent pericarditis and the significance of adequate drainage to achieve source control. Second, we discuss how ECG findings for acute pericarditis may differ from acute myocardial infarctions. Lastly, we emphasize the significance of her uncontrolled diabetes as a risk factor for her development of this severe infection. Our patient successfully recovered after completion of her treatment.