A Rare Case of MRSA Pericarditis with Expanding, Purulent Pericardial Effusion Leading to Uremic Kidney Failure from a Right, Necrotic Toe

Purulent pericarditis is an extremely rare entity with only a few reported cases so far. This condition deserves prompt diagnosis because of its significant mortality rate if left untreated. A 76-year-old man with a past medical history of coronary artery disease (CAD) with percutaneous coronary intervention (PCI) to the left anterior descending artery (LAD) and right circumflex artery (RCA), ischemic cardiomyopathy with moderately reduced ejection fraction (EF 45-50%), peripheral artery disease (PAD), COVID-19 pneumonia complicated by fibrotic lung disease (on 3 liters of home oxygen), type-2 diabetes mellitus (T2DM), hypertension (HTN), hyperlipidemia (HLD), and chronic kidney disease (CKD) stage III presented with complaints of pleuritic chest pain and shortness of breath. On hospital day 1, he was afebrile and hemodynamically stable with physical exam remarkable for bibasilar crackles and dry gangrene of his right first toe. He developed progressive altered mental status, hypotension, oliguric renal failure, and respiratory distress on hospital day 6. On exam at this time, he had an elevated jugular venous distension (JVD) of 12-14 cm water, pericardial friction rub with decreased heart sounds, and orthopnea; all were consistent with cardiac tamponade clinically. An electrocardiogram (EKG) showed new ST elevations in leads I, II, and aVL with ST depression in aVR and V1 with only mild elevation in troponin I to 0.07 ng/mL. A transthoracic echocardiogram (TTE) was done on hospital day 7 and showed a moderate sized pericardial effusion with inferior vena cava (IVC) enlargement but no atrial collapse, ventricular collapse, IVC collapse, or respiratory variation in the mitral and tricuspid inflow velocities. Blood cultures grew methicillin-resistant Staphylococcus aureus (MRSA) on hospital day 6, and he was started on intravenous (IV) vancomycin. The differential diagnosis for his enlarging pericardial effusion included purulent pericarditis, uremic pericarditis, or hemorrhagic effusion. He had urgent diagnostic and therapeutic pericardiocentesis with removal of 350 milliliters of fluid. The pericardial fluid was cloudy, tan-brown with a gram stain showing gram-positive cocci in clusters and cultures growing MRSA, which confirmed the diagnosis of purulent pericarditis secondary to MRSA infection. After the pericardiocentesis, his blood pressure, respiratory distress, and renal failure improved. The source of the bacteremia was from osteomyelitis of his gangrenous, right toe with bone biopsy growing both MRSA and Streptococcus anginosus. He underwent toe amputation for definitive source control. He was discharged on hospital day 24 with a plan to complete 6 weeks of IV vancomycin.