INTRODUCTION: We present the first case to our knowledge of pyopneumopericardium presenting after coronary stent placement secondary to an unlikely pathogen, Lancefield Group F Streptococci.
CASE PRESENTATION: A 48 year-old male with a past history of type two diabetes, hypertension, and dyslipidemia presented to the Emergency Department with 24 hours of chest discomfort. Electrocardiogram demonstrated ST-segment elevations of 1.5mm in the inferior leads. A bare metal stent was placed under angiography in the mid 70-80% occluded right coronary artery. Two days later, echocardiography revealed a pericardial effusion and 360mL of straw-colored fluid was drained under fluoroscopy. The patient was discharged after 3 days of no pericardial fluid culture growth and resolution of the effusion on echocardiogram. Three days later, he returned with orthopnea and pleuritic chest pain. The patient was afebrile with a pulse of 115, BP 96/66 mmHg, and oxygen saturation was 100%. Examination revealed a IV/VI crunch-like sound throughout the precordium, JVD at 5cm above the sternal angle, and decreased breath sounds at the left lung base. Laboratory results were significant for a WBC of 29,000 with 34% band forms and a creatinine of 3.5mg/dL. Review of the final pericardial fluid culture showed 1+ Group F Streptoccci on day five. Echocardiogram noted a large echodense layer within the pericardial space, preserved left ventricular function, and no collapse of the right ventricle. CT scan of the chest demonstrated low-density fluid and air in the pericardial space associated with significant pyopneumopericardium. He was started on high dose ampicillin IV for pathogen specific coverage, as well as empiric vancomycin and ciprofloxacin. The patient was urgently taken to the operating room where foul-smelling grayish-brown pus was found under pressure, emptied, and irregated from the pericardial space. A 36-french chest tube was placed. Repeat pericardial fluid culture grew 4+ Group F Streptococci. After a two-week hospitalization, the patient left the hospital ambulatory, with no neurologic deficits.
DISCUSSIONS: Pyopneumopericardium is rare. It usually results from trauma, foreign body, ingestion of caustic substances or invasive procedures(1). Mortality is often cited near 100 percent(2). In 1937, Louis Hamman noted a distinctive crunching noise (Hamman's Crunch) associated with pneumomediastinum, and the finding was present in this case. Patients often present with cardiac tamponade physiology. Twenty-five percent of cases are secondary to fistulae formation between the pericardial and pleural space, bronchial tree (bronchial carcinoma, invasive aspergillosis) or upper gastrointestinal tract (malignancy of stomach, esophagus, and amebic hepatic abscess)(4). Case-reports note spontaneous etiologies from gas-producing organisms(5). Although S. milleri has been reported as a rare cause of endocarditis and pericarditis secondary to alimentary tract fistula formation, this is the first case to our knowledge of pyopneumopericardium resulting from Lancefield Group F Streptococci. Of the group Streptococcus anginosus (“Streptococcus milleri”) have been implicated as etiologic agents in a variety of purulent infections, but because of heterogeneous characteristics, these organisms can be unrecognized or misidentified(6). They are normal flora of the gastrointestinal tract and perineum, and isolates are often dismissed in the laboratory as contaminating normal flora or harmless bystanders(7). Lancefield grouping with a full range of antisera and biochemical tests should be performed on all streptococci isolated from normally sterile sites such as the pericardium, or if present where no other pathogen can be isolated(8).
CONCLUSION: Pyopneumopericardium requires prompt imaging, antibiotic administration and surgical drainage. If completed, survival is possible. While normal flora, Group F streptococci should be aggressively treated as pathogenic if found in areas outside its normal habitat.
DISCLOSURE: Andrew Goldberg, No Financial Disclosure Information; No Product/Research Disclosure Information