Discussion
Purulent pericarditis is an infection localized within the pericardial space. Most cases are secondary to an infectious process elsewhere, which could be of bacterial, viral, fungal, or parasitic etiology.1 Five mechanisms could lead the infecting organism to infect the pericardial space; contiguous spread from intrathoracic site, hematogenous spread, extension from myocardial site, perforating injury or surgery, and extension from a subdiaphragmatic site.1 Predisposing factors for the development of this condition include malignancy, chronic kidney disease, immunosuppression, diabetes mellitus, and alcohol misuse. Pericarditis is an infection localized within the pericardial space.
Purulent pericarditis has become a rare entity in the antibiotic era.2 Prior to the development of antibiotics, most cases were secondary to S pneumoniae.1,2,5,6 As per Cilloniz and colleagues, about 40% to 50% of all cases of purulent pericarditis are caused by Gram-positive bacteria, mostly S pneumoniae.5 In this case study, bacterial culture did not reveal growth of an organism—most likely because the patient had received antibiotics elsewhere. However, Gram-positive cocci were seen within the initial pericardial aspirate. This organism was suspected to have spread contiguously from a pulmonary focus, which also led to pleural effusions.
Since the patient in this case study had no history of thoracic surgery, malignancy, or other immunosuppression, the patient’s history of alcohol misuse was the only predisposing factor for development of purulent pericarditis. Contrary to the common presentation of pericarditis, purulent pericarditis may not have the common clinical findings, such as chest pain, pericardial friction rub, and distended neck veins.2,3 Furthermore, according to Parikh and colleagues, about 35% of affected patients may have a normal electrocardiogram.2 Hence, the diagnosis of purulent pericarditis often is missed because the classic signs of pericarditis are often absent, and other nonspecific symptoms are attributed to initial underlying infection.7
A high index of suspicion is needed to diagnose purulent pericarditis. Once a diagnosis is made, initial treatment should consist of prompt drainage of pericardial fluid combined with systemic antibiotic therapy. Vancomycin and a third-generation cephalosporin may be started empirically until results of pericardial fluid cultures become available.3 Drainage can be achieved by pericardiocentesis, pericardiotomy, or pericardiectomy (partial or total).1 In cases of hemodynamic instability due to cardiac tamponade, sonographically guided pericardiocentesis should be undertaken and an indwelling pericardial catheter left in place.1 Although this is the simplest and fastest method of evacuation, it may not be effective when dealing with thick, fibrinous fluid. In such cases, intrapericardial fibrinolysis may be considered. This approach may be undertaken early in the process, after drainage insertion, or as salvage therapy, when there has been incomplete evacuation of purulent material or open surgical drainage is not available.
Streptokinase, urokinase, and tissue plasminogen activator have been used for intrapericadial fibrinolysis.1 However, there is no definite data on dosage or frequency at which these medications should be administered. No matter the therapeutic approach, effective drainage of the pericardial fluid is crucial to avoid the development of pericardial constriction. Constrictive pericarditis occurs when fibrosis and adhesions create a dense pericardium that encases the heart. This causes impaired ventricular filling that can lead eventually to heart failure.4 Pericardiectomy is the definitive treatment for constrictive pericarditis.
Conclusion
Although purulent pericarditis has become a rare diagnosis since the development of antibiotics, knowledge of how to identify it is essential since mortality reaches 100% if the diagnosis is missed.4 Even when the condition is promptly diagnosed and treated, mortality is 40%, mainly due to cardiac tamponade, septic shock, or constriction.1 The case presented here illustrates the clinical features associated with this condition. Knowing these features can translate in a successful patient outcome.