Purulent pericarditis

Pericardial effusion with tamponade

Purulent Pericarditis is a rare but severe form of pericarditis, which is an inflammation of the pericardium, the fibrous sac surrounding the heart. Unlike other forms of pericarditis, purulent pericarditis involves the accumulation of pus within the pericardial space, leading to a significant risk of complications such as cardiac tamponade, a life-threatening condition where the accumulation of fluid, in this case, pus, compresses the heart and impairs its ability to function properly.

Causes

Purulent pericarditis is most commonly caused by a bacterial infection. The most frequent pathogens include Staphylococcus aureus, Streptococcus pneumoniae, and other gram-positive bacteria. However, it can also be caused by gram-negative bacteria and, in rare cases, by fungal infections. The infection can reach the pericardial space through different pathways: direct spread from adjacent infections (like pneumonia or mediastinitis), hematogenous spread (through the bloodstream), spread from an infected intravenous catheter, or following cardiac surgery or trauma.

Symptoms

The symptoms of purulent pericarditis can be severe and include fever, chest pain that may improve when sitting up and leaning forward, dyspnea (difficulty breathing), and general signs of infection such as malaise and tachycardia (rapid heartbeat). Due to the nature of the infection, symptoms can rapidly progress, leading to signs of cardiac tamponade, including hypotension (low blood pressure), jugular venous distension, and muffled heart sounds.

Diagnosis

Diagnosis of purulent pericarditis involves a combination of clinical assessment, laboratory tests, imaging studies, and pericardial fluid analysis. Echocardiography is a key imaging tool that can reveal the presence of pericardial effusion (fluid accumulation) and its hemodynamic impact. Pericardiocentesis, the procedure of aspirating fluid from the pericardial space, not only aids in diagnosis by obtaining pus for microbiological analysis but can also be therapeutic.

Treatment

The treatment of purulent pericarditis is aggressive and requires both the management of the infection and the relief of cardiac tamponade if present. Antibiotic therapy is initiated based on the suspected or confirmed pathogens and later adjusted according to culture results. Broad-spectrum antibiotics are often used initially, given the potential severity of the infection. In cases where cardiac tamponade is threatening the patient's life, pericardiocentesis or even surgical drainage through a pericardiotomy may be necessary to relieve the pressure on the heart. In some instances, a pericardial window, a procedure to create a drainage pathway from the pericardial space to the abdominal cavity, is performed to prevent fluid reaccumulation.

Prognosis

The prognosis of purulent pericarditis has improved with advances in medical and surgical treatments but remains serious. The outcome largely depends on the speed of diagnosis and initiation of treatment, the causative organism, and the presence of underlying heart disease or other comorbidities. Complications can include constrictive pericarditis, a chronic condition where the pericardium becomes thickened and scarred, leading to impaired heart function.

Prevention

Prevention of purulent pericarditis involves prompt treatment of bacterial infections, careful monitoring of patients with risk factors such as those with intravenous catheters or those who have undergone cardiac surgery, and measures to prevent hospital-acquired infections.