eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiology

Pericarditis, Bacterial

Author: John Berger, MD, Departments of Critical Care Medicine and Pediatric Cardiology, Assistant Professor, George Washington University and Children's National Medical Center
Contributor Information and Disclosures

Updated: Jul 15, 2008

Introduction

Background

Purulent pericarditis is a rare but life-threatening bacterial infection. Purulent pericarditis refers to pericardial fluid that is either culture positive regardless of appearance or purulent appearing despite, in some instances, an inability to obtain a positive culture finding. This bacterial infection of the pericardium produces pericardial effusion that, if untreated, can lead rapidly to hemodynamic collapse, tamponade, and death. The signs of bacterial pericarditis are nonspecific; thus, a high index of suspicion is required to institute life-saving therapy. Proper treatment requires appropriate antibiotics and pericardial drainage.

Pathophysiology

The pericardium, which is composed of visceral and parietal layers, envelops the heart and great vessels. The pericardium provides a membrane barrier that protects the heart from infection, limits acute myocardial distention, decreases friction, and modulates ventricular interdependence. In healthy adults, the pericardial space contains approximately 20 mL of fluid, which has the appearance of a plasma ultrafiltrate.

Bacterial pericarditis most commonly occurs as a direct extension of an infection from an adjacent pneumonia or empyema. Alternatively, a distant infection can hematogenously seed the pericardium. Primary infection of the pericardium is rare. With inflammation, the pericardium becomes permeable to protein, and fluid accumulates between the visceral and parietal layers. Because the pericardium has a limited ability to stretch acutely, rapid accumulation of fluid leads to increased intrapericardial pressure and hemodynamic compromise.

Tamponade occurs when pericardial fluid accumulates rapidly enough or in sufficient volume to impair diastolic filling. During tamponade, all 4 cardiac chambers compete for space within the pericardium, producing increased systemic venous, pulmonary venous, and atrial pressures. Initially, an increased ejection fraction and tachycardia maintain cardiac output. When these mechanisms fail, systemic vascular resistance rises to maintain blood pressure, and the pulse pressure narrows. Any further increase in pericardial volume compromises ventricular filling, producing systemic hypotension and cardiovascular collapse. Volume and rapidity of fluid accumulation both determine whether a pericardial effusion produces tamponade.

With treatment, purulent pericarditis usually resolves without sequelae. Some patients may develop constrictive pericarditis.

Frequency

United States

Bacterial pericarditis is a rare disease. Its incidence appears to be decreasing, perhaps because of earlier treatment of primary infections and availability of Haemophilus influenzae immunization.

International

Compared with the United States, bacterial pericarditis may occur more frequently in developing nations. This increased incidence has been associated with delay in diagnosis and treatment of serious bacterial infections, malnutrition, and overcrowding.

Mortality/Morbidity

Without treatment, the mortality rate of bacterial pericarditis approaches 100%. Treatment with antibiotics and pericardial drainage decreases the mortality rate to 2-20% in modern case series. Treatment without early and adequate pericardial drainage significantly increases the risk of death. Other risk factors for increased mortality include tamponade or myocardial involvement, delays in diagnosis or delays in institution of therapy, infection with Staphylococcus aureus, and malnutrition.

Constrictive pericarditis is an infrequent sequel of purulent pericarditis. Signs can develop as early as 15 days after onset of the acute illness. Pericardiectomy usually resolves the symptoms.

Sex

Purulent pericarditis affects both sexes nearly equally.

Age

Most cases of purulent pericarditis occur in children younger than 4 years. Infants may not present with typical or classic features. For example, in one study, no patient younger than 18 months had a friction rub. In infants, almost all cases of pericarditis have a bacterial etiology.

Clinical

History

Patients are acutely ill and exhibit symptoms of sepsis. Acute purulent pericarditis in an infant is a medical emergency. Rapid evaluation, diagnosis, and treatment is essential.

• Symptoms are often nonspecific and include fever, respiratory distress, and tachycardia out of proportion to the degree of fever.
• Children may complain of abdominal discomfort.
• Most patients have preceding or concurrent infection that is the source of pericarditis. These infections include the following:
  • Pneumonia
  • Meningitis
  • Acute osteomyelitis
  • Acute arthritis
  • Soft tissue infections
• Pericarditis may rarely complicate neonatal sepsis.
• Precordial chest pain in not a frequent symptom, especially in young children.
  • The pain, if present, may be sharp or dull.
  • Supine position, chest wall motion, or coughing may worsen the pain.
  • Sitting forward may relieve the pain.

Physical

Infants with bacterial pericarditis are generally very ill and can present with signs of severe sepsis and shock. A high index of suspicion is required.

• Tachypnea and tachycardia out of proportion to fever is characteristic of both purulent pericarditis and acute myocarditis.
• Purulent pericarditis should be suspected in any infant who appears to have sepsis and has an abnormal cardiovascular examination.
• Cardiac findings may include the following:
  • Classic findings of pericarditis include muffled heart sounds and a friction rub.
  • A friction rub is a high-pitched scratchy sound that can occur in any combination of systole, mid diastole, and late diastole.
  • A friction rub is unlikely in the presence of a large pericardial effusion.
  • Rub may vary with patient position or the respiratory cycle and may be transient.
  • Infants with purulent pericarditis seldom demonstrate a rub.
  • Diastolic filling sounds may be heard.
• Signs of venous congestion may be present, including hepatomegaly and jugular venous distention. Jugular veins are difficult to assess in infants.
• Tamponade occurs when enough pericardial fluid accumulates to impair diastolic ventricular filling and, subsequently, cardiac output.
  • Tamponade can present rapidly with hypotension, soft heart tones of poor quality, and signs of venous congestion indicating acute cardiac decompensation.
  • Alternatively, tamponade can develop more insidiously, presenting a picture of right heart failure.
  • Signs of tamponade include dyspnea, tachycardia, narrow pulse pressure, pulsus paradoxus, and venous congestion.
• Pulsus paradoxus is a decrease in systolic blood pressure more than 10 mm Hg with inspiration. Any significant pericardial constriction produces this finding. Other causes of pulsus paradoxus include hypovolemia and either a large or small airway obstruction like with epiglottitis or asthma.

Causes

Most cases of purulent pericarditis are associated with a preexisting or concurrent infection such as pneumonia with or without empyema, meningitis, osteomyelitis, arthritis, or other soft tissue infections. Patients recovering from thoracic, cardiac, or esophageal surgery are at risk for purulent pericarditis. Purulent pericarditis has been reported in patients recovering from traumatic injury.

The organisms that most commonly cause purulent pericarditis include S aureus, H influenzae, Neisseria meningitidis, and Streptococcus pneumoniae. Less common organisms include gram-negative enteric bacilli, Pseudomonas aeruginosa, Salmonella species, Francisella tularensis, and anaerobic bacteria and fungi (Histoplasma species, coccidioidomycosis, blastomycosis, Aspergillus species, Candida species).

• S aureus
  • This is the most common organism in children, causing approximately 40% of cases.
  • Pericarditis occurs concomitantly in patients who have pneumonia with empyema and less often in patients with acute osteomyelitis or soft tissue abscess. Rarely, pericarditis is associated with S aureus endocarditis.
  • Necrotizing infection and exotoxin production lead to increased incidence of shock and higher mortality risk.
  • Within the first 3 months after cardiac surgery, S aureus is the most common cause of purulent pericarditis.
• H influenzae
  • This is the second most common organism listed in most reported pediatric case series of purulent pericarditis, although comprehensive data since the introduction of routine immunization is lacking.
  • Infection of the upper or lower respiratory tract frequently precedes pericarditis caused by H influenzae. Purulent pericarditis may occur with H influenzae meningitis.
  • H influenzae produces very thick fibrinopurulent exudate.
• N meningitidis
  • Pericarditis occurs in approximately 5% of young adults with meningococcemia.
  • The clinical course is often milder than with other causes of purulent pericarditis.
  • Pericardial effusion can be detected at the onset of the illness or later in the course of the infection. Late onset effusions have a purulent appearance but are usually sterile. Whether this late appearing effusion represents an infection, hypersensitivity to an antibiotic, or an immunologic response to the primary infection is unclear.
• S pneumoniae: At one time, S pneumoniae was the leading cause of purulent pericarditis, but it has become much less common perhaps because of widespread use of antibiotics.
• Other organisms
  • Other unusual organisms, such as gram-negative enteric bacilli and anaerobes or fungi, are rare but should be considered in patients who are immunocompromised.
  • Aspergillus pericarditis arises as a result of pulmonary infection in patients who are immunocompromised. Patients have a very poor prognosis. Therapy includes long-term amphotericin B or itraconazole. Successful therapy relies on recovery of adequate immune function.
  • Mycoplasma pneumoniae pericarditis is associated with pulmonary disease. The effusion responds to erythromycin.

• Search for CME/CE on This Topic »

• Pericarditis, Viral (Pediatrics: Cardiac Disease and Critical Care Medicine)
• Pericarditis, Constrictive (Cardiology)
• Pericarditis, Acute (Cardiology)
• Amebiasis (Pediatrics: General Medicine)

• Flu Cuts Risk of Bacterial Infection in Infants
• Bacterial Meningitis Risk Heightened in HIV Patients
• Oral and Vaginal Metronidazole Both Effective for Bacterial Vaginosis During Pregnancy

• Gastropericardial Fistula-induced Pericarditis: An Unusual Consequence of GERD
• British HIV Association Guidelines for HIV-associated Malignancies 2008
• 2009 H1N1 Influenza -- Just the Facts: Clinical Features and Epidemiology

• Prostatitis Resource Center
• Cornea and External Disease Resource Center
• Pneumonia Resource Center