FIG 57.6 Transthoracic echocardiography in apical four-chamber view during pericardiocentesis The appearance of microbubbles (asterisk) in the pericardial space after an injection of agitated saline contrast confirms intrapericardial position of the pericardiocentesis needle LA, Left atrial; LV, left ventricle; RA, right atrial; RV, right ventricle A careful analysis of pericardial fluid is rewarding in most cases Drainage of pus confirms the diagnosis of bacterial pericarditis, while serosanguinous fluid has limited diagnostic utility Chylous effusion, rich in triglycerides, occurs after traumatic or surgical injury to the thoracic duct Typical gold-paint cholesterolrich effusion is seen in severe hypothyroidism In addition to routine measurement of hematocrit, cell counts, sugar, and protein, the pericardial fluid is subjected to special tests based on possible etiology In cases with a high suspicion of tuberculosis, pericardial fluid analysis should include measurement of adenosine deaminase and polymerase chain reaction–based detection of mycobacterium.3 In the appropriate clinical setting, pericardial fluid should also be subjected to measurement of tumor markers and malignant cells Based on local expertise, fluoroscopy or pericardioscopy guided pericardial biopsy may be performed if the diagnosis is crucial for management.3,4,68 Specific Pericardial Diseases Viral Pericarditis Viral infection is the most common cause of pericarditis in children Coxsackie virus is the commonest causative agent.4 The clinical symptoms and course are similar to other viral illnesses Patients with viral pericarditis are less toxic than those with bacterial pericarditis, unless there is associated myocarditis Pericardial effusion is common but tamponade is rare The pericardial fluid is serous or serosanguinous with lymphocytic predominance PCR studies are useful in determining a specific viral cause Bacterial Pericarditis Bacterial pericarditis is a serious, life-threatening disease occurring in children younger than 2 years.69 The lung is the most common source of infection Septic arthritis, osteomyelitis, meningitis, or other soft tissue infection may also cause hematogenous spread to the pericardium.70–72 Broad-spectrum antibiotics are mandatory and should be directed toward the most common causative organisms, that is, Staphylococcus aureus and Haemophilus influenzae.72,73 In general, initial treatment should include an intravenous penicillinase-resistant penicillin or vancomycin and a third-generation cephalosporin An aminoglycoside may be added in sick and immunocompromised children Antibiotics may be changed based on the culture and sensitivity pattern All children with bacterial pericarditis should be treated with intravenous antibiotics for at least 3 to 4 weeks, irrespective of the initial response in clinical status The penetration of antibiotics to the pericardial space is limited and therefore antibiotics alone may not be sufficient An early pericardiocentesis and continuous drainage reduces pericardial inflammation and promptly resolves acute illness In most centers worldwide, surgical drainage by creating a pericardial window is the standard treatment for purulent pericarditis An alternative strategy of intrapericardial fibrinolysis for thick effusion with strands and loculations is effective in complete drainage of pericardial collection Pericardial fibrinolysis is also shown to reduce pericardial constriction.74–77 There is no consensus on dosing, duration, and type of fibrinolytic agent In our unit, depending on echocardiographic appearance and consistency of pericardial collection, streptokinase is instilled at an initial dose of 5000 U/kg The dose and frequency of instillation is adjusted according to the liquefaction of pericardial collection, with most children requiring once daily dose of 5000 U/Kg A single dose should not exceed a total of 100,000 U The pericardial collection is aspirated frequently Careful clinical and echocardiographic monitoring is necessary to avoid rare yet potentially serious complications such as cardiac rupture and pericardial hemorrhage Hemoglobin content of the fluid is measured if the aspirate is hemorrhagic Complication related to systemic fibrinolysis is generally not seen with intrapericardial fibrinolysis.76 A duration of 8 to 10 days is generally sufficient Pigtail catheter is removed once daily pericardial aspirate is less than 5 to 10 mL and there is no reaccumulation on echocardiography If the fluid cannot be aspirated percutaneously, a surgical creation of pericardial window or pericardiectomy is considered Those developing pericardial constriction warrant pericardiectomy In the current era, the survival of patients having bacterial pericarditis is greater than 90%.72,73,77 Younger age at diagnosis, septicemia, tamponade, delay in diagnosis and treatment, concurrent myocarditis, and staphylococcal pericarditis portend poorer prognosis.71,72 The exact incidence of pericardial constriction following bacterial pericarditis is not known but is common with Staphylococcus aureus, Haemophilus influenzae, and Streptococcus pneumoniae pericarditis.70,72,78 Tubercular Pericarditis Tubercular pericarditis accounts for approximately 4% of pericardial diseases in developed countries, but continues to remain a common problem in developing countries.79 It typically presents with insidious onset of low-grade fever, night sweats, weight loss, malaise, dyspnea, and nonspecific chest pain It is often due to direct extension of pulmonary tuberculosis but can also result from hematogenous spread from other foci In the appropriate clinical setting, lymphocytic predominance, positive stain for acid-fast bacilli, and elevated adenosine deaminase levels greater than 50 U/L in pericardial fluid are diagnostic of tubercular pericarditis and is sufficient to initiate antitubercular therapy.79,80 Antitubercular therapy includes 2 months of an intensive phase consisting of four drugs—rifampicin, isoniazid, pyrazinamide, and ethambutol— followed by 4 months of maintenance phase with isoniazid and rifampicin In