Tuberculous pericarditis

Tuberculous pericarditis is an infection of the pericardium with tubercle bacilli that features different pathological stages and is the most common form of cardiac tuberculosis.

Epidemiology

Tuberculous pericarditis makes up for ≤4% of pericardial disease in developed countries but is the major cause of pericardial effusions in developing countries where TB is endemic and by far the most frequent cause of pericardial effusions in HIV patients ^1-4. Tuberculous pericarditis is found in all ages and men are more frequently affected than women ¹.

Risk factors

Risk factors for tuberculous pericarditis are ¹:

• immunosuppression
• HIV/AIDS
• countries in which tuberculosis is endemic
• chronic kidney disease

Associations

• tuberculous pericarditis is associated with tuberculosis elsewhere

Clinical presentation

Clinical symptoms can be insidious and non-specific including fever, fatigue, night sweats and weight loss as well as chest pain, dyspnea and cough. On the ECG, non-specific ST-segment and T-wave changes may be seen ^2,3.

Clinical manifestation might also differ subject to the stages ^2,3: 

• dry stage (least common)
  • chest pain and pericardial friction rub
  • widespread ST-segment elevation
  • no pericardial effusion
• effusive stage (most common)
  • compressive pericardial fluid causing signs and symptoms of heart failure
  • additional coexisting visceral constriction causing an effusive-constrictive pattern
• adsorptive and constrictive stage
  • constrictive symptoms or symptoms of left and right-sided heart failure including dyspnea, orthopnea, fatigability, ascites and peripheral edema

Complications

Complications of tuberculous pericarditis include ^1-4:

• cardiac tamponade
• pericardial constriction
• hepatic congestion
• cardiac arrest and death

Pathology

Tuberculous pericarditis can be d categorized into the following pathological stages ^2,3:

• dry stage
  • predominant fibrinous exudation, leukocytosis and abundant mycobacteria
• effusive stage
  • lymphocytic exudates with serosanguineous effusion
• adsorptive stage
  • absorption of effusion and organization of the granulomatous caseation
  • pericardial thickening due to fibrin deposition and collagen formation
• constrictive stage
  • constrictive scarring of the fibrosing visceral and parietal pericardium
  • pericardial calcifications with cardiac encasement and impairment of diastolic filling

Diagnosis is considered definite on detection of tubercle bacilli in the pericardial fluid or and/or on the pericardial histology section or by the detection of caseating granulomas. 

Tuberculous pericarditis is considered probable if there is evidence of pericarditis with tuberculosis elsewhere in the body, a lymphocytic pericardial exudate with increased adenosine deaminase (ADA) activity or good response to antituberculous therapy ^2,3.

Other options for early diagnosis are the detection of unstimulated interferon-γ (uIFN-γ) levels or lysozyme levels in the pericardial exudate ^1,3,4.

Etiology

The spread of tubercle bacilli to the pericardium can happen in the following ways ^2-4:

• retrograde lymphatic spread 
• hematological dissemination
• direct contiguous spread (least common)

Radiographic features

Imaging characteristics of tuberculous pericarditis are also subject to the stage and include ²:

• signs of pericarditis without effusion in the dry stage
• serosanguineous pericardial effusion in the effusive stage
• pericardial thickening and thick fibrinous fluid in the absorptive stage
• pericardial thickening, possibly calcification, no effusion, septal flattening and other features of pericardial constriction in the constrictive stage

Plain radiograph

Chest x-ray might show an abnormal cardiac silhouette and pleural effusions ³.

Echocardiography

Echocardiography is the first-line imaging modality in the diagnosis and monitoring of therapy in the setting of acute pericarditis. It can identify pericardial effusions possibly with fibrinous strands as well as complications, such as cardiac tamponade or impaired diastolic function indicating pericardial constriction ^2,3.

CT

CT will demonstrate pericardial effusion, pericardial thickening and enhancement. Additionally, it might reveal other organ involvement e.g. pulmonary tuberculosis as well as mediastinal lymph node involvement ³.

MRI

MRI is an adjunctive imaging modality for pericarditis and is done if echocardiographic findings are ambiguous or if myocardial involvement is suspected. MR imaging findings include the following ^2,3:

• pericardial thickening
• pericardial edema
• heterogeneous pericardial effusion
• pericardial enhancement

Radiological report

The radiological report should contain a description of the following:

• pericardial enhancement, pericardial effusion, pericardial thickening
• cardiac volumes and measurements
• ventricular wall motion abnormalities including abnormal septal motion or septal bounce
• myocardial involvement or signs of myocarditis
• other organ involvement and extent

Treatment and prognosis

Standard antituberculous management is not different from extrapulmonary tuberculosis and consists of rifampin, isoniazid, pyrazinamide and ethambutol for the first two months followed by rifampin and isoniazid for another four months ¹. 

Pericardiocentesis is the treatment of choice for alleviating symptoms from pericardial effusion/cardiac tamponade and is an important step for securing the diagnosis ².

Differential diagnosis

Conditions mimicking the radiological appearance of tuberculous pericarditis include ¹:

• purulent pericarditis
• neoplastic pericarditis

See also

• cardiac tuberculosis