Tuberculosis and Pericarditis
Pericardial tuberculosis is a complication of tuberculosis. The diagnosis for this condition can be difficult to establish and can be often delayed or missed, leading to serious complications such as constrictive pericarditis.
Pericardial tuberculosis can be seen with 1 to 2% patients suffering from primary tuberculosis. In the last decade, tuberculosis of the pericardium has been seen in immuno-compromised patients (HIV) in developed countries.
This condition can be fatal even with a correct diagnosis and treatment. The mortality rate in untreated acute effusive TBC pericarditis has been calculated to be around 85%.
This kind of Pericardial Tuberculosis is also difficult to diagnose because a definitive diagnosis requires a biopsy of the tissue or pericardial fluid aspiration that needs to be observed under the microscope for mycobacterium tuberculosis.
Pericardial Tuberculosis Clinical Presentation
Tuberculosis can begin with the symptoms of night sweats, fever and blood stained sputum along with a chronic cough. But tuberculosis of the pericardium can have many different clinical presentations.
These variable presentations can include:
- Acute pericarditis with or without cardiac effusion
- Cardiac tamponade
- Silent without any symptomatic presentation
- Large pericardial effusion with a relapsing course
- Toxic symptoms with persistent fever
- Acute constrictive pericarditis
- Sub-acute constrictive pericarditis (slower onset of symptoms)
- Effusive constrictive pericarditis
- Chronic constrictive pericarditis
- Pericardial calcifications
Diagnosis of Pericardial Tuberculosis
The mortality rate of pericardial tuberculosis is very high, therefore the importance of an accurate diagnosis is crucial. The diagnosis of PT can be made by many methods:
Perocardiocentesis: This also offers some value for diagnosis of pericardial tuberculosis as well. The pericardial fluid collected will contain high protein, high specific gravity and a high white cell count. Additionally PCR techniques can be used to identify the nucleic acids of mycobacterium tuberculosis in the fluid.
Pericardial biopsy: Identification of mycobacterium tuberculosis in the pericardial tissue. This can be done by taking a tissue biopsy of the pericardium. Pericardial biopsy enables rapid diagnosis with better sensitivity than pericardiocentesis. The identification of caseous granuloma in the pericardium is diagnostic as it may signal the presence of tuberculous bacteria in the vicinity.
Suggestive signs and symptoms: The presence of signs and symptoms of pericarditis in a patient who has documented/proven extracardial tuberculosis can strongly suggest the diagnosis of Pericarditis tuberculosa.
The tuberculin skin test: This usually which gives a fairly good idea about lung TB but is false negative in 25 to 30 % of the patients with Pericarditis Tuberculosa and it is false positive in 30 to 40% of the patients.
ELISPOT test: Recently a more specific test has been discovered called the enzyme-linked immunospot (ELISPOT) test. This test is more accurate than a tuberculin skin test. It can detect T cells that are specific for mycobacterium tuberculosis antigen.
Antibody titres: Pericarditis tuberculosa produces high titres of anti-myolemmal and anti-myosin antibodies in the sera.
Adenosine deaminase and interferon gamma: Elevated levels in the pericardial fluid are also diagnostic and provide a high specificity and sensitivity.
Treatment of Pericardial Tuberculosis
Multiple anti-tuberculous drug combinations of different lengths (3 months, 6 months, 9 months or 12 months) are used for the patient with Pericarditis Tuberculosa. Only those patients with a confirmed diagnosed of tuberculous pericarditis should be started with this type of therapy.
Repeated pericardiocentesis may be required to drain the pericardial effusion. Combining the standard anti-tuberculous drug therapy with steroid therapy can offer some benefit to reduce the risk of constrictive pericarditis. It can decrease the need for frequent pericardiocentesis. If constrictive pericarditis develops despite therapy, a pericardiectomy may be required to surgically remove the pericardium damaged due to pericardial tuberculosis.