Background: Tuberculosis is one of the most common causes of pericardial effusion in the Philippines. The early diagnosis of tuberculosis among patients with pericardial effusion remains elusive to this date. Polymerase Chain reaction, a technique for amplifying small amounts of DNA when only small amount of cells are available, can amplify "fingerprint" strains of M. tuberculosis DNA in pericardial fluid with excellent specificity. This study was conducted to describe the role of Mycobacterium tuberculosis polymerase chain reaction (PCR) in the early .diagnosis of TB in patients with moderate to massive pericardial effusion by comparing it to existing diagnostic standards.
Methods and Results: Twenty-three subjects with moderate to massive pericardial effusion were included in this study. Majority were males with an average age of 40.2 ± 15.2 yrs. The average widest diameter of pericardial fluid by 2DED was 3.7 ± 1.3 cm before pericardiocentesis/ pericardiostomy, with 77% of the subjects had RA collapse and 64% had RV collapse on presentation. All pericardial fluid specimen tested were exudative based on Light's criteria. Cytological analyses were done on 19 subjects with 42% had findings characteristic of both acute and chronic inflammation. Five subjects had findings suggesting malignancy. Nine subjects had documented PPD results and two tested positive. All AFB smears done at the Philippine Heart center and Lung center of the Philippines showed negative results. Four out of 22 subjects had positive MTB cultures. Two of the subjects had a positive pericardial biopsy result for tuberculosis. Ten out of 23 subjects had their PCR done with a positive result in only one of the subjects. All of the specimens that tested negative for PCR also had negative results on MTB culture and pericardial biopsy.
Conclusion: AFB smear appears to have a limited use in pericardial fluid analysis. The role of PCR-TB in the early diagnosis of PTB cannot be fully assessed in this study. The lack of subjects with positive PCR result prevented us from giving any definite conclusion. PCR-TB seemed to correlate well with MTB culture and pericardial biopsy. All of the subjects who had a negative PCR-TB also had negative TB results on their culture and biopsy. TB culture and pericardial biopsy appear to complement each other, with the latter having the advantage of an earlier result and the potential to show other diagnosis aside from TB. The routine use of AFB smear and routine determination of serum and pericardial LDH and protein should be looked into.