Tuberculous pericarditis: Molecular methods to aid early diagnosis and treatment to avoid sinister outcomes

Objectives Tuberculous pericarditis (TP) can have a varied clinical picture and is a differential diagnosis in non-self-limiting pericarditis. Diagnosing TP early is challenging due to the low concentration of mycobacteria in pericardial fluid. An early diagnosis can expedite treatment and response. The present paper summarises laboratory experience with the diagnosis of TP. Material and Methods The study included patients with a clinical suspicion of TP (2018-2022). Pericardial fluid samples were analyzed using microscopy (Ziehl Neelsen staining or ZN), GeneXpert MTB/RIF (Gx), TB PCR, and liquid culture (mycobacteria growth indicator tube [MGIT 960]). Not all samples could be tested using every method. The NALC-NaOH method was used for sample processing. Blood samples of the patients were tested for lymphocyte count and erythrocyte sedimentation rate (ESR). The samples were also tested for adenosine deaminase (ADA) using a commercial kit. Statistical analysis was performed using Stata 16.0 software, with p-values calculated using the Wilcoxon rank-sum test. Results In all, results from 230 patients were included for analysis. Six patients detected positive for TB, with a mean age of 48 years, and 4 patients were male. None of the samples tested positive by ZN staining, 5/6 samples were positive by molecular techniques (2 by Gx and 3 by PCR), and the culture was positive by MGIT in one person. Neither serum ADA enzyme values nor ESR were significantly associated with TP. Of six positive patients, two had normal lymphocyte counts, while the rest of the four patients had a low lymphocyte count. Sixteen patients had high lymphocyte counts but were not positive for TB. Two of the six TB-positive patients succumbed to the disease; one of these two patients was suffering from cancer as well. Two were lost to follow-up, while 2 others recovered. Conclusion Molecular methods contributed to early diagnosis. Lymphocyte count, serum ADA levels, and ESR were not found to be significantly associated with TP. Hence, we advocate the use of molecular methods for early diagnosis of TP, which will also reduce sinister outcomes like mortality.