Original Article
Yield of pleural biopsy in different types of tubercular effusions

https://doi.org/10.1016/j.ijtb.2020.07.023Get rights and content

Highlights

  • Role of pleural biopsies in the diagnosis of tubercular effusions.

  • Role of GeneXpert/Culture in a pleural biopsy specimen.

  • Yield of GeneXpert/Culture in simple and tubercular effusions.

Abstract

Introduction

The yield of mycobacteria is shown to be very low in pleural effusions as it is a pauci-bacillary disease. The present study looked at the yield of mycobacterium tuberculosis (MTB) in terms of GeneXpert for acid fast bacilli (AFB) and culture using a medical thoracoscopy guided biopsy and analysed whether the yield increases in more complicated effusions.

Materials and methods

This is a retrospective analysis of patients who underwent medical thoracoscopy for tubercular pleural effusions at our institute over the last 5-years. Patients who had no or minimal thin septations were considered as simple effusions and were subjected to semi-rigid thoracoscopy (n = 61). While patients who had multiple loculations and thick septations were considered as complicated effusions and were subjected to rigid thoracoscopy (n = 64). We considered granuloma on a biopsy as the standard for diagnosis of Tuberculosis (TB). Xpert MTB/RIF and The BACTEC MGIT was used for culture.

Results

Out 125 patients with granulomatous inflammation on biopsy, 56 (44.8%) were positive for either GeneXpert or culture for MTB. Only GeneXpert was positive in 43 and only culture was positive in 13. Amongst 61 patients with simple effusion, 14 had either GeneXpert for AFB or AFB culture being positive and 9 out of these patients had GeneXpert for MTB detected on biopsy sample. Only culture was positive in 5 patients. In complicated pleural effusion group either GeneXpert or culture for mycobacterium was positive in 42 (65.6%) out of 64 patients. Only GeneXpert was positive in 34 and culture alone was positive in 8 patients.

Conclusion

The yield of MTB increases as the pleural effusion becomes more complicated. GeneXpert in a biopsy sample is a useful marker for MTB yield especially in a complicated effusion.

Introduction

Tuberculosis [TB] is the most common cause for exudative pleural effusions in areas where it is endemic. While it is the second most common form of extrapulmonary tuberculosis overall.1 Tubercular pleural effusions are usually considered to occur as a part of primary tuberculosis, but in adults it is shown to occur due to reactivation as well.2,3 Tubercular pleural effusion most often occur as a result of delayed hypersensitivity reaction to mycobacteria or its antigens if it occurs in association with primary tuberculosis.4 In reactivation it is usually an empyema and results secondary to rupture of an adjacent cavity or a paratracheal lymphnode, paravertebral abscess, osteomyelitis of adjacent bones or due to transdiaphragmatic spread. Tubercular empyema though severe are said to be less common than the simple effusion.4 The Gold standard for diagnosis of Tubercular pleural effusion is by the demonstration of mycobacterium tuberculosis in the sputum, pleural fluid, or pleural biopsy specimens.5 But microscopy of the pleural fluid for acid-fast bacilli is positive in only around 5% and mycobacterial culture is positive in about 24% of cases of TB effusions. This is probably due to the paucibacillary nature of the disease.6

GeneXpert for MTB has been validated in the diagnosis of smear positive PTB with a very high sensitivity (98%) and specificity (98%),7,8 but its role in smear-negative pulmonary tuberculosis and tubercular pleural effusions is still evolving.9 Few studies from sub-continent have shown a very low sensitivity in the pleural fluid and biopsy samples. Studies have shown that the biopsy obtained using medical thoracoscopy increases the yield in tubercular pleural effusions.10 Our study looked into the yield of thoracoscopy guided pleural biopsies in tubercular pleural effusions in terms of GeneXpert and mycobacterial culture. In addition, we also analysed the difference in the yield of MTB in biopsies from simple and complicated pleural effusion using medical thoracoscopy (semi-rigid and rigid thoracoscopy).

Section snippets

Materials and methods

Medical thoracoscopy data of patients over last 5 years was collected, and retrospective analysis was done in Tubercular pleural effusions. Granulomatous inflammation on pleural biopsy was taken as the standard for the diagnosis of tuberculosis in our study. Data of 125 patients was analysed. Medical thoracoscopy was performed in the department of pulmonary medicine at Narayana Health City, Bangalore, India, between May-2015 and march-2020. Patients who had no/or minimal septations and no

Results

A total of 125 patients who were subjected to medical thoracoscopy had granulomatous lesions. 91 patients were male and 34 were female. Mean age was 42.3 ± 16.4 years and the mean ADA was 49.87 ± 19.0 iu. The basic demographics are presented in Table 1.

Among 61 patients with simple effusions who underwent semi-rigid thoracoscopy, 51 were male and 10 were female. The mean age was 48.3 ± 16.2 years. The mean ADA was 59.18 ± 26.7. Sixteen (33.3%) patients had diabetes mellitus (DM), 7 patients had

Discussion

Immune response to the MTB leads to the formation of granuloma in various tissues including the lung. The delicate balance between immune system and the mycobacterium keeps the growth of the bacteria under a check. Any disturbance in this balance leads to formation of caseation necrosis, disintegration of granuloma and release of MTB from the center to the adjacent tissues or spaces like pleural cavity. This results in an inflammatory response in the adjoining structures like pleura and

Conclusions

The yield of MTB increases as the pleural effusion becomes more complicated. GeneXpert in a pleural biopsy is a useful marker for MTB yield, especially in a complicated effusion as the drug resistance for MTB is on the rise. Rigid thoracoscopy should be considered in a complicated effusion as it has a good diagnostic yield as well as therapeutic benefit.

Source of funding

No funding received for this study.

Declaration of competing interest

All authors have none to declare.

Acknowledgements

The authors would like to acknowledge Dr. V.M. Annapandian, for his contribution in editing this manuscript. Dr. Tiyass Sen Dutt and Dr. B.R. Harish for assisting in procedures.

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Cited by (0)

c

Both authors contributed equally to the paper and procedures.

d

Equally contributed in semi-rigid pleuroscopy.

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