Retrospective Cohort Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Surg. Apr 27, 2021; 13(4): 355-365
Published online Apr 27, 2021. doi: 10.4240/wjgs.v13.i4.355
Diagnosis of anorectal tuberculosis by polymerase chain reaction, GeneXpert and histopathology in 1336 samples in 776 anal fistula patients
Pankaj Garg, Ankita Goyal, Vipul D Yagnik, Sushil Dawka, Geetha R Menon
Pankaj Garg, Department of Colorectal Surgery, Indus International Hospital, Mohali 140507, Punjab, India
Pankaj Garg, Department of Colorectal Surgery, Garg Fistula Research Institute, Panchkula 134113, Haryana, India
Ankita Goyal, Department of Pathology, Gian Sagar Medical College and Hospital, Patiala 140506, Punjab, India
Vipul D Yagnik, Department of Surgery, Nishtha Surgical Hospital and Research Centre, Patan 384265, Gujarat, India
Sushil Dawka, Department of Surgery, SSR Medical College, Belle Rive, Mauritius
Geetha R Menon, Department of Statistics, Indian Council of Medical Research, New Delhi 110029, India
Author contributions: Garg P and Menon GR conceived and designed the study, collected and analyzed the data, revised the data, finally approved, and submitted the manuscript (Guarantor of the study); Goyal A and Yagnik VD collected and analyzed the data, revised the data, finally approved and submitted the manuscript; Dawka S critically analyzed the data, reviewed and edited the manuscript, finally approved and submitted the manuscript.
Institutional review board statement: The study was reviewed and approved by the Indus International Hospital-Institute Ethics Committee (reference number EC/IIH-IEH/SP5).
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: None of the authors have any conflict of interest. No grant or funding was received by any of the authors for the study.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author, Dr Pankaj Garg at drgargpankaj@yahoo.com. Participants gave informed consent for data sharing.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Pankaj Garg, MBBS, MS, Surgeon, Department of Colorectal Surgery, Indus International Hospital, Near Dera Bassi, Mohali 140507, Punjab, India. drgargpankaj@yahoo.com
Received: January 12, 2021
Peer-review started: January 12, 2021
First decision: February 11, 2021
Revised: February 11, 2021
Accepted: April 14, 2021
Article in press: April 14, 2021
Published online: April 27, 2021
Abstract
BACKGROUND

The association of tuberculosis (TB) with anal fistulas can make its treatment quite difficult. The main challenge is timely detection of TB in anal fistulas and its proper management. There is little data available on diagnosis and management of TB in anal fistulas.

AIM

To detect TB in fistula-in-ano patients were analyzed in different methods utilized.

METHODS

A retrospective analysis of different methods, polymerase chain-reaction (PCR), GeneXpert and histopathology (HPE), utilized to detect tuberculosis in fistula-in-ano patients, treated between 2014-2020, was performed. The sampling was done for tissue (fistula tract lining) and pus (when available). The detection rate of various tests to detect TB and prevalence rate of TB in simple vs complex fistulae were studied.

RESULTS

In 1336 samples (776 patients) tested, TB was detected in 133 samples (122 patients). TB was detected in 52/703 (7.4%) samples tested by PCR-tissue, in 77/331 (23.2%) samples tested by PCR-pus, 3/197 (1.5%) samples tested with HPE-tissue and 1/105 (0.9%) samples tested by GeneXpert. To detect TB, PCR-tissue was significantly better than HPE-tissue (52/703 vs 3/197 respectively) (P = 0.0012, significant, Fisher’s exact test) and PCR-pus was significantly better than PCR-tissue (77/331 vs 52/703 respectively) (P < 0.00001, significant, Fisher’s exact test). TB fistulas were more complex than non-tuberculous fistulas [78/113 (69%) vs 278/727 (44.3%) respectively] (P < 0.00001, significant, Fisher’s exact test) but the overall healing rate was similar in tuberculous and non-tuberculous fistula groups [90/102 (88.2%) vs 518/556 (93.2%) respectively] (P = 0.10, not significant, Fisher’s exact test).

CONCLUSION

This is the largest study of anorectal TB to be published. The detection of TB by polymerase chain-reaction was significantly higher than by histopathology and GeneXpert. Amongst polymerase chain-reaction, pus had a higher detection rate than tissue. TB fistulas were more complex than non-tuberculous fistulas but aggressive diagnosis and meticulous treatment led to comparable overall success rates in both groups.

Keywords: Anal fistula, Fistula-in-ano, Tuberculosis, Histopathology, Polymerase chain-reaction, GeneXpert

Core Tip: This is the largest study of anorectal tuberculosis (TB) to be reported. A total of 1336 tissue and pus samples were tested in 776 patients over 6 years. Polymerase chain-reaction, GeneXpert and histopathology were utilized to detect TB in these samples. Polymerase chain-reaction was more sensitive than histopathology and GeneXpert to detect TB in anal fistulas. This is the first study in which these three methods have been compared in the same cohort. Pus was more sensitive than tissue samples to detect TB. TB fistula had a significantly higher proportion of complex fistulas but timely diagnosis and treatment led to a high success rate in these fistulas.