Heterogeneity in Clinical Manifestation of Tuberculosis and Comparison between Different Diagnostic Modalities: A Cross-sectional Study
Authors: Das Upasana , Gauda Kalyani Prava , Mohanty Indrani , Bal Atanu Kumar , Hotta Sasmita 
Published: December 2024

Introduction: Infection with tuberculosis is a worldwide health concern. Nearly every organ in the body can be affected by Extrapulmonary Tuberculosis (EPTB). A simple diagnosis of Pulmonary Tuberculosis (PTB) can be made using radiography and a positive sputum test. On the other hand, diagnosing EPTB is difficult due to the peculiar presentation of the lesions, which are paucibacillary and exhibit varied sensitivity and specificity in different diagnostic tests across different infected tissues.

Aim: To analyse the varied clinical presentations of tuberculosis infection and to assess several diagnostic techniques for detecting pulmonary and extrapulmonary tuberculosis in reference to the Composite Reference Standard (CRS).

Materials and Methods: The present cross-sectional study was carried out in the Department of Pathology and Microbiology, PRM Medical College and Hospital (in the tuberculosis endemic zone of Baripada), North Odisha, India, between April 2018 and November 2022. Clinical presentations included lumps, ulcers, inflammation and lesions resembling neoplasia. All age groups of patients suffering from pulmonary and extrapulmonary tuberculosis were included. A total of 400 tuberculosis cases were detected. Fine needle aspiration was performed on the lesions after considering the patient’s age, gender, lesion location and relevant radiological studies. Biopsy samples were handled in a similar manner. To detect mycobacterial nucleic acid, all 400 cytology cases and biopsy samples were processed using the Cartridge-based Nucleic Acid Amplification Test (CBNAAT) and stained with Ziehl-Neelsen (ZN) stain for Acid-fast Bacilli (AFB) identification. A CRS was defined as the presence of bacilli in CBNAAT and/or AFB along with morphologic evidence such as caseating granulomas. To assess sensitivity and diagnostic effectiveness, CRS was used in conjunction with procedures from cytology, histopathology, AFB detection and CBNAAT. The p-value for McNemar’s test was less than 0.05, indicating statistical significance across all analyses.

Results: The analysis revealed a male-to-female ratio of 1:1.02, with more females than males over the age of 20 years affected. Pulmonary tuberculosis cases were 39 (9.75%), while extrapulmonary TB cases were 361 (90.25%). The largest percentage of extrapulmonary tuberculosis cases (n=134, 33.5%) involved lymph nodes, with skeletal involvement following closely behind (n=64, 16%). Mycobacterium tuberculosis adversely affected nearly every organ in the body. The most prevalent pattern in histology was necrotising granulomatous inflammation, observed in 85 (69.6%) patients. Similarly, a type II pattern (epithelioid granuloma with caseous necrosis) was seen in 166 (59.7%) cytosmear cases. The sensitivity and diagnostic accuracy of four tests were assessed using the CRS; favourable results were obtained for FNAC (72.2%), histological examination (100%), ZN staining (20.5%), and CBNAAT (85.6%). With a diagnostic accuracy of 92.8%, CBNAAT outperformed FNAC and histology, which both achieved 86% accuracy.

Conclusion: The prevalence of pulmonary and extrapulmonary tuberculosis is extremely high among the people of North Odisha. The present study suggests a combined approach of understanding clinical presentation, conducting pathological investigations, and detecting bacilli to recognise atypical presentations of EPTB at an early stage, given the restricted resources and facilities in peripheral hospitals.