Extrapulmonary Tuberculosis- A Diagnostic Conundrum!
Introduction: Tuberculosis continues to be the ninth leading cause of death worldwide. Pulmonary tuberculosis [PTB] being an infectious form of the disease receives greater attention & significance; while, the silent forms of disease like latent tuberculosis infection [LTBI] or extrapulmonary [EPTB] form of disease remains as the most neglected ones for reasons well known. Exact data on the disease burden from developing countries is missing due to the existing poor reporting system by both the patient and health care services.
Aim: To know the burden of the disease in a tertiary care hospital of India. To study the clinical trends in the disease, and the utility of various diagnostic modalities in diagnosis of the same. To identify the Mycobacterial species and perform drug susceptibility test.
Materials and Methods: A cross sectional study was carried out for a period of two years. A total of 147 samples were received and tested for extrapulmonary tuberculosis using a combination of bacteriological, cytological, histological and biochemical techniques to achieve proper diagnosis of EPTB.
Results: Bacteriologically, 26% of the specimens were positive for EPTB. Mycobacterial culture positivity was noted in 18%. Smear by Ziehl Nielsen stain was positive in 9%. Young adults and females predominated the study group and positive cases. A combination of culture media both solid and liquid maximized the yield of Mycobacteria. Lymph node tuberculosis was found to be the predominant type followed by others. Fifteen percent of the strains were found to be resistant to the first line drugs used in treatment of tuberculosis. Cytology and biochemical findings were found to be less specific in diagnosis of extrapulmonary tuberculosis. Rapid immuno chromatographic test called MPT64 Antigen test was very useful for presumptive identification of M.tb complex with reported sensitivity and specificity of 99% and 100%.
Conclusion: Extra pulmonary tuberculosis is seen in a substantial number of the symptomatic patients. Hence, attention should be paid towards its proper and early diagnosis followed by rational management, as if neglected may lead to associated complications and sequalae. Use of combination of media and methods enhances the diagnostic sensitivity. Further research is needed to evaluate specific reasons for why the disease is more common in young adults and females. It is wiser to read cytology and biochemical findings in light of bacteriological results as alone they are less specific. Resistance is emerging to anti tuberculosis drugs even in extra pulmonary form of disease. Hence the use of anti-tuberculosis drugs has to be justified as per the laboratory results for drug susceptibility test.
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Department of Microbiology, Ayaan Institute of Medical Sciences, Moinabad, Telangana, India.
Department of Pulmonology, Deccan College of Medical Sciences, Hyderabad, India.
Department of Pathology, Osmania Medical College, Hyderabad, India.
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