1. CASES OF PLEURAL EFFUSION (n=56)
Application of CBNAAT (Xpert MTB/RIF Assay) in new smear negative presumptive extra-pulmonary Tuberculosis Patients
Dr. Neha Garg1, Dr. Urvinderpal Singh2, Dr. Vishal Chopra3, Dr. Bharat Bhushan3, Dr. Jawahar Lal Joshi4, Dr. Vinay Mohan5, Dr. Shailly1, Dr. Abdur Razack1
1. Junior Resident, 2. Professor, 3. Associate Professor, 4. Assistant Professor, 5. Senior Resident, Department of Pulmonary Medicine, Government Medical College, Patiala.
INTRODUCTION:
Extra pulmonary TB disease constitute 10-15% of tuberculosis burden in India.1 Delay in the diagnosis results in increased morbidity and mortality. Application of Cartridge based nucleic acid amplification testing (CBNAAT) has resulted in early diagnosis in various studies.
DISCUSSION:
FNAC offers a feasible and safe option for specimen collection 2. Cytology and smear staining for AFB helps in diagnosis. Conventional microbiological culture are available at selected centres, is a cumbersome process and take 6 weeks for results to be available.3
CONCLUSION:
In cases of Cold Abscess, those patients who were MTB not detected, ATT can be deferred till culture result are available. While in case of pleural effusion who were CBNAAT MTB not detected, needs clinical correlation regarding initiation of empirical ATT. In Empyema the role of CBNAAT is enhanced in excluding tubercular empyema from other empyema’s so as to decide regarding start of antitubercular treatment on time in such cases .
OBJECTIVE:
The objective of this study is to assess the role of CBNAAT in new smear negative presumptive extra pulmonary TB (cold abscesses (breast, axillary, cervical, paraspinal, shoulder & etc.) and pleural effusion), patients.
METHOD:
This was a prospective study conducted at Chest and TB Hospital Patiala in which 105 treatment naïve patients (49 with cold abscess and 56 with pleural effusion) who were smear negative for AFB were included. Cold abscess and pleural fluid was aspirated and sent for CBNAAT. Specimens that were CBNAAT MTB not detected were subjected further to liquid culture. Mycobacterial Growth Indicator Tube, MGIT).
KEY WORDS:
Extra pulmonary TB, smear negative, CBNAAT, Anti tubercular Treatment, Cold Abscess & Pleural Fluid
Cold Abscess 49
MTB Detected 33
RIF Sensitive 32
RIF Resistance 1
MTB Not Detected 16
Liquid Culture Neg 15
Liquid culture Pos
CBNAAT
RESULT:
Out of 49 patients with cold abscess 33 were CBNAAT MTB detected , of which 32 were sensitive to Rifampicin while one was resistant. 16 Patients who were CBNAAT MTB not detected , their samples were subjected further to liquid culture of which one showed positive growth . Among 56 patients of pleural effusion, 15 were CBNAAT MTB detected, of which 12 were sensitive and 3 resistant to rifampicin. 41 patients who were CBNAAT MTB not detected, no sample showed growth of MTB on liquid culture
REFERENCES:
Vadwai V, Boehme C, Nabeta P, Shetty A, Alland D, Rodrigues C. Xpert MTB/RIF: a new pillar in diagnosis of extrapulmonary tuberculosis? J Clin Microbiol. 2011;49(7):
Wright C.A., et al Fine-needle aspiration biopsy: a first-line diagnostic procedure in paediatric tuberculosis suspects with peripheral lymphadenopathy? Int. J. Tuberc. Lung Dis. 13:
WHO 9 August 2010, accession date, policy guidance on drug-susceptibility testing of second line antituberculosis drugs. WHO, Geneva, Switzerland: HTM TB eng.pdf.
CASES OF PLEURAL EFFUSION (n=56)
Pleural Fluid (n=42)
Pleural Pus (n=14)
Negative
Positive
CBNAAT 34 8 7
Liquid Culture
Rifampicin Resistance
Neg 1
neg 2
 CASES OF COLD ABSCESS (n=49)
Positive
Negative
CBNAAT 33 16
Liquid Culture 15
Rifampicin Resistance 1
nil