Affiliations: Department of Pediatrics, Vardhamaan Mahavir Medical
College and Safdarjang Hospital, New Delhi, India | Department of Microbiology, Vardhamaan Mahavir Medical
College and Safdarjang Hospital, New Delhi, India
Note: [] Correspondence: Dr. Mukul Aggarwal, MBBS, Department of
Pediatrics, Vardhamaan Mahavir Medical College and Safdarjang Hospital, 110029,
New Delhi, India. Tel.: +91 9868449649; E-mail: mukulmamc@gmail.com
Abstract: The diagnosis of Central Nervous System tuberculosis (CNS TB) had
been always an enigma as yield of Mycobacterium tuberculosis in cerebrospinal
fluid (CSF) is very low and diagnosis mainly rested on combination of clinical,
CSF analysis and radiological findings. We attempted to find whether 16s rRNA
primer based real time Polymerase chain reaction (PCR) aids in diagnosis of
tubercular meningitis (TBM) and tuberculoma. Literature is flooded with newer
techniques for the diagnosis of neuro-tuberculosis by real time PCR. But no
clear cut guidelines are available about their role. 40 cases of tubercular
meningitis, diagnosed on basis of Modified Ahuja Criteria and 40 controls were
included in this prospective study. All patients were evaluated clinically and
investigated in detail including cerebrospinal fluid analysis, Acid Fast
Bacilli staining, culture for TB by Bac T Alert 3-D system,16s rRNA real time
PCR assay, chest X ray, computed tomography scans of head, contact survey using
chest X-ray, Mantoux test and hemogram. Comparative analysis of real time PCR
were done in control group vs. cases of TBM diagnosed on the basis of Modified
Ahuja criteria. Results: CSF for tuberculosis by real time PCR was positive in
26/40 cases (65%) of TBM, as against 2/40 controls. Keeping the CSF culture as the gold standard its sensitivity is 62.50 (95% confidence
intervals- 54.7, 85.2), specificity is 77.40 (95% confidence intervals- 54.7, 85.2), positive
predictive value is 46.15 and negative predictive value is 88.89. Modified
Ahuja criteria can serve as useful tool in diagnosis. CSF analysis by real time
PCR has shown better sensitivity and quicker results than culture. However, it
cannot be recommended alone as it was negative in about a third of cases. But
its significance is underlined in early diagnosis and as an adjunct to
culture.
Keywords: Real time polymerase Chain reaction, neurotuberculosis, cerebrospinal fluid analysis, tubercular meningitis, tuberculoma
