The Utility of CSF Xpert MTB/RIF in Diagnosis of Tubercular Meningitis in Children.

Abstract

To determine the utility of CSF Xpert MTB/RIF (GeneXpert) in diagnosis of tubercular meningitis in children in the age group of 2 mo to 12 y. This hospital based prospective observational study was conducted at Department of Pediatrics, Karnataka Institute of Medical Sciences (KIMS), Hubli from December 2015 through November 2016. All children with clinically suspected tuberculous meningitis (TBM) were included in the study. These children underwent a detailed history taking, clinical examination, blood investigations, lumbar puncture and CT brain. Cerebrospinal fluid (CSF) samples were sent for CSF GeneXpert examination. Statistical analysis was done using IBM SPSS Statistics Version 20. A total of 28 children were enrolled in the study. Six (21.4%), 4 (14.3%) and 18 (64.3%) cases were definite, probable and possible TBM cases respectively. Most common age group affected was <5 y (83.33%) with median age 2.5 y (IQR 4.875). Male:female ratio was 1.5:1. CSF GeneXpert was tested positive in 6 cases (21.4%). The sensitivity of the test against the clinical scoring (>/=10) was 46.15% (95% CI, 19.22-74.87) and specificity was 100% (95% CI, 78.20-100). There was a significant association between CSF GeneXpert and Mantoux test (P= 0.002), CSF cell type >50% lymphocytes (P= 0.005) and CSF protein >100mg/dl (P= 0.025) along with CT hydrocephalus (P= 0.021), granuloma (P= 0.009) and basal exudates (P= 0.025). None of the cases were tested smear positive for acid-fast bacilli (AFB). CSF GeneXpert is superior to smear for AFB in TBM.