Clinical, Laboratory and radiologic features of Tuberculous Meningitis in Children at the University Teaching Hospital, Department of Paediatrics and Child Health

Abstract

Introduction: Tuberculosis (TB) is one of the top 10 reasons for admission in the University Teaching Hospital(UTH), Department of Paediatrics, accounting for 4 -8 % of all admissions. The relative incidence of tuberculous meningitis (TBM) in developing countries has been reported to range from 7-12% of all cases of TB. Because TBM can mimic other meningitides or common illnesses like cerebral malaria, diagnosis is often delayed, resulting in poor outcome. Objective: To describe the clinical, laboratory and radiological features of TBM in children admitted to the UTH department of Paediatrics and Child health. Method: Prospective descriptive case series carried out from February 2007 to November 2007. Twenty one children were recruited. Clinical case definition of TBM was based on the following: Abnormal neurologic signs and/or symptoms, and 2:2 of the following: 1.History of adult source case with TB who had contact with child 2.Presence of tuberculin skin test (TST) reaction ^10 mm of induration in HIV un-infected, or > 5 mm of induration in HIV infected children 3.CSF abnormalities without evidence of other infectious cause 4.A chest radiograph consistent with primary TB infection, such as miliary picture, hilar lymphadenopathy or mediastinal adenopathy 5.Failure of sustained response to antibiotic and/or anti-malarial treatment Clinical, laboratory and radiologic features of the 13 children with TBM were evaluated and documented for the study. The 8 non-TBM children were excluded from the analysis. Results: Of the 13 children, 7 (53.8%) were male and 6 (46.2%) were female, the majority of whom (69.3%) were less than 43 months old. All the children had history of fever, 53.8% had TB contact, 69.2% had weight loss, 92.3% had meningeal signs and 46.2% were TST positive. More HIV negative children test TST positive than HIV negative children (55.6% versus 25%). Eleven (92.3%) of the children had ESR >50mm/hr. Four (30.8%) of the children were HIV positive. The chest radiographs were abnormal in 6/12 (50%) of the children. Gastric lavage was negative for Acid and Alcohol Fast Bacilli (AAFB) in all children tested. CSF protein was elevated in 10 (76.9%) patients and CSF to blood glucose was reduced <0.6 in 10 (76.9%) children. Both CSF microscopy and Mycobacteria Growth Indicator Tube (MGIT) culture yielded no AAFB. All children had at least two courses of antibiotics before Anti Tuberculous Treatment was commenced. Conclusion: Definitive diagnosis of TBM continues to be difficult as none of the children had tubercle bacilli isolated from sputum or CSF. Moreover, abnormal CSF protein and sugar, positive TST and failure of adequate response to initial antibiotics were the major criteria used for the diagnosis of probable TBM in UTH.