Value of CT scan in the diagnosis of meningitis.

OBJECTIVE

To study the diagnostic test characteristics of computed tomography (CT scan) in differentiating tuberculous (TBM) and pyogenic (PM) meningitis.

DESIGN

Prospective diagnostic test evaluation.

SETTING

Teaching hospital.

METHODS

Children beyond 1 month of age admitted with meningitis were enrolled prospectively and CT scan done. Results of CT scan were compared with predefined gold standards for the diagnosis of either TBM or PM.

RESULTS

CT scan was performed in 154 patients with meningitis. Of these 94 were TBM, 52 had PM and 8 were indeterminate and excluded from analysis. Basal enhancement, ventriculomegaly, tuberculoma and infarction were all significantly more common in the TBM group, while subdural collections were seen more in the PM group. The highest sensitivity (89.2%) and specificity (100%) for diagnosis of TBM were found for basal enhancement or tuberculoma or both.

CONCLUSIONS

CT scan can be used to effectively distinguish TBM and PM.