Tubercular Meningitis (TBM)
Tubercular meningitis is a serious complication of childhood tuberculosis. It usually occurs secondarily to primary infection with tuburculosis. It may appear within one year of primary infection with tuberculosis and may lead serious disabling neurological sequelae.
The tubercular meningitis result due to hematogenous spread from primary leison. A submeningial tuberculoma may form which discharges tubercle bacilli in the subarachnoid space. The bacilli proliferate and cause perivascular exudation followed by caseation, gliosis and giant cell formation.
The meningial surface is covered with yellow greyish tubercles, usually along the course of the vessels which are more numerous in temporal lobe and along the course of middle cerebral artery. The ventricles get dilated resulting in obliteration of subarachnoid space and the arachnoid villi leading to increase in formation of cerebrospinal fluid. The foramina also get blocked with gelatinous exudate which interferes with CSF circulation and causes hydrocephalus. There is cereberal oedema which results in tuberculous encephalopathy.