Tuberculous meningitis. Tuberculous meningitis is an uncommon but potentially devastating form of tuberculosis. Current antituberculous drugs are highly effective when treatment is initiated early, before the onset of altered mentation or focal neurologic deficits. Because the clinical outcome depends greatly on the stage at which therapy is initiated, early recognition is of paramount importance. Patients with the meningoencephalitis syndrome and CSF findings of low glucose levels, elevated protein levels, and pleocytosis should be treated immediately if there is evidence of TB elsewhere in the body, or if prompt evaluation fails to establish an alternative diagnosis. Examination of CSF is the best diagnostic approach; with sufficient diligence, serial AFB smears and cultures will usually yield positive results, even days after therapy has been started. The CT scan is an important and highly effective tool for the diagnosis and management of patients with TBM. In a patient with compatible clinical features, the combination of basilar meningeal enhancement and any degree of hydrocephalus is strongly suggestive of the diagnosis of TBM. Serial evaluation by CT scanning is useful for following the course of hydrocephalus and tuberculoma, particularly in reference to the need for, or response to, adjunctive therapy with corticosteroids and surgery. The decision to administer corticosteroids should be based on careful correlation of the clinical and radiographic features of the case. Surgical shunting should be considered early in the patient with hydrocephalus and symptoms of raised intracranial pressure. Tuberculomas are best treated medically, often in conjunction with corticosteroids where cerebral edema is believed to contribute to neurologic decline. The recommended chemotherapy regimen is isoniazid and rifampin in all patients, together with pyrazinamide for the first 2 months. 