Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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March 27, 2014
Tuberculous Meningitis
- Tuberculous meningitis (TBM) is the most common form of intracranial tuberculosis.
- Most common clinical manifestations include fever, headache, vomiting, and neck stiffness. Seizures, focal neurological deficits, stupor, and coma may be seen in late stages.
- CSF culture for acid-fast bacilli (AFB) and CSF polymerase chain reaction (PCR) are confirmatory tests for the diagnosis of TBM. Noninvasive imaging in an appropriate clinical setting helps suggest the diagnosis and evaluate for any complications.
- CNS involvement is seen in 15% of TB patients with AIDS, as compared to 5% of patients without AIDS.
- Key Diagnostic Features: Abnormal leptomeningeal enhancement, especially involving the basal cisterns. Intraparenchymal tuberculomas may be seen.
Complications include hydrocephalus, vasculitis, infarcts (especially basal ganglia), and cranial neuropathies.
- Mechanism for basal meningitis: Rupture of subependymal of subpial granulomas into the CSF or hematogenous spread to leptomeninges. A gelatinous exudate typically forms in the basal cisterns.
- Mechanism for infarcts: The exudate in the basal cisterns results in spasm and arterial thrombosis affecting primarily the perforating arteries.
- DDx: Pyogenic and fungal meningitis, CNS lymphoma, neurosarcoidosis, carcinomatous meningitis
- Rx: Anti-TB treatment
