Patient initially had headaches and vomiting. However, at the time of the scan the patient had been admitted with altered sensorium.
There is moderate dilatation of both the lateral and third ventricles. Also seen is slight dilatation of the fourth ventricle. There are periventricular hyperintensities on the T2W images. On the contrast enhanced images there is significant enhancement in the basal cisterns and sylvian fissures and along the surface of the brainstem.
CNS tuberculosis occurs in 2% to 5% of all patients with TB and in 10% of those with AIDS-related TB. CNS tuberculosis may manifest as tuberculous meningitis, abscess, cerebritis, and/or tuberculoma/s. Pulmonary TB is often seen in 25% to 80% of patients with CNS TB.
Pathogenesis: |
Rupture of subependymal/subpial granulomata into the CSF.
Penetration of the meningeal vessel walls by hematogenous spread - GI/Pulmonary.
As a result the basal meninges are involved and thick exudates are found in the basal cisterns. Coursing arteries (especially the MCA and it's branches) get involved directly or by reactive endarteritis obliterans. As a result spasm and intimal changes ending in thrombosis and infarction ensue.
Patients may present with fever, headaches, altered mental status and meningeal signs.
On MRI: |
Enhancement of the meninges, especially in the basal cisterns.
Obliteration of the cisterns/sulcal spaces by exudates on the non-enhanced scans.
Communicating hydrocephalus (occasionally-obstructive, due to parenchymal lesions or granulomatous ependymitis).
May find infarcts-especially in the basal ganglia.
Meningeal disease and non-enhancing lesions are commonly encountered in HIV positive patients.
| Differential Diagnosis: |
Leptomeningeal carcinomatosis.
Sarcoid.
Lymphoma/Leukemia.
Please see braintf2 and braintf15
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