Answer for BIR CoW 24 Mar 2024
Tuberculous Meningitis with Tuberculoma
Findings
Plain study shows diffuse effacement of sulcal space and perimesencephalic cisterns and obstructive hydrocephalus with periventricular seepage Well defined hypodense lesion noted in the left medial temporal region Contrast study shows diffuse leptomeningeal and perimesencephalic pial enhancement Left medial temporal lesion shows ring enhancement
Discussion
Tuberculous meningitis is the most common presentation of intracranial tuberculosis. It refers to infection of the leptomeninges. Tuberculous granuloma formation within cerebrum is the most common form of parenchymal tuberculosis. It is more frequently encountered in adolescents and adults. CECT brain can pickup tuberculous meningitis findings in appropriate clinical setting without the need for MRI. Pathophysiology Rupture of initial subependymal or subpial tubercule focus into subarachnoid space (after earlier haematogenous dissemination)into CSF - thick gelatinous exudate settles at base of brain along cisterns +sylvian fissure + along traversing vessels. Complications Communicating hydrocephalus due to blockage of basal cisterns by inflammatory exudate. Obstructive hydrocephalus - mass effect effect of tuberculoma causing obstruction of CSF flow. Ischaemic infarction in basal ganglia and internal capsule to vasospasm of penetrating vessels. Cranial neuropathy - extension of cisternal inflammation along traversing cranial nerves. Imaging features CT - iso or hypoattenuating meninges relative to basal cisterns and often homogenous contrast enhancement of meninges. MRI- Normal at unenhanced images at early stage. Distension of subarachnoid spaces. MRI - abnormal meningeal enhancement on gadolinium enhanced T1WI . abnormal enhancement of choroid plexus + ependymal lining. Non-caseating granuloma T1: iso- to- hypointense T2: hyperintense T1 C+ (Gd): homogeneous enhancement. Caseating granuloma T1: iso- to- hypointense with hyperintense rim T2:hypointense representing gliosis and abundant monocyte infiltration surrounded by vasogenic edema T1 C+ (Gd): homogeneous or ring-enhancement MR spectroscopy lipid-lactate peaks are usually elevated (86%)Caseating granuloma with central liquefaction T1: iso- to- hypointense with hyperintense rim T2:hypointense rim with central hyperintensity surrounded by vasogenic edema T1 C+ (Gd): ring enhancement Calcified granuloma T1: iso- to- hypointense T2: hypointense T1 C+ (Gd): no enhancement
Findings
Plain study shows diffuse effacement of sulcal space and perimesencephalic cisterns and obstructive hydrocephalus with periventricular seepage Well defined hypodense lesion noted in the left medial temporal region Contrast study shows diffuse leptomeningeal and perimesencephalic pial enhancement Left medial temporal lesion shows ring enhancement
Discussion
Tuberculous meningitis is the most common presentation of intracranial tuberculosis. It refers to infection of the leptomeninges. Tuberculous granuloma formation within cerebrum is the most common form of parenchymal tuberculosis. It is more frequently encountered in adolescents and adults. CECT brain can pickup tuberculous meningitis findings in appropriate clinical setting without the need for MRI. Pathophysiology Rupture of initial subependymal or subpial tubercule focus into subarachnoid space (after earlier haematogenous dissemination)into CSF - thick gelatinous exudate settles at base of brain along cisterns +sylvian fissure + along traversing vessels. Complications Communicating hydrocephalus due to blockage of basal cisterns by inflammatory exudate. Obstructive hydrocephalus - mass effect effect of tuberculoma causing obstruction of CSF flow. Ischaemic infarction in basal ganglia and internal capsule to vasospasm of penetrating vessels. Cranial neuropathy - extension of cisternal inflammation along traversing cranial nerves. Imaging features CT - iso or hypoattenuating meninges relative to basal cisterns and often homogenous contrast enhancement of meninges. MRI- Normal at unenhanced images at early stage. Distension of subarachnoid spaces. MRI - abnormal meningeal enhancement on gadolinium enhanced T1WI . abnormal enhancement of choroid plexus + ependymal lining. Non-caseating granuloma T1: iso- to- hypointense T2: hyperintense T1 C+ (Gd): homogeneous enhancement. Caseating granuloma T1: iso- to- hypointense with hyperintense rim T2:hypointense representing gliosis and abundant monocyte infiltration surrounded by vasogenic edema T1 C+ (Gd): homogeneous or ring-enhancement MR spectroscopy lipid-lactate peaks are usually elevated (86%)Caseating granuloma with central liquefaction T1: iso- to- hypointense with hyperintense rim T2:hypointense rim with central hyperintensity surrounded by vasogenic edema T1 C+ (Gd): ring enhancement Calcified granuloma T1: iso- to- hypointense T2: hypointense T1 C+ (Gd): no enhancement
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!