MRI Intracranial Tuberculosis
Intracranial tuberculosis is a serious, life-threatening infection of the brain caused by Mycobacterium tuberculosis, the bacteria responsible for tuberculosis (TB). It primarily affects the brain’s meninges, which are the protective layers covering the brain and spinal cord, but can also affect other parts of the central nervous system. Intracranial TB is a form of extrapulmonary tuberculosis, meaning it occurs outside of the lungs. The primary forms of intracranial TB include:
Tuberculous meningitis (TBM): It is the most common form of CNS tuberculosis and involves inflammation of the meninges, the layers that cover the brain and spinal cord.
Tuberculoma: This is a localized form of CNS tuberculosis, presenting as a granuloma or a mass in the brain or spinal cord.
Tuberculous abscess: This is a less common form, where there’s a collection of pus in the brain or spinal cord due to TB.
Tuberculous encephalopathy: A rare form with diffuse brain involvement without any evident meningitis or mass.
Symptoms of Intracranial Tuberculosis:
The symptoms of intracranial TB largely depend on the form and location of the disease, but they can include:
For Tuberculous meningitis:
- Gradual onset of symptoms
- Neck stiffness
- Altered consciousness
- Cranial nerve palsies
For Tuberculoma and Tuberculous abscess:
- Focal neurological symptoms, depending on the location (like weakness in one part of the body or problems with speech)
For Tuberculous encephalopathy:
- Rapidly progressing altered mental status
- Neurological deficits without other apparent causes.
A combination of clinical history, examination, and investigations like lumbar puncture, cerebrospinal fluid (CSF) analysis, imaging studies (like MRI and CT scan), and microbiological tests are used.
Antitubercular therapy (ATT): The cornerstone of treatment involves a combination of antitubercular drugs like isoniazid, rifampin, pyrazinamide, and ethambutol for an initial period, followed by continuation phase with isoniazid and rifampin. The exact duration and choice of drugs might vary based on the severity and the specific presentation, but treatment usually lasts for at least 12 months.
Corticosteroids: Especially for tuberculous meningitis, the use of adjunctive corticosteroids (like dexamethasone) has been shown to improve outcomes, especially in terms of reducing neurological complications.
Surgical intervention: In cases of large tuberculomas, abscesses, or hydrocephalus (increased fluid pressure in the brain), surgical procedures might be necessary.
Management of complications: Seizures, hydrocephalus, and other complications should be managed as they arise.
MRI appearance of Intracranial Tuberculosis (TB)
Intracranial Tuberculosis (TB) manifests differently in MRI sequences depending on its form and stage, such as Tuberculous Meningitis, Tuberculoma, or Abscess.
In general, tuberculomas appear hypo- or isointense on T1-weighted images. Lesions may be multiple or solitary. The edema surrounding the lesion will appear hypointense.
Tuberculomas can appear hypointense or iso-intense on T2-weighted images, often with a surrounding hypointense rim due to fibrosis. The edema surrounding the lesion will appear hyperintense.
FLAIR (Fluid-Attenuated Inversion Recovery):
Lesions typically appear hypointense or iso-intense on FLAIR images, aiding in the differentiation of lesions from the surrounding hyperintense edema.
DWI (Diffusion-Weighted Imaging):
Active tuberculomas and abscesses may restrict diffusion and appear hyperintense on DWI.
T1 Post-Contrast Images:
Enhancement patterns on post-contrast T1 images can be variable, ranging from ring enhancement, nodular enhancement to homogenous enhancement, especially in the case of tuberculomas and abscesses. Meningeal enhancement can be seen in tuberculous meningitis.
T2 axial image shows Intracranial Tuberculosis (TB)
FLAIR axial image shows Intracranial Tuberculosis (TB)
TI coronal image shows Intracranial Tuberculosis (TB)
T2 sagittal image shows Intracranial Tuberculosis (TB)
DWI b1000 axial image shows Intracranial Tuberculosis (TB)
DWI b0 axial image shows Intracranial Tuberculosis (TB)
ADC axial image shows Intracranial Tuberculosis (TB)
T1 post contrast axial image shows Intracranial Tuberculosis (TB)
T1 post contrast coronal image shows Intracranial Tuberculosis (TB)
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