Synonyms:
Mycobacterium tuberculosis meningitis, TB meningitis, tuberculoma, tuberculous meningovasculitis
Diagnosis:
Clinical features plus confirmatory CSF analysis or TB studies
Findings in Investigations:
- Findings remain after 10 days treatment
- White cell count: moderately high,
- Usually <500/microL, (100-300/mm3)
- Mainly lymphocytes
- Protein: High, >0.8g/L
- Glucose: Low ,<2.2 mmol/l
- Or atypically:
- Neutrophilia if early, normal protein, normal glucose
- Eosinophilia may occur
- Acid fast stain positive in 20%
- Culture is positive in 80%
- CSF PCR: for TB
MRI:
- Tuberculomas: gadolinium enhancement, nodular
- Infarctions in vasculitis
MRA:
- In vasculitis diffuse narrowing of the arteries. However, affected blood vessels are typically small and may not be abnormal on MRA
Angiogram/angiography:
- Proximal carotid artery & basilar artery stenosis: vasculitis of “basilar meningitis”
- May be normal
Pathology/biopsy:
Gross:
- Grey pus in the subarachnoid space, usually basal. Tuberculoma= round/oval mass with necrotic creamy centre.
Microscopic:
- Granuloma. Caseating necrosis, Langhan multinucleated giant cells, histiocytes, lymphocytes, plasmacytes. Surrounding gliosis in tuberculoma.
- Obliterative endarteritis= thickened intima by collagen. Fibrinoid necrosis & thrombosis of meningeal vessels.
- Ziehl-Neelsen stain: Acid fast (red) bacilli.
Treatment options:
Treat early, on clinical suspicion before confirmation by diagnostic tests
TB chemotherapy:
- Look up the updated regimen. Here are examples
- WHO regimen:
- 2 months P.O.: isoniazid +rifampin +pyrazinamide +ethambutol
- +4 months P.O. continuation: isoniazid +rifampin
- Infectious Diseases Society of America (IDSA) regimen:
- 2 months P.O.: isoniazid +rifampin +pyrazinamide +ethambutol
- 9-12 months continuation: isoniazid +rifampin
- Immunomodulation i.e. corticosteroids, NB. rifampin increased the dose needed
Hydrocephalus:
- Non-communicating:
- Immediate ventriculoperiotoneal shunt or external ventricular drain
- Communicating:
- Consider medications: frusemide +acetazolamide
- Consider ventriculoperitoneal shunt