Tubercular Meningitis (TBM)
TBM is the most severe form of childhood tuberculosis, resulting from the hematogenous spread of Mycobacterium tuberculosis. It typically presents with a subacute or chronic clinical course.
1. Clinical Stages (British Medical Research Council)
| Stage | Clinical Features |
|---|---|
| Stage I | Non-specific (fever, malaise, headache); alert and oriented; no neurological deficit. |
| Stage II | Signs of meningeal irritation, cranial nerve palsies, altered sensorium, but still rousable. |
| Stage III | Coma, seizures, hemiplegia, or decerebrate posturing; life-threatening. |
2. Diagnosis & Investigations
- CSF Findings: Typical profile includes elevated protein (high), decreased glucose (low), and lymphocytic pleocytosis.
- Neuroimaging: CT/MRI may show basal meningeal enhancement, hydrocephalus, or tuberculomas.
- Confirmatory: GeneXpert (CBNAAT) on CSF is the investigation of choice for rapid diagnosis.
NEET PG Hint: Cranial nerve involvement—specifically CN VI (abducens) and CN III (oculomotor)—is a classic finding due to basal inflammation. Always remember that corticosteroids (dexamethasone or prednisolone) are a crucial adjunctive treatment to reduce mortality and neurological sequelae in TBM.