Makindo Medical Notes

🧠 Tuberculosis can spread to the central nervous system, forming a Rich focus that may rupture into brain tissue. This can cause meningitis, tuberculomas, vasculitis, and hydrocephalus. Early recognition is critical for survival and prevention of long-term disability.

📖 About

• Presentation is often insidious, with subtle early features.
• Diagnosis is challenging but essential to prevent severe complications such as stroke or coma.

🧬 Tuberculous Involvement of the CNS

• TB Meningitis: Basal meningeal inflammation with high risk of hydrocephalus and cranial nerve palsies.
• Tuberculomas: Space-occupying granulomas causing focal neurology or seizures.
• Spinal Arachnoiditis: Pain, progressive weakness, and sometimes paralysis.
• TB Arteritis: Vasculitis leading to ischaemic strokes.
• Hydrocephalus: From impaired CSF resorption or blocked aqueduct.
• Cranial Nerve Involvement: Especially VI (abducens palsy) due to basal exudates.

⚠️ Aetiology & Risk Factors

• Recent TB exposure.
• HIV/AIDS or other immunosuppression.
• Alcoholism and malnutrition.

📊 Stages

• Stage I: Alert, rational, no focal neurology or hydrocephalus.
• Stage II: Confusion, with focal neurological signs.
• Stage III: Coma, hemiparesis/paraplegia, seizures, delirium.

🩺 Clinical Features

• Symptoms: Subacute fever, headache, malaise for 2–3 weeks.
• Signs: Meningism, vomiting, altered mental status, seizures.
• Cranial Nerve Palsies: Most often III & VI.
• Pathophysiology: Basal meningitis, optic chiasm involvement, vasculitis → thrombosis & infarcts.
• Hydrocephalus: From protein-rich CSF blocking resorption.
• Systemic: Lymphadenopathy, splenomegaly in some cases.

🔬 Investigations

• Bloods: FBC, U&E, LFTs, CRP/ESR (often raised).
• Mantoux Test: Positive in ~50%, not definitive.
• CSF: High protein (1–5 g/L), low glucose, lymphocytic pleocytosis. AFB smear often negative. Culture slow (up to 6 weeks). PCR can expedite diagnosis.
• Imaging:
  • CT: May be normal early. Later: basal enhancement, hydrocephalus, or tuberculomas.
  • MRI: Best for showing tuberculomas and basal exudates.
• HIV Test: Mandatory, given the strong association.

💊 Management

• Anti-TB Therapy:
  • 2 months: Isoniazid, Rifampicin, Pyrazinamide, Ethambutol.
  • Continuation: Isoniazid + Rifampicin for 7–10 months.
• Steroids: Dexamethasone or Prednisolone for raised ICP, hydrocephalus, or focal deficits. Taper over 4–8 weeks.
• Hydrocephalus: Ventriculoperitoneal shunt if severe.
• HIV Co-infection: Start HAART carefully (watch for IRIS).
• Supportive Care: Anticonvulsants if seizures, nutritional support, and monitoring for complications.

📌 Key Clinical Pearls

• Think of TB in subacute meningitis with cranial nerve palsies or basal exudates.
• Always test for HIV in suspected CNS TB.
• Start treatment early — waiting for culture confirmation can be fatal.
• Steroids improve survival and reduce neurological sequelae.