Tuberculous Meningitis With Hydrocephalus and Hyponatremia
A 34-year-old man from Baghdad presents with 3 weeks of fever, headache, night sweats, and 10 kg weight loss, followed by confusion and vomiting for 3 days. He has no HIV, no prior TB, and a BCG scar. Temperature is 38.4°C; he has neck stiffness, right abducens palsy, and drowsiness with GCS 13. Chest radiograph shows miliary opacities. CSF shows opening pressure 28 cmH2O, 120 white cells/µL (90% lymphocytes), protein 210 mg/dL, and glucose 32 mg/dL with serum glucose 110 mg/dL. MRI shows basal meningeal enhancement and communicating hydrocephalus. Serum sodium is 118 mmol/L; he is clinically euvolemic with no edema. The laboratory takes 3 weeks for culture; GeneXpert is available but the result is pending.
1. What immediate treatment would you start, and when would you use corticosteroids?
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Start empiric therapy now: the subacute fever, basal meningeal enhancement, hydrocephalus, miliary chest film, lymphocytic CSF, high protein, and low glucose strongly suggest tuberculous meningitis. Do not wait for culture. Begin isoniazid 5 mg/kg with pyridoxine 25 mg daily, rifampicin 10 mg/kg, pyrazinamide 25 mg/kg, and ethambutol 15 mg/kg, with dose adjustment for renal and liver function. Add dexamethasone 0.3-0.4 mg/kg/day, usually started before or with the first anti-TB doses, then tapered over 6-8 weeks. Steroids reduce mortality and neurologic sequelae in TB meningitis; HIV status would not change the indication but would change ART timing and interactions.
Reasoning: GeneXpert is pending but has imperfect sensitivity; compatible CSF and imaging justify empiric treatment. Check liver enzymes, baseline vision and color discrimination for ethambutol, and drug interactions with rifampicin.
2. How would you manage the hyponatremia and the hydrocephalus?
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Hyponatremia: sodium 118 mmol/L with euvolemia suggests SIADH, common in TB meningitis. Confirm volume status; if euvolemic, restrict fluids to about 800-1,000 mL/day and avoid rapid correction. If he is hypovolemic with high urine sodium, consider cerebral salt wasting and give isotonic saline. Correct no faster than 8-10 mmol/L in 24 hours to avoid osmotic demyelination. Monitor sodium every 6-12 hours initially.
Hydrocephalus: communicating hydrocephalus with drowsiness and vomiting is symptomatic. Urgent neurosurgical review for external ventricular drain if GCS declines or intracranial pressure is raised; a ventriculoperitoneal shunt may be needed if hydrocephalus persists. Acetazolamide is not a definitive treatment. Monitoring: repeat CT if headache or confusion worsens, and check for visual loss or cranial nerve deficits.
3. At 6 weeks he develops worsening headache, fever, and a larger ventricular size. How do you distinguish a paradoxical reaction from treatment failure, and what do you do?
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Paradoxical worsening at 6 weeks: worsening fever, headache, meningeal signs, or enlarging ventricles can be an immune reconstitution-like or paradoxical TB reaction. First exclude treatment failure: check adherence, drug absorption, resistance, and alternative infection; repeat CSF with culture and GeneXpert, and image the brain. If cultures are negative and the patient is otherwise improving, continue the same anti-TB regimen and consider a short course of corticosteroids; do not stop anti-TB drugs or add another antibiotic blindly. Ventricular enlargement with symptoms needs CSF diversion.
Key judgment: paradoxical reactions are diagnosed after excluding resistance and noncompliance, and treatment is continued.