Treatment For A Suspected Case Of Tuberculous Meningitis

A 40-yr-old woman presents with progressive confusion and mild neck stiffness. She has
suffered from increasing headaches over the past 4-6 wks, and over the past wk she has begun
to suffer from worsening drowsiness and confusion, with neck stiffness. A CT scan showed basal
meningeal enhancement. A lumbar puncture showed an opening pressure of 200 mmH2O, a
turbid CSF with 500 leucocytes/ml (90% lymphocytes), a glucose concentration of 1 mmol/l and
negative results with Gram, Indian ink and Ziehl–Neelsen stains. CSF protein is elevated at
1.05g/l (<0.50).
What is the best Rx?
A. Rifampicin + INAH + pyrazinamide + Ethambutol
B. Ceftriaxone
C. Aciclovir
D. Corticosteroids
E. Liposomal amphotericin B


Answer:
A-- Rifampicin + INAH + pyrazinamide + Ethambutol

Discussion: Rifampicin + INAH (isonicotinic acid hydrazide) + pyrazinamide + ethambutol are used to treat tuberculous meningitis (TBM), which is the most likely Dx based on the subacute Hx, CT
findings and the modest lymphocytic lymphocytosis accompanied by severe hypoglycorrhacia.
A negative Ziehl–Neelsen stain is not unusual in such cases, except when large volumes of spun CSF are examined. Almost without exception, Pts with bacterial meningitis have a high neutrophil pleocytosis and a few days’ Hx at presentation. Apparently, the Pt had not been receiving antibiotics, which can modify the CSF in those with bacterial meningitis.

Viral meningitis is unlikely since in viral meningitis the sugar concentration would be normal or only
slightly reduced (except in Pts with mumps meningitis); the cell count would by lymphocytic but generally less than the cell count here.

There is no reason to suspect fungal meningitis as she has no immunocompromising conditions, although the CSF changes may be indistinguishable from TBM. However, cryptococcal meningitis occasionally presents in a normal host, but here the Indian-ink stain is usually positive.

There is no evidence that the Pt has idiopathic intracranial hypertension or collagen vascular disease, so steroids are not indicated and are contraindicated for the Rx of infectious meningitis alone.

Bacterial meningitis is treated with ceftriaxone, viral meningitis with aciclovir and fungal meningitis with liposomal amphotericin B.