Chronic meningitis

Background

Fungal infections
- Cryptococcus
- Coccidioides
- Histoplasma
- Candida
- Sporothrix (rare)
- Blastomyces (rare)
- Other rare molds: Scedosporium, Aspergillus, Cladophialophora, and other dematiaceous molds
Bacterial infections
- Mycobacterium tuberculosis
- Treponema pallidum
- Borrelia burgdorferi
- Tropheryma whipplei
- Actinomyces (parameningeal, rare)
- Nocardia (with brain abscess)
- Brucella (rare)
Viral infections
- Echovirus (meningoencephalitis)
Parasitic infections
Other causes
- Post-neurosurgical causes: infected CSF shunt, infected prosthetic material
- Tumours: diffuse gliomatosis, metastatic meningeal malignancies including lymphomatous meningitis
- Others: sarcoidosis, Vogt-Koyanagi-Harada syndrome, Behçet syndrome, IgG4-related hypertrophic pachymeningitis

CSF tests:
- Glucose, protein, cell count and differential (including eosinophils)
- India ink on centrifuged sediment
- Fungal culture of 3-5 mL of CSF
- Cytopathology for malignant cells, including PCR or flow cytometry for monoclonal B cells
- Periodic acid-Schiff stain for Whipple disease
- VDRL test
- Cryptococcal antigen
- Histoplasma antigen
- Aspergillus galactomannan antigen
- Coccidioides antibody by complement fixation or immunodiffusion
- PCR for tuberculosis, Whipple disease, enterovirus, and lymphoma
- Culture for enterovirus and Acanthamoeba
Blood tests
- RPR or other routine syphilis screening
- Serology for Coccidioides, Histoplasma, Toxoplasma, and Brucella antibodies
- Serology for Histoplasma antigen (may be from blood or urine)
Brain biopsy has low diagnostic yield in chronic meningitis