Meningitis

Last updated: Thursday, 23, December, 2010
CausesAppropriate Tests

Cerebrospinal fluid examination - microscopy and culture; protein, glucose (compared with plasma glucose), India ink preparation, cryptococcal antigen if the CSF cell count is abnormal and/or if patient has HIV infection; cytology to identify eosinophils and malignant cells, if appropriate.

Blood culture.

Bacterial, especially

  • Neisseria meningitidis
  • Streptococcus pneumoniae
  • Mycobacterium tuberculosis

Mycobacteria testing - CSF.

See Mycobacterial infection
  • Listeria monocytogenes
See Listeriosis

In neonates  

Gastric aspirate, ear swabs - Gram stain and culture.

  • Group B streptococcus
  • Escherichia coli

Viral 

Often termed 'aseptic meningitis'.

Investigation is usually only of value in outbreaks or epidemics, to determine the specific virus responsible.

CSF, faeces, throat swab, nasopharyngeal aspirate - virus detection, culture as appropriate.

  • Enteroviruses
  • Herpes simplex virus type 2
See Herpes simplex infection

Fungal, especially

  • Cryptococcus neoformans 

See Cryptococcal infection

Protozoal 

CSF microscopy (including  phase contrast for motile trophozoites).

  • Naegleria fowleri

Helminthic 

CSF microscopy (including cytology for eosinophils).

  • Angiostrongylus sp

Malignancy 

CSF microscopy (including cytology).

  • Disseminated carcinoma