Bacterial Meningitis / Encephalitis


Samples required

  • CSF and blood cultures essential
  • Additional samples: - EDTA blood for bacterial PCR   - pink throat swab+stool samples for Enterovirus PCR.
  • If TB meningitis is suspected - minimum of 6ml of CSF required
First Line

Ceftriaxone 2g IV 12 hourly

Add Amoxicillin 2g IV 4 hourly to cover Listeria if older than 60 years, pregnant, immunosuppressed or alcohol excess

Penicillin Allergy

Meropenem 2g IV 8 hourly

(no additional Listeria cover needed as meropenem has activity)


If true immediate anaphylaxis reaction to penicillin :

Chloramphenicol 25mg/kg IV 6 hourly 

ADD Co-trimoxazole 1.44g IV 12 hourly to cover Listeria if > 60 years old, immunosuppressed or alcohol excess (For pregnant patients - contact microbiology for further advice)

  • 9.9mg dexamethasone IV 6 hourly should be started either shortly before or alongside antibiotics in suspected meningitis.
  • If antibiotics have already been started, the first dose of dexamethasone can still be given up to 12 hours after the first dose of antibiotics.
  • If pneumococcal meningitis is confirmed or thought most probable, continue dexamethasone for four days and then stop.
  • If another cause of meningitis is confirmed or thought probable, the dexamethasone should be stopped.

Duration depends on pathogen identified:

  • Meningococcal: 5-7 days
  • Pneumococcal: 10-21 days
  • H. influenzae type B:  10 days
  • Listeria: 21 days
  • No pathogen identified: 10 days (discuss with microbiology or ID consultant)