Send Feedback

Print

Mobile

 Back

CDHB

Acute Bacterial Meningitis

Clinical Features

Fever, headache, photophobia, neck stiffness and impaired sensorium. The latter may be the only sign in the elderly. Typically short duration of symptoms (<24 hrs) prior to admission.

Causes

• S. pneumoniae, N. meningitidis, H. influenzae (usually paediatric - rare since HIB vaccine). Listeria monocytogenes (immunosuppressed, elderly or pregnant).
• Leptospirosis, Gram negative bacilli (rare overall but important causes in neonates, the elderly, immunosuppressed, and post trauma), syphilis. Staphylococci (post-neurosurgical).
• Cryptococcus neoformans.

Pathogenesis

• Cryptogenic.
• Septicaemic illness.
• Secondary to head or neck sepsis e.g., ear, dental, sinus.
• Following head injury, CSF leak or sinus fracture.
• Complement deficiency, especially C7 and 8.
• Immunosuppression including steroids, malignancy and HIV.
• CSF shunts.

Investigations

• Blood cultures - 2 sets before antibiotics given.
• Lumbar puncture. Caution - refer to Management and lumbar puncture technique.
• Obtain a CT/MRI head scan urgently before doing a lumbar puncture if:
  • There is clinical evidence of raised intracranial pressure/space occupying lesion (raised BP, decreased pulse, decreased level of consciousness), seizures, papilloedema, focal neurological signs, or sinus or ear infections, or
  • The patient is immunosuppressed, or
  • The symptoms have lasted more than 5 days.

    Note: If a lumbar puncture cannot be done immediately make sure that appropriate antibiotics are given at once. If antibiotics were given before the patient reached hospital make sure the correct dose and type of antibiotic was used and if necessary give supplementary doses.

• Lumbar puncture: collect 2 mL of CSF into each of three numbered sterile vials. Send to Microbiology. Request cell counts, glucose, protein, culture and Gram stain. Antigen detection tests and viral culture should be done if WBC count is >5 x 10⁶ cells/L of CSF. PCR testing for N. meningitidis, H. simplex, TB and enterovirus is available, but not routine.
• CBC + diff.
• Na, K, glucose, creatinine, AST, GGT, ALP, bili.
• Chest and sinus X-rays (not all cases).
• Coagulation profile.
• Special tests needed for cryptococcus, TB, viruses, amoeba - consult Microbiologists, if indicated.

Usual CSF Patterns in Meningitis

Initial Management

• When to lumbar puncture:
  • If no contraindications to lumbar puncture, perform this as soon as possible and prior to administering antimicrobial therapy.
  • If patient is stable and needs a CT brain, do not administer antibiotics but arrange an urgent CT scan of brain.
  • If patient unstable or deteriorating rapidly, then administer antibiotics prior to CT scan. Give dexamethasone and antibiotics. Lumbar puncture promptly following CT scan if no radiological or clinical contraindications.
• Start dexamethasone 10 mg q6h IV.
• When to start antibiotics:
  • After dexamethasone has been given.
  • If patient unstable, reduced level of consciousness or unconscious, start antibiotics immediately.
  • If patient stable, delay antibiotics until after LP has been performed.
  • If there will be a delay while waiting for CT brain.
• Which antibiotics to start:
  • If between 15 and 60 years, and no evidence of immunosuppression, chronic sinus disease, or long term administration of antibiotics: give IV ceftriaxone 2 g q12h.
  • If over 60 years or evidence of immunosuppression, alcoholism or diabetes: give IV ceftriaxone 2 g q12h and IV amoxicillin 2 g q4h - q6h to cover potential Listeria monocytogenes infection.
  • If sinus disease or recent long term administration of antibiotics: give IV ceftriaxone 2 g q12h and IV vancomycin 30-40 mg/kg/day in 2 divided doses (see the Antimicrobial Guidelines in the Pink Book for dosing).
• Early treatment modification:
  • If CSF suggests viral meningitis or shows N. meningitidis, stop steroids.
  • If CSF shows N. meningitidis, use either IV benzylpenicillin or IV ceftriaxone.
  • If evidence of pneumococci in CSF either on Gram strain or by antigen test, continue treatment with both IV ceftriaxone 2 g q12h and vancomycin as per Pink Book dosing guidelines until sensitivities known and continue IV dexamethasone 10 mg q6h for 4 days. If there is renal impairment, monitor vancomycin levels and seek advice. See also the Pink Book. Consult Infectious Diseases Service.
• If in doubt, phone the Infectious Diseases Physician on call.

Subsequent Management

The spread of pneumococcal strains which are resistant to penicillin and ceftriaxone has led to changes in recommendations for empiric treatment of meningitis in some centres. Currently penicillin resistant pneumococci are rare <10% in New Zealand. The recommendations given here may need to change, depending on the local prevalence of these organisms.

• Proven or presumed pyogenic meningitis:
  • The following recommendations apply to all patients over 15 years. This includes previously well patients, and those with complicating pre-existing illness such as ear or sinus disease, immunosuppression, or recent pregnancy.
  • When cultures are available, modify the treatment according to the organisms isolated. Intravenous benzylpenicillin 2.4 g q4h is the preferred treatment if the organism, e.g., pneumococci, is sensitive.
  • If severely penicillin or cephalosporin allergic, chloramphenicol 80-100 mg/kg/day IV up to 4 g daily in 4 divided doses should be given. Check with ID Consultant first.
  • Meningococci must be cleared from the nasopharynx before the end of the treatment period. Give ciprofloxacin 500 mg as a single oral dose or rifampicin 600 mg BD PO for 2 days. This is not necessary if the patient has received ceftriaxone therapy.
  • Close household contacts of patients with meningococcal meningitis should be given ciprofloxacin 500 mg stat as prophylaxis as above as soon as diagnosis made. Throat swab not necessary. If pregnant give ceftriaxone 250 mg single dose IM or IV. Public Health Unit staff will trace contacts and arrange for further appropriate prophylactic antibiotics to be given.
  • Notify MOH if applicable.
  • Under 15 years seek paediatric advice.

Topic Code: 1453