Bacterial Meningitis

Reviewed and revised 14 November 2015

OVERVIEW

  • Bacterial meningitis = pyogenic infection of the cerebral ventricles and subarachnoid space -> CSF
  • usually confined to meninges (although in neonates and adults with Listeria monocytogenes -> cerebritis, encephalitis and abscesses can form)
  • 3 routes:
    • vascular,
    • transdural or
    • trans-parenchymal

RISK FACTORS

  • CSF leak (e.g. base of skull fracture)
  • Head and neck surgery or prostheses (e.g. cochlear implants, VP shunt, ICP monitor, EVD, craniectomy)
  • extremes of age (e.g. pneumococcus and listeria)
  • head and neck infections (e.g. sinusitis, mastoiditis, otitis media)
  • comorbidities (e.g. liver and renal failure)
  • immunosuppression (e.g. functional asplenia, splenectomy, hypogammaglobulinemia, complement deficiency, steroids, diabetes mellitus)
  • malnutrition
  • low socioeconomic status and overcrowding
  • exposure to epidemic

CLINICAL FEATURES

History

  • malaise
  • fever
  • headache
  • vomiting
  • stiff neck
  • risk factors

Examination

  • normal -> altered LOC -> coma
  • meningism
  • head jolt accentuation test (lateral head rotation worsens headache = very sensitive)
  • other signs less useful (e.g. Brudzinski sign)
  • papilloedema (indicates raised ICP)
  • tense fontanelle in babies

INVESTIGATION

  • LP – ideally prior to antibiotics (chances of getting bug decrease dramatically, however need to give as early if new seizure, papilloedema, focal neurology), opening pressure, WCC’s, decreased glucose
  • CT Head first if:
    • new onset seizures
    • immunocompromised
    • GCS < 10
    • focal neurological signs in keeping with a space occupying lesion.
  • routine blood tests
  • blood cultures
  • enterovirus and HSV PCR
  • bacterial PCR (pneumococcus, meningococcus)
  • cryptococcal antigen an India Ink
  • neurosyphilis
  • mycobacterium culture or PCR
  • immunocompromised + gram positive rods = Listeria

MANAGEMENT

Empiric Treatment

  • antibiotics within 30 min of initial assessment
  • dexamethasone 0.15mg/kg Q6 hourly with or before the first dose of antibiotics
  • ceftriaxone (immunocompetent) or vancomycin + ciprofloxacin/moxifloxacin
  • ceftriaxone + benzylpenicillin (immunocompromised to cover Listeria)
  • add vancomycin if staph seen on gram stain or at risk (e.g. indigenous, permanent lines, recent hospitalisation, known to be colonised)

Directed Treatment

  • Neisseria meningitidis – benzylpenicillin OR ceftriaxone OR ciprofloxacin
  • Streptococcus pneumonia – MIC <0.125mg/L to penicillin -> benzylpenicillin, MIC = 0.125mg/L to penicillin -> ceftriaxone + vancomycin OR rifampicin OR moxifloxacin
  • Haemophilus influenzae – ceftriaxone OR cefotaxime OR amoxicillin OR ciprofloxacin
  • Listeria monocytogenes – penicillin OR amoxicillin OR co-trimoxazole
  • Streptococcus agalactiae – benzylpenicillin
  • Cryptococcus neoformans or gattii – amphotericin B + flucytosine then go to fluconazole once CSF clear

COMPLICATIONS

Intracranial

  • abscess
  • cerebritis
  • deafness
  • cognitive impairment
  • hydrocephalus

Extracranial

  • septic shock
  • adrenal insufficiency from infarction (Waterhouse–Friderichsen syndrome (WFS))
  • ARF
  • purpura fulminans
  • necrotising vasculitis -> skin necrosis and digital gangrene

PUBLIC HEALTH CONSIDERATIONS

  • Neisseria meningitidis
    • requires droplet precautions
    • post-exposure prophylaxis needed for close contacts if <24h treatment with appropriate antibiotics
      • ciprofloxacin 500 mg (child younger than 5 years: 30 mg/kg up to 125 mg; child 5 to 12 years: 250 mg) orally, as a single dose, OR
      • ceftriaxone 250 mg (child 1 month or older: 125 mg) IM, as a single dose (preferred option for pregnant women), OR
      • rifampicin 600 mg (neonate: 5 mg/kg; child: 10 mg/kg up to 600 mg) orally, 12-hourly for 2 days
        (NB. interacts significantly with many drugs (eg with the oral contraceptive pill) and is contraindicated in pregnancy and severe liver disease)

ROLE OF STEROIDS

Multiple studies and meta-analyses conflicting results with mortality and neurological sequelae. Neurological sequelae seen in up to 50% of survivors of community-acquired meningitis.

Cochrane review 2013: Overall –

  • Trend to reduction in mortality
  • Reduced rate of hearing loss
  • Reduced rate of short-term neurological sequelae 
subgroup analyses –
  • Reduced hearing loss in children with h influenza only
  • Favourable effect on mortality with s pneumonia only
  • No effect in low income countries, except possibly for tb meningitis

Approach to use of adjunctive steroids

  • Adults in developed world – suspected or proven pneumococcus. Therefore commence steroids in all and discontinue if proven to not be pneumococcus.
  • Children – suspected or proven H influenza, although many recommendations do include steroids for suspected pneumococcal or meningococcal as well. 
Given prior to, or with first dose of antibiotics. Continued for 4 days.
  • Potential side-effects of steroids
 – Concern that steroids may reduce antibiotic penetration into CSF (esp Vancomycin) – controversial. Generic SEs – e.g. hyperglycaemia, GI bleed, immunosuppression etc.

References and Links

Journal articles

  • Dando SJ, Mackay-Sim A, Norton R. Pathogens penetrating the central nervous system: infection pathways and the cellular and molecular mechanisms of invasion. Clinical microbiology reviews. 27(4):691-726. 2014. [pubmed]
  • Honda H, Warren DK. Central nervous system infections: meningitis and brain abscess. Infectious disease clinics of North America. 23(3):609-23. 2009. [pubmed]
  • Prasad K, Sahu JK. Cerebrospinal fluid lactate: is it a reliable and valid marker to distinguish between acute bacterial meningitis and aseptic meningitis? Critical care (London, England). 15(1):104. 2011. [pubmed]
  • Radetsky M. Fulminant bacterial meningitis. The Pediatric infectious disease journal. 33(2):204-7. 2014. [pubmed]
  • van de Beek D, de Gans J, McIntyre P, Prasad K. Corticosteroids for acute bacterial meningitis. The Cochrane database of systematic reviews. 2007. [pubmed]
  • van de Beek D, de Gans J, Tunkel AR, Wijdicks EF. Community-acquired bacterial meningitis in adults. The New England journal of medicine. 354(1):44-53. 2006. [pubmed]

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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