Community-onset Bacterial Meningitis

These materials are intended for general clinical education and guidance. They are not a substitute for a clinician’s knowledge, skill or judgment in treating patients.

Note: Urgent Infectious Disease consultation strongly advised.

Background

Meningitis is inflammation of the meninges and is a medical emergency.

Initial assessment

• Empiric antibiotic therapy should begin as soon as possible in suspected cases; time to antibiotics should not exceed one hour.
• When feasible, perform a lumbar puncture and send for cell count, glucose, protein, culture and BioFire EM multiplex PCR.
• A head CT before lumbar puncture (LP) is recommended if any of the following are present:
  • focal neurologic deficits
  • new-onset seizures
  • severely altered mental status (Glasgow Coma Scale score < 10)
  • A severely immunocompromised state
• In patients without these findings, head CT before LP is not recommended and is associated with poorer outcomes.
• If LP is delayed (for example, for a head CT), start empiric therapy immediately after obtaining blood cultures, even if the diagnosis has not been confirmed.

Common pathogens

• S. pneumoniae
• N. meningitidis
• L. monocytogenes
• H. influenzae

Empiric therapy (first-line)

No known allergies:

• Ceftriaxone 2 g IV q12h

AND

• Vancomycin 25 mg/kg IV (loading dose once), then 15 mg/kg IV q12h

AND

• Dexamethasone 10 mg IV q6h for four days* (start immediately before, with, or up to four hours after the first antibiotic dose)

Consider also:

• Ampicillin 2 g IV q6h (if age ≥ 50, pregnant or immunocompromised)
• Acyclovir 10 mg/kg IV q8h if clinical features of encephalitis are present

Alternative regimens for allergy to first-line regimen

Penicillin or amoxicillin allergy (unknown reaction, intolerance and/or type 1 hypersensitivity):

• Ceftriaxone 2 g IV q12h

AND

• Vancomycin 25 mg/kg IV (loading dose once), then 15 mg/kg IV q12h

AND

• Dexamethasone 10 mg IV q6h for four days* (start immediately before, with or up to four hours after the first dose of antibiotics)

Consider also:

• TMP-SMX 5 mg/kg (based on TMP component) IV q6h in place of ampicillin (if age ≥ 50, pregnant or immunocompromised)
• Acyclovir 10 mg/kg IV q8h if clinical features of encephalitis are present

Severe systemic or cutaneous reaction (unable to use any beta-lactem):

• Moxifloxacin 400 mg IV q24h (in place of ceftriaxone)

AND

• Vancomycin 25 mg/kg IV (loading dose once), then 15 mg/kg IV q12h

AND

• Dexamethasone 10 mg IV q6h for four days* (start immediately before, with or up to four hours after the first dose of antibiotics)

Consider also:

• TMP-SMX 5 mg/kg (based on TMP component) IV q6h in place of ampicillin (if age ≥ 50, pregnant or immunocompromised)
• Acyclovir 10 mg/kg IV q8h if clinical features of encephalitis are present

Targeted therapy for common pathogens

Clinical pearls

Adjunctive dexamethasone:

• Associated with decreased mortality and neurologic sequelae in S. pneumoniae and H. influenzae → continue dexamethasone for four days
• Shows no proven benefit in N. meningitidis and increased mortality in L. monocytogenes → discontinue upon microbiological diagnosis

Infection control:

• Chemoprophylaxis for close contacts and droplet isolation for the first 24 hours of therapy are indicated only for N. meningitidis and H. influenzae