Community-acquired Bacterial Meningitis Flashcards
What is the pathogenesis of CA-bacterial meningitis?
- pt is predisposed to factors and colonisation by bacteria that causes meningitis
- bacteria gain entry into the body via
- invasion of mucosal surface
- para-meningeal focus
- head trauma
- anatomical defects in the meninges
- neurosurgical procedures - in a susceptible host, bacteria enters the CNS
What are the risk factors for bacterial meningitis?
- head trauma
- CNS shunts
- neurosurgical procedure
- CSF fistulas or leaks
- immunosuppression
- splenectomised pts
- congenital defects
- local infections (sinusitis, otitis media, pharyngitis)
What are the classic triad of symptoms for bacterial meningitis?
Headache, neck rigidity, back ache
What are the physical signs of bacterial meningitis?
- kernig sign (back pain when raise leg)
- brudzinski sign (reflex leg kick when head is lifted)
- bulging fontane (infants)
What are the symptoms of bacterial meningitis?
altered mental status (irritability), photophobia, nausea, vomiting, anorexia
infants: poor feeding habits
n. meningitidis: petechiae or purpura
What is the expected of the opening pressure of lumbar puncture in pt with bacterial meningitis?
Elevated opening pressure
Differentiate the glucose levels of CSF in normal, bacterial, and viral meningitis.
normal: 2.6-4.5 mmol/L
bact: very low
viral: normal / slightly low
Differentiate the protein levels of CSF in normal, bacterial, and viral meningitis.
normal: < 0.4 g/L
bact: raised, > 1.5 g/L
viral: normal to slightly raised
Differentiate the WBC levels of CSF in normal, bacterial, and viral meningitis.
normal: < 5 cells/mm3
bact: raised, > 100 cells/mm3, mostly neutrophils
viral: raised, 5 - 1000 cells/mm3, mostly lymphocytes
What are the pathogens to be considered in empiric treatment of bacterial meningitis in neonates (<1mo)?
s. agalactiae, listeria, e. coli
What are the recommended regimens for empiric treatment of bacterial meningitis in neonates (<1mo)?
ceftriaxone + ampicillin (covers listeria)
What are the pathogens to be considered in empiric treatment of bacterial meningitis in infants (1-23mo)?
s. pneumoniae, s. agalactiae, e. coli, n. meningitidis
What are the recommended regimens for empiric treatment of bacterial meningitis in infants (1-23mo)?
ceftriaxone + vancomycin (cover ceftriaxone resistant s. pneumo)
What are the pathogens to be considered in empiric treatment of bacterial meningitis in children and adults (2-50yrs)?
s. pneumoniae, s. agalactiae
What are the recommended regimens for empiric treatment of bacterial meningitis in children and adults (2-50yrs)?
ceftriaxone + vancomycin
What are the pathogens to be considered in empiric treatment of bacterial meningitis in older adults (>50yrs)?
s. pneumo, listeria, aerobic gram neg (e. coli, klebsiella), n. meningitidis
What are the recommended regimens for empiric treatment of bacterial meningitis in older adults (>50yrs)?
ceftriaxone + vancomycin + ampicillin
What is the recommended regimen (inc. duration) for culture-directed treatment of bacterial meningitis caused by s. pneumoniae?
penicillin susceptible: pen G or ampicillin
penicillin resistant: ceftriaxone
ceftriaxone resistant / pen allergy: vancomycin + rifampicin
duration: 10-14d
What is the recommended regimen (inc. duration) for culture-directed treatment of bacterial meningitis caused by s. agalactiae?
penicillin G / ampicillin
mild penicillin allergy: ceftriaxone
duration: 14 - 21d
What is the recommended regimen (inc. duration) for culture-directed treatment of bacterial meningitis caused by listeria?
penicillin G / ampicillin
pen allergy: bactrim, meropenem
duration: >= 21d
What is the recommended regimen (inc. duration) for culture-directed treatment of bacterial meningitis caused by n. meningitidis?
penicillin G / ampicillin
pen allergy: ceftriaxone
duration: 5-7d
For which age group is adjunctive corticosteroids recommended?
all pt > 6w
What is the adult dosing regimen of adjunctive corticosteroids?
dexamethasone 10mg Q6H, up to 4 days
administer 10-20 min before / at the same time as first abx dose
What are the benefits of adjunctive corticosteroids?
decreased neurological sequelae and hearing loss in h. influenzae and s. pneumoniae bacterial meningitis
decrease mortality in s. pneumoniae bacterial meningitis
What are the risks of adjunctive corticosteroids?
decreased abx penetration
S/E: hypertension, hyperglycemia, mental status changes
When should adjunctive corticosteroids be discontinued?
when pathogen causing meningitis is not s. pneumoniae / h. influenzae
What is the drug of choice for chemoprophylaxis of close contacts of meningococcal meningitis for children and what is its dose for adults, children, and infants (<1mo)?
Rifampicin
Adults: 600mg Q12H, 4 doses
Children: 10 mg/kg Q12H, 4 doses
Infants: 5 mg/kg Q12H, 4 doses
What are the other options for chemoprophylaxis of close contacts of meningococcal meningitis?
PO Ciprofloxacin 500mg single dose (adults only)
IM ceftriaxone 125 - 250mg single dose
