Community-acquired Bacterial Meningitis

Question 1

What is the pathogenesis of CA-bacterial meningitis?

Answer 1

1. pt is predisposed to factors and colonisation by bacteria that causes meningitis
2. bacteria gain entry into the body via
   - invasion of mucosal surface
   - para-meningeal focus
   - head trauma
   - anatomical defects in the meninges
   - neurosurgical procedures
3. in a susceptible host, bacteria enters the CNS

Question 2

What are the risk factors for bacterial meningitis?

Answer 2

• head trauma
• CNS shunts
• neurosurgical procedure
• CSF fistulas or leaks
• immunosuppression
• splenectomised pts
• congenital defects
• local infections (sinusitis, otitis media, pharyngitis)

Question 3

What are the classic triad of symptoms for bacterial meningitis?

Answer 3

Headache, neck rigidity, back ache

Question 4

What are the physical signs of bacterial meningitis?

Answer 4

• kernig sign (back pain when raise leg)
• brudzinski sign (reflex leg kick when head is lifted)
• bulging fontane (infants)

Question 5

What are the symptoms of bacterial meningitis?

Answer 5

altered mental status (irritability), photophobia, nausea, vomiting, anorexia
infants: poor feeding habits
n. meningitidis: petechiae or purpura

Question 6

What is the expected of the opening pressure of lumbar puncture in pt with bacterial meningitis?

Answer 6

Elevated opening pressure

Question 7

Differentiate the glucose levels of CSF in normal, bacterial, and viral meningitis.

Answer 7

normal: 2.6-4.5 mmol/L
bact: very low
viral: normal / slightly low

Question 8

Differentiate the protein levels of CSF in normal, bacterial, and viral meningitis.

Answer 8

normal: < 0.4 g/L
bact: raised, > 1.5 g/L
viral: normal to slightly raised

Question 9

Differentiate the WBC levels of CSF in normal, bacterial, and viral meningitis.

Answer 9

normal: < 5 cells/mm3
bact: raised, > 100 cells/mm3, mostly neutrophils
viral: raised, 5 - 1000 cells/mm3, mostly lymphocytes

Question 10

What are the pathogens to be considered in empiric treatment of bacterial meningitis in neonates (<1mo)?

Answer 10

s. agalactiae, listeria, e. coli

Question 11

What are the recommended regimens for empiric treatment of bacterial meningitis in neonates (<1mo)?

Answer 11

ceftriaxone + ampicillin (covers listeria)

Question 12

What are the pathogens to be considered in empiric treatment of bacterial meningitis in infants (1-23mo)?

Answer 12

s. pneumoniae, s. agalactiae, e. coli, n. meningitidis

Question 13

What are the recommended regimens for empiric treatment of bacterial meningitis in infants (1-23mo)?

Answer 13

ceftriaxone + vancomycin (cover ceftriaxone resistant s. pneumo)

Question 14

What are the pathogens to be considered in empiric treatment of bacterial meningitis in children and adults (2-50yrs)?

Answer 14

s. pneumoniae, s. agalactiae

Question 15

What are the recommended regimens for empiric treatment of bacterial meningitis in children and adults (2-50yrs)?

Answer 15

ceftriaxone + vancomycin

Question 16

What are the pathogens to be considered in empiric treatment of bacterial meningitis in older adults (>50yrs)?

Answer 16

s. pneumo, listeria, aerobic gram neg (e. coli, klebsiella), n. meningitidis

Question 17

What are the recommended regimens for empiric treatment of bacterial meningitis in older adults (>50yrs)?

Answer 17

ceftriaxone + vancomycin + ampicillin

Question 18

What is the recommended regimen (inc. duration) for culture-directed treatment of bacterial meningitis caused by s. pneumoniae?

Answer 18

penicillin susceptible: pen G or ampicillin
penicillin resistant: ceftriaxone
ceftriaxone resistant / pen allergy: vancomycin + rifampicin
duration: 10-14d

Question 19

What is the recommended regimen (inc. duration) for culture-directed treatment of bacterial meningitis caused by s. agalactiae?

Answer 19

penicillin G / ampicillin
mild penicillin allergy: ceftriaxone
duration: 14 - 21d

Question 20

What is the recommended regimen (inc. duration) for culture-directed treatment of bacterial meningitis caused by listeria?

Answer 20

penicillin G / ampicillin
pen allergy: bactrim, meropenem
duration: >= 21d

Question 21

What is the recommended regimen (inc. duration) for culture-directed treatment of bacterial meningitis caused by n. meningitidis?

Answer 21

penicillin G / ampicillin
pen allergy: ceftriaxone
duration: 5-7d

Question 22

For which age group is adjunctive corticosteroids recommended?

Answer 22

all pt > 6w

Question 23

What is the adult dosing regimen of adjunctive corticosteroids?

Answer 23

dexamethasone 10mg Q6H, up to 4 days
administer 10-20 min before / at the same time as first abx dose

Question 24

What are the benefits of adjunctive corticosteroids?

Answer 24

decreased neurological sequelae and hearing loss in h. influenzae and s. pneumoniae bacterial meningitis
decrease mortality in s. pneumoniae bacterial meningitis

Question 25

What are the risks of adjunctive corticosteroids?

Answer 25

decreased abx penetration
S/E: hypertension, hyperglycemia, mental status changes

Question 26

When should adjunctive corticosteroids be discontinued?

Answer 26

when pathogen causing meningitis is not s. pneumoniae / h. influenzae

Question 27

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)?

Answer 27

Rifampicin
Adults: 600mg Q12H, 4 doses
Children: 10 mg/kg Q12H, 4 doses
Infants: 5 mg/kg Q12H, 4 doses

Question 28

What are the other options for chemoprophylaxis of close contacts of meningococcal meningitis?

Answer 28

PO Ciprofloxacin 500mg single dose (adults only)
IM ceftriaxone 125 - 250mg single dose