Meningitis Flashcards
What is the pathogenesis of meningitis
Bact gain entry into body via
- Invasion of mucosal surface –> hematogenous spread to brain
- Penetrating head trauma
- Anatomic defects in meninges
- Prev neurosurgical procedures
Colonisation of bact in meninges of a susceptible host
Overgrowth –> meningitis
What is the general aetiology of meningitis?
Septic menigitis: Bact
Aseptic meningitis:
Viral
Other microorg: fungal, parasitic, mycobact, syphilis
Drugs (e.g. cotrimoxazole, ibuprofen - irritate meninges, inflamm)
Autoimmune diseases
What are the symptoms of meningitis?
Fever, chills, rigors
Alt mental status
Classic triad: Headache, Backache, Nuchal (neck) rigidity
NV
Anorexia
Poor feeding habits
Photophobia
Petechiae or purpura (Neisseria meningitidis)
What are the signs of meningitis?
WBC, CRP, procalcitonin
Kernig’s sign = hamstring extended, thigh perpendicular to trunk leads to severe back pain
Brudzinski sign = when head held up, natural reflex of flexion of hip and knee
Bulging fontane = CSF accum
Differentiate CSF in normal vs bact meningitis vs viral meningitis.
Glucose:
Normal - glucose:plasma > 0.66
Bact meningitis - glucose:plasma low <0.4
Viral meningitis - glucose:plasma normal to low
Proteins:
Normal - Low <0.4 g/L
Bact meningitis - Elevated >1.5g/L
Viral meningitis - Normal to mildly raised
Wbc:
Normal - <5 cells/mm^3
Bact meningitis - elevated, mostly neutrophils >100 cells/mm^3
Viral meningitis - elevated, mostly lymphocytes 5-1000 cells/mm^3
How do we diagnose meningitis?
Hx & physical exams
Blood cultures
Lumbar puncture: elevated opening P, CSF composition, gram stain & culture
Radiology
When do we do radiology for meningitis?
To evaluate for complications or disease progression, differential diagnosis.
If pt is unconscious or low alertness
Do prior to lumbar puncture where there is concern for brain shift
What are the bugs to cover for meningitis in neonates (<1mo)?
Group B streptococcus (S. aagalactiae)
E. coli
Listeria monocytogenes
What are the bugs to cover for meningitis in infants and children (1-23 mo)?
Group B streptococcus (S. agalactiae)
E. coli
S. pneumoniae
Neisseria meningitidis
What are the bugs to cover for children and adults (2-50y)?
S. pneumoniae, Neisseria meningitidis
What are the bugs to cover for elderly?
S. pneumoniae
Neisseria meningitidis
Listeria monocytogenes
Aerobic gram -ve
What is the recommended regimen for neonates (<1mo)?
IV ceftriaxone AND IV ampicillin (for listeria)
What is the recommended regimen for infants and children (1-23mo)?
IV ceftriaxone AND IV vancomycin
What is the recommended regimen for children and adults (2-50y)?
IV ceftriazone AND IV vancomycin
What is the recommended regimen for elderly?
IV ceftriaxone AND IV vancomycin AND IV ampicillin (for listeria)
What is the recommended regimen for culture directed Listeria monocytogenes?
IV ampicillin or penicillin
Penicillin allergy: IV cotrimoxazole, meropenem
What is the recommended regimen for culture directed S. pneumoniae?
Penicillin susceptible: IV Pen G or ampicillin
Penicillin resistant, cephalosporin susceptible: Ceftriaxone
Penicillin, cephalosporin resistant: IV vancomycin AND rifampicin
What is the recommended regimen for culture directed Neisseria meningitidis?
Penicillin susceptible: IV Penicillin G or ampicillin
Penicillin resistant or mild allergy: IV Ceftriaxone
What is the recommended regimen for culture directed Group B Streptococcus (S. agalactiae)?
Penicillin susceptible: IV Pen G or ampicillin
Penicillin resistant or mild allergy: IV Ceftriaxone
What is the recommendation for adjunctive corticosteroid therapy?
10 mg Q6H for up to 4d, 10-20min before first dose of abx.
Only for H. influenzae and S. pneumoniae meningitis
What are the benefits of adjunctive corticosteroid thera in H. influenzae and S. pneumoniae meningitis?
Less hearing loss & other neurologic sequelae
Decreased mortality (S. pneumoniae)
What are the concerns for adjunctive corticosteroid therapy in H. influenzae and S. pneumoniae meningitis?
May decrease abx penetration.
ADR: mental status changes, hyperglycemia, HTN
What is the recommendation for antibiotic chemoprophylaxis with respect to meningococcal meningitis?
Rifampicin
Adults: 600 mg Q12H, four doses
Children: 10 mg/kg Q12H, four doses
Infants: 5 mg/kg Q12H, four doses
Ciprofloxacin 500 mg once daily, one dose
Ceftriaxone 140-250 mg IM, one dose
What are the risk factors for meningitis?
Head trauma
Neurosurgery
CSF shunts
CSF fistula or leaks
Abnormalities in meninges (Congenital defects)
Drugs
Splenectomised pts
Immunosuppression
What is the duration of treatment for Listeria monocytogenes?
> =21d
What is the duration of treatment for Neisseria meningitidis?
5-7d
What is the duration of treatment for Group B Streptococcus (S. agalactiae)?
14-21d
What is the duration of treatment for S. pneumoniae?
10-14d
How do we de-escalate if there is -ve culture?
Treat with empiric abx for at least 14d. May be extended dep on condition of pt
