meningitis (exam 1) Flashcards
meningitis is inflammation predominantly of the __ space, most commonly due to __
- subarachnoid space
- infection
meningitis: etiology can be
- viral (aseptic)
- bacterial
- fungal (less common)
__ meningitis is a medical emergency and must be distinguished from the more common __ meningitis
- bacterial
- viral
incidence of bacterial meningitis in the US has been __
declining
meningitis has an overall mortality of __%
15-25%
bacterial meningitis: 3 types of infection
- community acquired: etiologic organisms vary with age
- nosocomial: primarily a disease of neurosurgical pts
- recurrent: most common in pts with nosocomial meningitis with compromised meningeal integrity
bacterial meningitis: major causes of community acquired bacterial meningitis are
- S. pneumoniae (pneumococcal)
- N. meningitides (meningococcal)
- H. influenzae
- Listeria monocytognes
bacterial meningitis: major causes of healthcare associated bacterial meningitis are
- staphylococci
2. aerobic gram negative bacilli
pt population: infants <1 mo
likely pathogens, antimicrobial therapy:
- S. agalactiae
- L. monocytogenes
- E. coli
- gram negative bacilli
- Ampicillin plus Cefotaxime OR
- Amplicillin plus an aminoglycoside
pt population: children 1-23 mos
likely pathogens, antimicrobial therapy:
- S. pneumoniae
- N. meningitidis
- S. agalactiae
- H. influenzae
- E. coli
- Vancomycin (gram + coverage!) and ceftriaxone (3rd generation cephalosporin)
[dexamethoason - whenever S. pneumonia is a possibility]
[some experts would add rifampin if dexamethoasone given]
[add ampicillin if L. monocytogenes suspected]
pt population: children and adults 2-50 years
likely pathogens:
- N. meninditidis
- S. pneumoniae
- Vancomycin and ceftriaxone
[dexamethoason - whenever S. pneumonia is a possibility]
[some experts would add rifampin if dexamethoasone given]
[add ampicillin if L. monocytogenes suspected]
pt population: >50 yo
likely pathogens:
- S. pneumoniae
- N. meningitidis
- L. monocytogenes
- aerobic gram negative bacilli
- Vancomycin, ceftriaxone, and ampicillin
[dexamethoason - whenever S. pneumonia is a possibility]
[some experts would add rifampin if dexamethoasone given]
[add ampicillin if L. monocytogenes suspected]
pt population: pt with basilar skull fx or cochlear implant
likely pathogens:
- S. pneumoniae
- H. influenzae
- GABHS
- Vancomycin plus (ceftriaxone) 3rd generation cephalosporin
[dexamethoason - whenever S. pneumonia is a possibility]
[some experts would add rifampin if dexamethoasone given]
[add ampicillin if L. monocytogenes suspected]
pt population: pt with penetrating trauma or s/p neurosurgery
likely pathogens:
- S. aureus
- P. aeruginosa
- aerobic gram negative bacilli
- coagulase negative staphylococci
- Vancomycin plus cefepime OR
- Vancomycin plus ceftazidime OR
- Vancomycin plus meropenem
pt population: pt with CSF shunt
likely pathogens:
- coagulase negative staphyloccus
- S. aureus
- aerobic gram negative bacilli
- P. aeruginosa
- Propionibacterium acnes
- Vancomycin and cefepime
bacterial meningitis: __ organism depends on __ of entry and __ factors
- etiological
- route/site
- host
bacterial meningitis, 3 mechanisms of entry:
- colonization of __ with subsequent __ invasion followed by __ invasion
- invasion of the CNS following __ due to localized source/infection (GI; endocarditis)
- __ entry into the CNS from __ infection (otitis media, mastoiditis, sinusitis), __, __, or medical __
- nasopharynx
- bloodstream
- CNS
-bacteremia
- direct
- contiguous
- trauma
- neurosurgery
- devices (shunt)
bacterial meningitis host factors that can predispose to meningitis
- asplenia
- complement deficiency
- glucocorticoid excess
- diabetes mellitus
- alcoholism
- hypogammaglobulinemia (not producing immunoglobulins)
- HIV
- recent infection (respiratory, ear)
- recent exposure to someone with meningitis
- IVDA (IV drug user)
- recent head trauma
- otorrhea or rhinorrhea
- recent travel to area with endemic meningococcal disease (Africa)
bacterial meningitis: classic triad of symptoms are
- fever: often high (>38C or 100.4F)
- nuchal rigidity = pathognomonic sign of meningitis
- change in mental status (delirium, confusion; test by mini-mental; level of consciousness)
bacterial meningitis clinical presentation
- fever: often high (>38C or 100.4F)
- nuchal rigidity = pathognomonic sign of meningitis
- change in mental status (delirium, confusion; test by mini-mental; level of consciousness)
- headache (common, typically severe and generalized)
- pts are very ill and often present soon after onset of symptoms (24 hrs)
- course of illness varies from progression over hours to several days
- photophobia
- nausea
- vomiting
- seizures (more in kids)
- focal neurological deficits (including cranail nerve palsies)
- papilledema (edges of optic disc are blurred)
- myalgias
- maculopapular rash that progresses to petechiae and palpable purpura in meningococcal meningitis
95% sensitivity for clinical features of 2 of the following symptoms
- fever
- neck stiffness
- altered mental status
- headache
93% sensitivity for lab features of
cerebrospinal fluid with WBC count > or = 100 per microL
87% sensitivity for this clinical feature
headache
83% sensitivity for this clinical feature
neck stiffness
77% sensitivity for this clinical feature
fever > or + 100.4F (38C)
44% sensitivity for this clinical feature
triad of fever, neck stiffness, and altered mental status