Bacterial Infections of the CNS I (meningitis/encephalitis) Flashcards
Nearly 100% of patients with meningitis will present with two of these four symptoms
fever, headache, stiff neck (nuchal rigidity), and altered mental status
Approximately half of all patients with meningitis present with
Fever, Headache, and Stiff Neck
Labs for Dx of Meningitis
gram stain of CSF, cultures, latex agglutination
Bacterial meningitis or Viral Meningitis/encephalitis? presence of PMNs
bacterial
Bacterial meningitis or Viral Meningitis/encephalitis? presence of mono/lymphos
viral
Bacterial meningitis or Viral Meningitis/encephalitis? rare PMNs
Viral
Bacterial meningitis or Viral Meningitis/encephalitis? increased protein
bacterial
Bacterial meningitis or Viral Meningitis/encephalitis? decreased glucose
bacterial
Bacterial meningitis or Viral Meningitis/encephalitis? normal glucose
viral
Bacterial meningitis or Viral Meningitis/encephalitis? increased pressure
bacterial
Bacterial meningitis or Viral Meningitis/encephalitis? normal or slightly increased protein and pressure
viral
Tx: bacterial meningitis
empirical antibiotic therapy (specific after organism identified)
majority of bacterial meningitis cases occur in
infants and children
common agents of bacterial meningitis
S. pneumoniae (50%), N. meningitides (25%) Group B Strep, Listeria monocytogenes, Haemophilus influenzae
Group B strep meningitis is common in
the very young and the very old
incubation of 3-4 days with abrupt onset of fever, hypotension and rash, headache, neck stiffness
meningococcal disease
gram + coccus catalase -, frequently grows in chains (liquid culture), oval cells, polysaccharide capsule
Streptococcus pneumoniae
round mucoid colonies on blood agar, alpha-hemolytic
Streptococcus pneumoniae
susceptible to optochin, susceptible to bile
Streptococcus pneumoniae
most common cause of vaccine-preventable death in the US
pneumococcal disease-causes bacterial meningitis among infants and and young children
Streptococcus pneumonia clinical syndromes
pneumonia, bacteremia, meningitis, otitis media
Neurological sequelae is common among survivors of bacterial meningitis caused by this bacteria
Streptococcus pneumonia
Streptococcus pneumoniae causes bacterial meningitis in the
very old and very young
pneumococcal bacteria bind these in the oropharynx
choline binding proteins of the bacterial cell wall bind carbohydrates on the surface of epithelial cells
pneumococcal bacteria destroy ciliated epithelial cells and degrade secretory IgA using
pneumolysin and IgA protease (pneumolysin also interferes w/ macrophages)
characterized by an acute onset (within hours), high mortality (30%), and neurological sequela (10-20%)
pneumococcal meningitis
pneumococcal meningitis Dx
gram-stain CSF, latex-agglutination (presence of capsular antigens), culture, biochemical analysis, susceptibility testing
Tx: of pneumococcal meningitis
vancomycin w/ a cephalosporin (modify after identification, treat for 10-14 days)
Prevention of pneumococcal meningitis
PPV23 purified capsular polysaccharide antigen from 23 types of pneumococcus, PCV13
What is one problem with the PPV23 vaccine?
It is not very effective in children under the age of 2
Who is the PPV23 vaccine recommended for?
adults over 65, persons over 2 with chronic illness, asplenia, immunocompromised, HIV infection, environments or settings with increased risk
What vaccine is recommended for kids under two for pneumococcal meningitis?
PCV7, PCV13-pneumococcal conjugate vaccine-polysaccharide conjugated to nontoxic diphtheria toxin-very effective against invasive disease (less effective against pneumonia and acute otitis media)
What are the recommendations for the PCV13 vaccine?
routine vaccination of children-doses at 2, 4, 6, months, booster dose at 12-15 months
gram-negative diplococcus, kidney bean appearance, polysaccharide capsule (12 serotypes), LOS
Neisseria meningitides
Neisseria meningitides-oxidase? catalase? glucose? maltose?
oxidase and catalase positive, ferments both glucose and maltose
cause of bacterial meningitis that is epidemic in sub-Saharan Africa
Neisseria meningitides
Neisseria meningitides most commonly manifests as
bacteremia, meningitis (also as pneumonia, arthritis, otitis media, epiglottitis)
How is neisseria meningitides transmitted?
aerosolized droplets
This type of meningitis is commonly associated with people living in close quarters such as in househoulds, military barracks, schools, and dormitories
bacterial meningitis caused by Neisseria meningitides
In meningitis caused by neisseria meningitides fatality rates are highest in
adolescents
undergo facilitated uptake by epithelial cells
Neisseria meningitides
Complications include endotoxemia-organ failure, DIC
meningococcal disease (neisseria meningitides)
May occur with or without meningitis, bacteria in the blood accompanied by fever, purpuric rash hyptoension and multiorgan failure
Meningococcemia
results from hematogenous dissemination-presentation includes fever, headache, stiff neck
Meningococcal Meningitis
Dx: of meningococcal meningitis
recognize clinical signs and lab identification (gram stain of CSF/blood) culture, biochemical analysis, susceptibility testing, may also test lesion material
Tx: meningococcal meningitis (N. meningitides)
penicillin (may begin with vancomycin and/or a cephalosporin before identification)
What is recommended for family members, classmates, and co-workers of those infected with meningococcal meningitis (N. meningitides)?
prophylactic treatment
What are the downfalls to the MPV4 vaccine for meningococcal meningitis?
only protects against A, C, Y, W-135 not B serotype, and is not effective in children under the age of 2, produces little affinity IgM, little IgG, not recommended for routine vaccination
The meningococcal polysaccharide vaccine is not recommended for routine vaccination but is recommended for certain high-risk populations such as these
terminal complement deficiency, functional or anatomic asplenia, certain laboratory workers, traverls to and US citizens residing in countries in which N. meningitidis is hyperendemic or epidemic
meningococcal conjugate vaccine (MCV4) is approved for ages 1-55 and protects against
A, C, Y, W-135 but not B serotype (conjugated to non-toxic diptheria toxin subunit)
Unlike the other meningococcal vaccine this vaccine has booster response observed and a higher affinity antibody response/higher IgG response
MCV4
Vaccination is recommended for students entering high school and is mandated by law in a dozen states for those entering college
MCV4
