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61 Cards in this Set
- Front
- Back
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You grow something on culture. It is a gram neg. diplocci. It grew best at 35-37 degrees in a CO2 enriched environment. It is oxidase positive and aerobic.
WHO DAT IS? |
Neisseria meningitidis
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N. meningitidis
Major antigens |
1. capsular polysaccharides (A,B,C,Y,W-135)
-antigenic, antiphagocytic 2. Outer membrane proteins: Opa, Opc, PorA, PorB 3. LOS 4. Pili |
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Patient presents with:
-Petechiae and purpura -Hypotension -Intravascular thrombosis -blood culture positive for gram neg. diplococci, oxidase pos, non-glucose fermenting dx? What is happening? |
Fulminant meningococcemia
N. meningitidis infection in bloodstream |
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Fulminant meningococcemia
Complications |
-DIC
-Loss of limbs/digits/skin from ischemic necrosis -Waterhouse Friederichesen occasionally (hemorrhage into adrenal) |
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What happens if Nieserria Meningitides infects the CSF
How did it get there? |
meningitis
Hematogensous spread from nasopharynx to meninges |
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Patient has headache, meningismus, fever. CSF culture positive for Niesseria. What are 3 complications you fear?
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1. Mental retardation
2. Deafness 3. hemparesis |
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Most patients with blood cultures positive for Niesseria do not get fulminant meningococcemia.
What determines if you get FM? |
Polymorphisms in several inflammation/clotting genes
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Meningococcus
a. reservoir b. transmission c. incidence |
a. humans
b. person to person via respiratory droplets c. 1 case per 100k per year |
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5 factors that increase meningococcal transmission
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1. close contact with someone with meningococcal disease
2. crowding 3. cigarette smoke exposure 4. recent viral URI 5. terminal complement component deficiencies |
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Serogroup of meningococcus highest in
a. Sub saharan africa b. usa |
a. A
b. B and Y |
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breakfast
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le petit dejeuner
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Host factors that prevent infection of N. meningitidis
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antibodies
complement phagocytes |
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What causes fulminant meningitidis
What can you find in blood? |
Shedding of LOS in blood --> massive inflammatory response
Should find: proinflammatory mediators (TNFa, IL1, IFNg, IL-8) and antiinflammatory mediators (IL-1 receptor agonist, soluble TNF receptors, IL-10) |
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Patient has CSF with 100-1000x increase in
endotoxin, IL-6, TNFa, IL-1b, IL-1Ra, and IL-10 Where is the inflammatory response |
Subarachnoid space and surrounding structures
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How do you diagnose N. meningitidis
what should you see on culture |
Gram stain and culture CSF or blood, PCR, monoclonal antibody tests
Fastidious, grow on chocolate agar with high CO2 |
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2 types of N. meningitides vaccines.
Who should take them/what do they protect against |
Polysaccharide vaccine - prevents infections of serogroups A,C,Y, and W-135
Polysacc-dephtheria toxoid conjugate vaccine - for people age 11 to 55, protects longer |
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For whom is n. meningitides vaccine recommended?
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those with complement deficiency
-sickle cell anemia -splenectomy -military recruits -travelers to Sub Saharan Africa -College freshman about to enter dorms CLOSE CONTACTS WITH INFECTED PEOPLE |
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Your patient has n. meningitides. What should you do for his family?
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Postexposure prophylaxis with refampin, ciprfloxacin, or IM ceftriaxone
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Name that pathogen
-small, pleomorphic, gram-neg. bacilli -Requires factor X (hemin) and V (NAD) to isolate in lab |
Haemophilus influenzae type B
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Major encapsulated serotype of H. influenzae
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type B
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Where is h. influenzae found in unvaccinated children?
How is it transmitted? |
Nasopharynx
Transmitted by inhalation of airborne droplets or direct contact with oro and nasopharyngeal secretions |
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vaccination for h. influenzae protects against which serotype
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type b only
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What are some diseases caused by h. influenzae
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1. meningitis - most common cause in countries w/o vaccination
2. bacteremia 3. epiglottitis - older kids 4. pneumonia 5. cellulitis 6. septic arthritis |
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what is the primary virulence factor of h. influenzae?
what does it composed of |
polysaccharide capsule, prevents phagocytosis
composed of pohosphoribosylribitol phosphate |
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Some people are immune to h. influenzae type b.
WHAT MAKES THEM SO SPECIAL |
serum has antibody to type b polysaccaride capsule --> allows opsonization and killing by complement
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You suspect h. influenzae infection.
How can you diagnose it? What should you avoid that would mess up the diagnostic tests? |
Culture blood and CSF
organism will not grow on blood, but will grow on chocolate (needs hemin and NAD) Antibiotics can give a false-negative culture |
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how can you prevent h. influenzae infection
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Vaccination
-polysaccharide or conjugate |
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Your patient has h. influenzae type B disease. What should you do for his baby child?
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rifampin prophylaxis --> eliminates nasopharyngeal colonization
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What is the leading cause of meningitis in the US
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streptococcus pneumoniae
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What organism is this?
Gram positive, lancet-shaped diplococci, grows in pairs -a-hemolytic, optochin sensitive -grows at 35-37 deg. -grows on sheep blood -requires CO2 |
streptococcus pneumoniae
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streptococcus pneumoniae
a. reservoir b. transmission |
a. humans
b. person to person through respiratory secretions |
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patient populations at risk for developing invasive pneumococcus disease
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1. acloholics, smokers
2. age <2 or >65 3. cochlear implant recipients 4. sickle cell 5. splenectomy 6. immunosuppression 7, hypo Ig COCHLEAR IMPLANT, CSF LEAK |
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You diagnose pneumoccoal menigitis. What complications do you fear?
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-Permanent sensorineural hearing loss
-permanent neurological defecits -seizure disorders |
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how does presentation of pneumococcal meningitis differ in adults and neonates?
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adults - typical presentation
neonates- cardinal signs often absent |
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You suspect pneumococcus infection.
What should you do to diangose? What should you avoid doing? |
Perform LP --> culture or antigen detection assay
Don't give antibiotics, as that may give you a false-negative result |
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What does vaccination for pneumococcus do?
Who should be vaccinated? |
prevents bacteremia
adults: >60yo, chronic lung disease, diabetes, asplenia children |
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how does pneumoccus vaccine differ for kids and adults?
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adults - 23 valent polysacc vaccine
kids - vaccine against 7 pediatric serotypes |
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What organism is this?
-Gram pos. cocci -grows in long chains -B-hemolytic, bacitracin resistant -Optimal growth at 35-37 deg, medium with sheep blood |
Strep agalactiae (group B)
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Group B strep
a. reservoir b. transmission c. risks for development of disease |
a. humans, cattle
b. neurosurgery, neonates can acquire from maternal genital tract at birth c. lack of Ab to capsule, premature delivery, prolonged rupture of membranes in infected mom, Diabetes |
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Clinical syndromes associated with group B strep
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1. Major cause of neonatal sepsis/bacteremia, Neonatal meningitis (not in older kids or adults)
2. UTI 3. celluluitis 4. Pneumonia etc |
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Virulence of Group B strep
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polysacc capsule, hemolysins, digestive enzymes, hyaluronate lyase, antigenic variation ,degradation of immune components
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What organism is this?
-Gram pos. cocci -grows in long chains -B-hemolytic, bacitracin resistant -Optimal growth at 35-37 deg, medium with sheep blood |
Strep agalactiae (group B)
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Treatment for Group B strep
What can you use for prophylaxis |
Pen G or ampicillin
Chemoprophylaxis by giving neonates small dose of ampicillin |
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Group B strep
a. reservoir b. transmission c. risks for development of disease |
a. humans, cattle
b. neurosurgery, neonates can acquire from maternal genital tract at birth c. lack of Ab to capsule, premature delivery, prolonged rupture of membranes in infected mom, Diabetes |
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Clinical syndromes associated with group B strep
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1. Major cause of neonatal sepsis/bacteremia, Neonatal meningitis (not in older kids or adults)
2. UTI 3. celluluitis 4. Pneumonia etc |
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Virulence of Group B strep
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polysacc capsule, hemolysins, digestive enzymes, hyaluronate lyase, antigenic variation ,degradation of immune components
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Treatment for Group B strep
What can you use for prophylaxis |
Pen G or ampicillin
Chemoprophylaxis by giving neonates small dose of ampicillin |
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What is the pathogen?
-gram positive rod, unencapsulated -b-hemolytic -non spore forming -facultatively intracellular -associated with deli meat |
Listeria monocytogenes
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Listeria
for whom does it cause meningitis? |
adults who are alcoholics or immunocompromised
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Listeria
virulence |
intrenalin (host cell division), hemolysins, ActA for motility in host cells, phosphlipase, Zn-dependent protease
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Listeria
Host factors |
e-cadherin
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Listeria
How does it lead to disease |
Crosses intestinal, placental, and BBB
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Patient has mild meningitis symptoms, slight neck stiffness
-CSF shows motile rods, gram positive dx? |
listeria
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Treat listeria
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ampicillin + gentamycin
cook food completely pregnant women should avoid deli meat |
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Meningitis in immunocompetent age < 3 mo
a. likely pathogens b. antibiotics |
a. strep agalactiae, e. coli, listeria
b. ampicillin + cephalosporin (broad) |
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Meningitis in immunocompetent age 3 mo - <18yr
a. likely pathogens b. antibiotics |
a. n. meningitidis, s. pneumoniae, h. influenze b
b. broad spectrum cephalo + vancomycin |
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Meningitis in immunocompetent age < 18-50
a. likely pathogens b. antibiotics |
a. s. pneumoniae, n. meningitidies
b. broad spectrum cephalosporin + vancomycin |
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Meningitis in immunocompetent age > 50
a. likely pathogens b. antibiotics |
a. s. pneumoniae, listeria, gram neg. bacilli
b. ampicillin+ broad spectrum cephalosporin + vancomycin |
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Meningitis in immunosuppressed adults
w/ impaired cellular immunity a. pathogen b. treat |
a. listeria or gram neg. bacilli
b. ampicillin + ceftazidime |
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Meningitis in immunosuppressed adults
w/ head trauma, neurosurgery, CSF shunt a. pathogen b. treat |
a. staph, gram negs, or s. pneumoniae
b. vancomcin + ceftazidime |
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Effect of glucocoriticoids given before antibiotic therapy
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prevents sensorineural hearing loss in children with H. influenzae type b meningitis
Improves survival in adults with pneumococcal meningitis |
