CNS Infections-Kozel Flashcards
1
Q
What are routine tests of CSF?
A
WBC count w/ differential glucose conc'n protein conc'n gram stain bacterial culture
2
Q
What are some specific tests you can perform on CSF w/ suspicion?
A
Nucleic acid amplification Stain and culture for AFB VDRL test India ink negative stain Cryptococcal polysaccharide antigen Fungal culture Viral culture
3
Q
What could change the white blood cell count?
A
inflammation, immune response
needs to be adjusted if evidence of blood in CSF
4
Q
How can glucose be altered in CSF findings?
A
can be decreased
b/c of increased glycolysis by WBC & bacteria
increased metabolic rate of brain & spinal cord
altered glucose transport b/w blood & CSF
5
Q
How can protein be altered in CSF findings?
A
protein can be increased
disruption of BBB
needs to be adjusted if you see blood in CSF b/c serum has protein
6
Q
What are 2 contraindications for lumbar puncture?
A
papilledema-shows increased cranial pressure
neurological suggestions of intracranial mass
7
Q
WHat is acute meningitis?
A
inflammation of meninges that has its onset of symptoms over hours to several days
8
Q
What is aseptic meningitis?
A
meningitis w/o an apparent cause after routine stains & cultures of CSF
9
Q
What are the symptoms of meningitis?
A
triad: headache, neck stiffness, fever
also confusion
vomiting
photophobia, phonophobia
10
Q
What are the main causes of viral meningitis?
A
enteroviruses
mumps virus
herpes virus
11
Q
What are the main causes of bacterial meningitis?
A
Haemophilus influenzae (7%) Neisseria meningitidis (16%) Streptococcus pneumoniae (61%) Streptococcus agalactiae (14%) Listeria monocytogenes (2%)
12
Q
What are the causes of spirochetal meningitis?
A
Treponema pallidum
Borrelia burgdorferii
13
Q
Other forms of meningitis?
A
protozoal & helminthic meningitis
14
Q
What is the pathophysiology of bacterial meningitis?
A
nasopharyngeal colonization local invasion intravascular survival meningeal invasion induction of subarachnoid space inflammation altered BBB cerebral edema increased ICP
15
Q
What does it mean that meningitis is vasogenic, cytotoxic, interstitial?
A
vasogenic: increased BBB permeability
cytotoxic: swelling of cellular elements of brain
interstitial: obstruction of CSF flow
16
Q
Strep pneumonia after adhering to nasal mucosa can cause pneumonia….or if it gets into the bloodstream can cause?
A
meningitis
17
Q
If you have a kid, less than 1 mo…what are the likely bacterial pathogens for bacterial meningitis?
A
Strep agalactiae=group b strep
E coli
listeria monocytogenes
klebsiella
18
Q
1-23 mo…which bacterial pathogens for meningitis?
A
S. agalactiae E. coli, Haemophilus influenzae Streptococcus pneumoniae Neisseria meningitidis
19
Q
2-50 yrs bacterial pathogens for meningitis?
A
S. pneumoniae
N. meningitidis
20
Q
Over 50 years…bacterial pathogens for meningitis?
A
S. pneumoniae
N. meningitidis
L. monocytogenes
Aerobic gram-negative bacilli
21
Q
Prior to vaccinations…what was a dominant cause of meningitis?
A
H. influenza
22
Q
With meningitis what good thing happens for antibiotic penetration of BBB?
A
inflammation causes increased penetration of BBB
23
Q
Why might it be a challenge to give a patient corticosteroids & antibiotics w/ meningitis?
A
corticosteroids shut down BBB penetration
might need to raise dosage of antibiotics
24
Q
What are features of antibiotics w/ good BBB penetration?
A
Low molecular weight Low degree of ionization at physiological pH High lipid solubility Low degree of protein binding Absence of active efflux systems
25
What is the WBC count, cell type, glucose, protein levels w/ a viral meningitis?
WBC: 50-1000
Cell type: mononuclear
Glucose: >45
Protein: <200
26
What is the WBC count, cell type, glucose, protein levels w/ a bacterial meningitis?
WBC count: 1000-5000
Cell type: neutrophilic
Glucose: <40
Protein: 100-500
27
What is the WBC count, cell type, glucose, protein levels w/ a TB meningitis?
WBC: 50-300
Mononuclear
Glucose: <45
Protein: 50-300
28
What is the WBC count, cell type, glucose, protein levels w/ a cryptococcal meningitis?
WBC: 20-500
Mononuclear
Glucose: 45
29
What is normal WBC count, cell type, glucose, protein levels w/o meningitis?
WBC: 0-5
Glucose: 50-80
Protein: 15-50
30
What is chronic meningitis?
onset of >4 weeks
signs of chronic inflammation in CSF
early symptoms: headache, nausea, decreased memory, comprehension
31
What are the difference in presentation w/ chronic meningitis v. acute meningitis?
onset more gradual
fever lower
lethargy & disability
immunocompromise
32
What are the bacterial causes of chronic meningitis?
Mycobacterium tuberculosis
Treponema pallidum
Borrelia burgdorferii
33
What are the mycoses that can cause chronic meningitis?
Cryptococcosis
Coccidioidomycosis
Histoplasmosis
Candidiasis
34
What are the parasites that can cause chronic meningitis?
Acanthamebiasis
Cysticerosis
Angiostrngylus cantonensis
35
What is encephalitis?
inflammation of brain parenchyma
neurologic dysfunction
fever & headache
altered mental status
36
What is the CSF profile in encephalitis?
lymphocytes elevated
normal glucose
elevated protein
37
What is the etiology of viral encephalitis?
```
Herpesviruses
(HSV-1 and HSV-2
Varicella-Zoster virus
CMV
HHV-6)
Arboviruses
HIV
Enteroviruses, primarily poliovirus
Rabies virus
```
38
What are non-viral causes of encephalitis?
```
Listeria monocytogenes
Rickettsia spp.
Ehrlichia spp.
Bartonella spp.
Mycoplasma pneumoniae
```
39
What is a brain abscess?
– focal, intracerebral infection that begins as a localized area of cerebritis and develops into collection of pus surrounded by a well-vascularized capsule
40
What is the source of a brain abscess?
spread from sinusitis, otitis media, mastoiditis
blood-borne
trauma
41
What are the symptoms of brain abscess?
headache, nausea, vomiting, focal neurologic findings
42
What is the bacterial etiology of a brain abscess?
Streptococcus spp. (70%) Enterobacteriaceae
S. aureus (10-20%) Pseudomonas spp.
Bacterioides spp. Nocardia asteroides
Prevotella spp. Mycobacterium spp.
Fusobacterium spp.
43
What is the fungal etiology of a brain abscess?
Aspergillus spp. Mucorales
Candida spp. Coccidioides spp.
Cryptococcus spp.
44
What are causative organisms of protozoal & helminthic brain abscesses?
Toxoplasma gondii (most common)
Neurocysticercosis – larval form of Taenia solium; developing world
Others: Trypanosoma cruzi, Entamoeba histolytica, Shistosoma spp.
45
What are the usual microbial isolates of a sinus & dental infection?
```
strep (anaerobic & aerobic)
bacterioides
prevotella
enterobacteria
s. aureus
```
46
What are the usual microbial isolates w/ penetrating trauma?
staph aureus
aerobic strep
enterobacteria
clostridium
47
What are the usu microbial isolates of a pulmonary infection?
```
fusobacterium
actinomyces
bacterioides
prevotella
nocardia
strep
```
48
What are the usual microbial isolates of congenital heart disease?
strep
| staph aureus
49
What are the usual microbial isolates of a HIV infection?
```
toxoplasma gondii
nocardia
mycobacterium
listeria monocytogenes
cryptococcus neoformans
```
50
What is the usual microbial isolate of a transplantation?
```
aspergillus
candida
mucorales
nocardia
toxoplasma gondii
```
51
What is the usual microbial isolate of neutropenia?
aerobic gram neg. bacilli
aspergillus
candida
mucorales
52
What are the features of neisseria?
gram neg. cocci
isolate on blood, chocolate agar, thayer-martin medium
produce indophenol oxidase
53
What is thayer-martin medium?
blood agar w/ selective antibiotics, gets rid of normal flora
54
What are easy ways to kill neisseria?
drying, sunlight, heat & chemicals
55
T/F Neisseria is oxidase +.
True.
56
What are the major groups of neisseria?
Group A
Group B-we don't make an antibody response to this.
Group C: endemic & occasional epidemic strain
Group Y & W
57
What makes up lipooligosaccharide?
Lipid A + Core
| Note: LPS would also have O antigens
58
Meningitis belt in subsaharan africa has which neisseria group?
Group A
59
T/F Meningococcal meningitis is a medical emergency.
True.
60
What are the virulence factors of N. Meningitidis?
capsule-antiphagocytic
LOS: toxic & produces inflammation.
outer membranes
pili
61
Why do you see petechiae & purpura w/ meningococcal meningitis?
b/c of virulence factors causing DIC & mini-hemorrhages.
62
How is LOS released from neisseria into the bloodstream?
as blebs
63
what is the pathogenesis of N. meningitidis?
```
nasopharynx
adheres
local or spreads via lymphatics to blood or meninges
capsule prevents phagocytosis
LOS does tissue damage & causes DIC
can get hemorrhage or shock
```
64
If you have a deficiency of terminal complement proteins (C5-C8)...what can happen?
multiple attacks by N. meningitis
65
Which samples will you send to lab for neisseria meningitides?
blood
CSF
nasopharynx swabs if you are looking for carriers
66
What are some differential tests for N. Meningitidis?
Gram negative diplococci
Oxidase positive
Oxidative production of acid from sugars, e.g., glucose and maltose
67
What is the epidemiology of N. meningitidis?
man-man via airborne droplets
young children: lack of antibody
college students or military recruits (stress, crowding, fatigue)
68
What is the carrier rate for N. meningitis?
1-40%
69
How can people have immunity to meningococcus?
anticapsular antibody
if immune-complement-mediated lysis & opsonization
anticapsular antibody
70
How can a person have a naturally occurring antibody to meningococcus?
carrier state of meningococcus
| carrier of cross-reacting bacteria, like E coli
71
What is the meningococcal vaccine?
tetravalent meningococcal polysaccharide vaccine
| covers groups A, C, Y & W-135 polysaccharides
72
MPSV4 vaccine covers which age group for meningococcus?
persons over 56 years old
73
MCV4 vaccine covers which age group?
adolescents 11-12 yrs
booster at 16-18 years
still covers Groups A, C, Y W-135
74
Which populations are at increased risk for meningococcus & thus need to be vaccinated?
```
college freshmen in dorms
microbiologists
military recruits
travelers to endemic regions
terminal complement deficiencies
asplenia
```
75
What does the vaccine for Group B target?
Factor H binding protein
76
Once again, what type of vaccine do we have for meningococcus?
multivalent purified capsular polysaccharide
| capsular polysaccharide-protein conjugate
77
What is the treatment for meningococcal meningitis?
3rd gen cephalosporin
OR
penicillin G or ampicillin
78
What is an example of a 3rd gen cephalosporin?
ceftriaxone or cefotaxime
79
What is the empirical antimicrobial treatment for purulent meningitis? <1 mo
ampicillin plus cefotaxime
OR
ampicillin + aminoglycoside
80
empirical antimicrobial treatment for purulent meningitis 1-23 mo?
vancomycin + a 3rd gen cephalosporin
81
What is the morphology of hemophilus?
very small gram negative rods
82
What are the important hemophilus species?
H. influenza
H. aegyptius-acute purulent conjunctivitis, brazilian purpuric fever
H ducreyi-venereal disease (soft chancre)
83
What is the antigenic structure of hemophilus?
```
capsular polysaccharide (antiphagocytic, types a-f)
type b causes disease, called polyribitol phosphate
```
84
Back to meningococcal treatment...if you treat contact people of those w/ meningitis what do you do?
Rifampin for family contacts of meningitis patient
85
What starts happening at 35-36 weeks of gestation?
IgG crosses the placenta & gives immunity
| premature births can be more susceptible to infections
86
What are the nutritional requirement of hemophilus?
X factor, found in blood
V factor, nicotinamide adenine dinucleotide
Chocolate Agar is good for growth w/ heating to release X & V factors from RBCs
**satellites with staph aureus
87
What are different types of H. influenza infections?
nasopharyngitis
epiglottis (can be an emergency)
pneumonia
meningitis-if it gets into the blood
88
What are the nontypeable strains of Hemophilus?
lack a capsule antigen
common
can cause middle ear infections
89
Aside from hemophilus...what else can cause middle ear infectionS?
strep pneumonia
| moraxella catarrhalis
90
What is the pathogenesis of Hib meningitis?
capsule antiphagocytic
type B blocks complement-mediated bacteriolysis
endotoxin-induces meningeal inflammation
91
How do you identify hemophilus in lab?
nasopharyngeal swab, blood, CSF
isolate w/ X & V factor requirements on chocolate agar
look for staph aureus satellite phenomenon
92
When people have Ab against Hib...how are they protected?
anticapsular Ab--opsonization & complement-mediated lysis
93
When is disease from Hib most common?
6 mo-3 years
prior to 6 mo: maternal antibody protects
after 3 years: exposed to Hib carriers
94
How is recommended to get Hib vaccine?
all children @ 2 mo
95
What type of vaccine do we have for H. influenza?
capsular polysaccharide protein conjugate
96
How do you treat a HIb infection?
broad spectrum cephalosporin w/ Good CNS penetration
cefotaxime or ceftriaxone
give rifampin to carriers or contacts
97
T-independent antigens?
```
polysaccharides
mouse doesn't need a thymus to make
high molecular weight
not degraded by enzymes
doesn't help kids in vaccines
```
98
What are general features of strep pneumonia?
gram +
encapsulated
grown on blood agar
99
What is the antigenic structure of strep pneumonia?
```
capsular polysaccharide
t independent antigen
quellung reaction
teichoic acid (c polysaccharide)
C-reactive protein--acute phase protein on cell wall
```
100
What are the different types of pneumococcal infection?
pneumonia
sinusitis
otitis media
meningitis
101
What is the pathogenesis of strep pneumonia infection?
Disease characterized by abrupt onset, toxicity, fulminant course and DIC
Disease due to inflammatory response to the bacterium and its products
The trick for the bacterium is to produce an inflammatory response but not be killed by it
102
Give more details about H. influenza biogroup aegyptius.
Etiologic agent of Brazilian purpuric fever
Invasive H. aegyptius following conjunctivitis
Acute onset of fever, vomiting and abdominal pain, followed by purpura, vascular collapse and death
103
Give more details about H. aegyptius.
– acute, purulent conjunctivitis
104
Give more details about H. ducreyi.
Chancroid (soft chancre); formerly rare in North America
Relatively common in Africa
Painful ulcers on genitalia
Probable co-factor in transmission of AIDS in Africa
105
empirical treatment purulent meningitis 2-50 yrs?
vancomycin + 3rd gen cephalosporin
106
empirical treatment purulent meningitis around 50 yrs?
vancomycin plus ampicillin plus a 3rd gen cephalosporin
