MICROBIOLOGY - CNS infections Flashcards
1
Q
what does pyogenic meningitis look like macroscopically
A
thick layer of suppurative exudate covering the leptomeninges over the surface of the brain
exudate in basal and convexity surface
2
Q
what does pyogenic meningitis look like microscopically
A
neutrophils in the subarachnoid space
3
Q
when should you consider listeria spp as the causative organism of pyogenic meningitis
A
over 60s immunocompromised diabetics alcoholics neonates
4
Q
what found is listeria assoc. with
A
soft cheese
5
Q
what organisms should you consider in pyogenic meningitis in neonates
A
listeria
group B strep
E. coli
6
Q
what organisms should you consider in pyogenic meningitis in children
A
H influenza
7
Q
what is the most common cause of pyogenic meningitis in 10 - 21 year olds
A
N. meningitidis
8
Q
what should be considered as cause of pyogenic meningitis in over 21s
A
strep pneumoniae
n. meningitidis
9
Q
what should be considered in over 65s as cause of pyogenic meningitis
A
strep pneumoniae
listeria
10
Q
what is the triad of meningism
A
fever
stiff neck
head ache
11
Q
what rash is seen in meningococcal meningitis
A
non blanching purpuric rash
12
Q
what are some s/s of meningitis
A
fever + stiff neck + headache rash fever photophobia, change in consciousness, lethargy, confusion vomiting
13
Q
what is kernigs sign
A
pain and resistance on passive extension of the knee with flexed hip
14
Q
what is the treatment of meningitis NPA
A
ceftriaxone + dexamethasone
15
Q
what is the treatment of meningitis PA
A
chloramphenicol + vancomycin + dexamethasone
16
Q
when should dexamethasone be started when treating meningitis
A
with or just before first course of antibiotics
- if already started can be started up to 12 hours after first dose
17
Q
if listeria cover required what should be added
A
amoxicillin
or co-trimoxazole alone if PA
18
Q
if recent travel to area of high rates of penicillin resistant pneumococci then what should be added
A
vancomycin or rifampicin
19
Q
if no organism is identified how long should treatment go on for
A
10 days
20
Q
how long should treatment go on for identified meningococcus
A
5 days (up to 7) ceftriaxone stop dexamethasone
21
Q
how long should treatment go on for identified pneumococcus
A
10 days (up to 14) ceftriaxone \+ 4 days dexamethasone
22
Q
how long should treatment go on for identified penicillin resistant/cephalosporin resistant pneumococcus
A
14 days ceftriaxone + vancomycin
+ 4 days dexamethasone
23
Q
why is vancomycin not used as a monotherapy
A
concerned about CSF penetration
24
Q
how long should treatment go on for identified listeria sp
A
at least 21 days amoxicillin
+ stop dexamethasone
25
how long should treatment go on for identified H influenza
10 days ceftriaxone
| + stop dexamethasone
26
how long should treatment go on for identified other gram negative bacteria
21 days agreed antibiotic regime
| + stop dexamethasone
27
what 4 organisms is decreased cell mediated immunity a risk factor for
listeria
strep pneumoniae
n. meningitidis
pseudomonas aeruginosa
28
neurosurgery / head trauma is a risk factor for what organisms
staph epidermidis
staph aureus
gram negative bacilli
29
fracture of the cribriform plate is a risk factor for what organism
strep pneumonia
30
basilar skull fracture is a RF for what organisms
strep pneumonia
h influenza
b-haemolytic strep group A
31
CSF shunt if a RF for what organisms
s. epidermidis
s. aureus
pseudomonas aeruginosa (aerobic GNR)
propionbacterium acnes
32
what are 4 complications of bacterial meningitis
purulence clusters at base of brain
invasion
cerebral oedema
ventriculitis/hydrocephalus
33
exudate can form around what cranial nerves
III and VI particularly vulnerable
34
what prevents meningitis becoming an abscess
pia
35
how can abscesses cause meningitis
cause secondary ventriculitis and hence meningitis
36
mycobacterium tuberculosis, nocardia asteroids and cryptococcus neoformans can be seen in what patients
immunocompromised patients
37
how is meningitis diagnosed
blood culture and coag
throat swab (meningococcal)
blood EDTA for PCR (meningococcal)
CSF fluid (LP) if clinically feasible
38
you should do a LP before/after antibiotics
after
39
what would CSF look like in bacterial meningitis
high WBC count
high neutrophils (may be lower if partially treated)
high protein
low glucose
40
how many tubes of CSF should be taken
4
41
what are the 3 tubes of CSF for
1 - haematology - cell count, differential
2 - microbiology - gram stain, culture
3 - chemistry - glucose, protein
4 - haematology
42
why might CSF be culture negative
pre-LP antibiotics
43
where is N. meningitidis found
throats of healthy carriers
44
how does gain access to the meninges
through the blood stream
45
where may N. meningitidis be found in the CSF
in leukocytes
46
what causes the symptoms of N. meningitidis
endotoxin
47
N. meningitidis disease occurs most in
young children
| 10 - 21
48
who gets vaccinated against N. meningitidis and why
army
| prevent epidemics in camps
49
apart from meningitis what other local disease can N. meningitidis cause
conjunctivitis
| arthritis
50
N. meningitidis is gram ___ and what shape
gram negative diplococci
51
H. influenza is part of what normal microbiota
throat
52
H. influenza requires what for growth
blood factors
53
what is the most common cause of meningitis in children under 4
H. influenza type b
54
is there a vaccine against H. influenza
yes
55
H. influenza is gram ___ and what shape
negative
| coccobacilli
56
where is strep pneumonia commonly found
nasopharynx
57
who is at risk of strep pneumoniae
```
hospitalised patients
CSF skull fracture
diabetics
alcoholics
young children
```
58
strep pneumoniae can be related to CNS devices such as
cochlear implant
59
some strep pneumoniae meningitis can occur secondary to what
strep pneumoniae pneumonia
60
is there a vaccine for strep pneumoniae
yes
61
strep pneumoniae is gram ___ and what shape
positive
| cocci in chains
62
listeria monocytogenes is gram ____ and looks like what
negative
| bacilli/rods
63
who is at risk of listeria monocytogenes
neonates
immunocompromised esp malignancy
> 55
64
what is the antibiotic of choice for listeria monocytogenes
amoxicillin
65
when can tuberculosis meningitis be seen
reactivation of latent TB in the elderly
66
what might you do if you suspect tuberculosis meningitis
chest XR to see if previous TB
67
what is the treatment for TB
isoniazide + rifampicin + pyrazinamide + ethambutol
68
name a type of fungal meningitis and when it might be seen
cryptococcal meningitis
| HIV when CD4 < 100
69
crytococcal meningitis will have an ____ picture on CSF and a subtle ____ presentation
aseptic
| neurological
70
what is the treatment for crytococcal meningitis
IV amphotericin / flucytozine
| fluconazole
71
true/false
| neutrophilic pleocytosis and low CSF glucose always means bacterial meningitis
false
72
what should be disrupted and swabbed or aspirated in early patient management for microscopy and culture
any petechial or purpuric rash
73
who should get a LP
all adults with suspected meningitis except if CI or there is confident clinical dx of meningococcal meningitis with typical meningococcal rash
74
what are some CI to LP
immunocompromised
papilloedema
focal neurological signs
altered consciousness
75
how can secondary cases of meningitis be prevented
report to public health
| prophylactic treatment for close contacts
76
what is the prophylaxis regimen for 12+ ages
600mg rifampicin 12 hourly 4 doses
or
ciprofloxacin single dose
77
what warnings should be given about rifampicin
red urine
reduced efficacy of OCP
staining of contact lenses
78
what is the prophylaxis regimen for children under 12
125mg ceftriaxone IV single dose
or
in children aged 3-11 can do 10mg/kg 4 doses orally of rifampicin
79
what vaccines for meningitis exist
n. meningitidis serogroups A and C
H influenza b
strep pneumonia
80
steroids have the most benefit in what type of meningitis
pneumococcal
81
when should steroids not be given
```
post surgical meningitis
severe immunocompromised
meningococcal
septic shock
allergy
```
82
who should undergo CT prior to LP to rule out raised ICP
```
immunocompromised
history of CNS disease
new onset seizure within 1 week of presentation
papilloedema
abnormal level of consciousness
focal neurological deficit
```
83
what is the most common cause of meningitis
viral
84
when is viral meningitis most common
late summer/autumn
85
what is the most common cause of viral meningitis
enteroviruses - ECHO virus
86
what other viruses cause viral meningitis
coxsackie
| HSV
87
how is viral meningitis diagnosed and treated
viral stool culture
throat swab
CSF PCR
supportive tx
88
what is aseptic meningitis
non pyogenic / pus forming
| infective or non-infective
89
what are some infectious causes of aseptic meningitis
syphilis, tb, crytococcus, hsv, lyme disease, others
90
what are some non-infectious causes of aseptic meningitis
vasculitis
sarcoidosis
drugs - cotrim, NSAIDs
91
what is encephalitis
inflammation of brain parenchyma
92
what causes encephalitis
HSV, VZV, CMV, HIV
93
how should encephalitis be investigated
LP, EEG and MRI
94
what would MRI in HIV show
bilateral focal temporal lobe enhancement
95
what should be started as prompt therapy in encephalitis
aciclovir
96
a single abscess is caused by
local extension e.g. mastoiditis or direct implantation e.g. skull fracture
97
multiple abscess are caused by
haematogenous spread
98
where do multiple abscesses tend to occur
at white grey matter border
99
what does an abscess look like
central necrosis
oedema
fibrous capsule
100
what are some s/s of abscess
fever
| raised ICP - headache, drowsy, focal neurological signs
101
how is abscess ix and tx
CT or MRI
aspiration for culture and tx
neurosurgical referral for urgent drainage
102
E coli is gram ___ and what shape
negative
| rods
103
how does bacterial meningitis cause hydrocephalus and raised ICP
inflammation of the leptomeninges and CSF within subarachnoid space - arachnoiditis which can later cause lack of CSF absorption
104
what causes progressive multifocal leukoencephalopathy
JC virus causing demyelination
105
what are some RF for JC virus
immunosuppression
AI disease
use of MS drugs e.g. tysabri
106
ix progressive multifocal leukoencephalopathy
LP: JC virus DNA and multifocal enhancing lesions on imaging
107
```
CSF: what kind of meningitis:
cells - lymphocytes
negative gram stain for bacteria
negative bacterial antigen detection
protein normal/slightly high
glucose normal
```
viral
108
```
CSF: what kind of meningitis:
cells - neutrophils/polymorphs
gram stain and bacterial antigen positive
high protein
low glucose
```
bacterial
109
```
CSF: what kind of meningitis:
cells - lymphocytes
gram stain for bacteria - positive or negative
bacterial antigen detection - negative
protein - high or very high
glucose - low
```
TB
