CNS Infections Flashcards
(107 cards)
1
Q
what all does meningitis involve?
A
- subarachnoid space
- brain
- blood vessels
- ventricular system
2
Q
types of meningitis
A
- aseptic: viral
- bacterial
- other: fungal, protozoa, spirochetes, helminths
3
Q
how is meningitis most commonly spread?
A
- hematogenously
- blood stream invasion from respiratory tract
4
Q
what big 3 things do you have to watch out for in the risk of meningitis?
A
- otitis media (progressing to mastoiditis)
- odontogenic
- sinusitis
5
Q
other RFs for meningitis
A
- head trauma
- anatomical meningeal defects
- neurosurgical procedures
- cancer
- alcoholism
- immunodeficiency
6
Q
most common etiology of meningitis at 0-3 months
A
- group B strep
- E. coli
- viral: HSV, enteroviruses, CMV
7
Q
common enteroviruses
A
- coxsackie
- rhinovirus
- polio
- ECHO
- entero
8
Q
most common etiology of meningitis at 3 months to 3 years
A
- nisseria meningitidis
- strep pneumoniae
- TB
- viral: enteroviruses, HSV
9
Q
most common etiology of meningitis at 3-12 years
A
- strep pneumoniae
- nisseria meningitidis
- viral: enteroviruses, adenoviruses, HSV
- fungal
- mycobacterium (TB)
- spirochetes
- protozoans
- helminths
10
Q
meningococcal vaccine
A
- not required in all states
- usually required before living in the dorms
11
Q
classic triad of sx in meningitis
A
- fever
- stiff neck
- altered mental status
*doesn’t really translate to real life - low sensitivity
12
Q
nearly all patients w/ bacterial meningitis have a least 2 of the following:
A
- fever
- HA
- stiff neck
- altered mental status
13
Q
clinical features of meningitis in neonates/children
A
- **bulging fontanelle
- fever
- vomiting
- lethargy
- irritability
- poor feeding
- increase head circumference
14
Q
every kid that comes into the ER under 2-3 months w/ a fever gets what?
A
- sent to ER
- septic w/u
15
Q
clinical features of meningitis in older children/adults
A
- fever
- HA
- neck stiffness
- confusion
- nausea/vomiting
16
Q
more advanced stage clinical features of meningitis in older children and adults
A
- lethargy
- photophobia
- ophthalmoplegia
- Bell’s palsy
- meningeal signs: kernig’s, brudzinski’s, nuchal and spinal rigidity
17
Q
kernig’s sign
A
- reflex contraction and pain in hamstrings upon extension of leg that is flexed at the hip
- tip: looks like a K
18
Q
nuchal rigidity
A
- unable to place chin on sternum
- involuntary contraction of neck muscles
19
Q
spinal rigidity
A
- stiffness of back
- involuntary spasms of erector spinae muscles (opisthotonus)
20
Q
brudzinski’s sign
A
- reflex flexion of hips and knees upon flexion of neck
- severe neck stiffness causes a pts hips and knees to flex when neck is flexed
21
Q
making the diagnosis of meningitis
A
- CBC
- blood cultures
- lumbar puncture
- CT
- electrolytes
- x-ray
- EEG
22
Q
blood cultures for meningitis
A
- have to get 2 draws from 2 different sites separated by 15 minutes
- any positive out of that means positive diagnosis
23
Q
when to do lumbar puncture
A
only after CT to r/o a space occupying lesion
24
Q
what to test the CSF for after obtaining lumbar puncture
A
- CSF profile (protein, glucose etc.)
- CSF gram stain
- CSF C&S
25
nl and elevated opening pressures when getting lumbar puncture
- nl: 10 cm
| - elevated: >25cm
26
which CSF sample should be sent for C&S?
- the last one obtained during the lumbar puncture
| - don't want skin contaminate from the tap
27
where do you insert the needle in a spinal tap?
b/w the 3rd and 4th lumbar vertebrae
28
why do you have to get a CT before getting lumbar puncture?
the presence of a space occupying lesion could cause a brainstem herniation if a spinal tap was preformed
29
automatic signs that warrant a CT
- papiledema
- seizures
- focal neurological findings
- immunocompromised pts
- moderate to severely impaired LOC
30
what to do while waiting to get CT
- get blood cultures
- start abx and steroids
- cut off is 4 hours for giving abx and affecting CSF results
31
meningitis CSF profile bacterial vs viral
| -glucose
- bacterial: decreased
| - viral: normal to low
32
meningitis CSF profile bacterial vs viral
| -protein
- bacterial: significantly increased
| - viral: mildly increased
33
meningitis CSF profile bacterial vs viral
| -white cell count
- bacterial: increased (200-20,000)
| - viral: increased (25-2000)
34
meningitis CSF profile bacterial vs viral
| -predominant cell
- bacterial: PMNs
| - viral: lymphocytes
35
meningitis CSF profile bacterial vs viral
| -pressure
- bacterial: markedly elevated
| - viral: slightly elevated
36
emergency tx for marked increase in ICP
- hyperventilation (not as useful as they used to think)
- mannitol
- drain CSF
- +/- dexamethasone 10 mg
37
how does mannitol work?
- changes the osmolality of the blood to pull fluid out of brain
- this is done in the ICU not rural OK
38
tx of meningitis
- isolation: until 24 hrs after C&S
- monitor vitals: glucose, acid-base, volume status
- +/- anticonvulsants
39
tx of viral meningitis
supportive care - can usually go home
40
initiating tx before getting culture back for neonates (<1mo)
ampicillin + 3rd generation chephalosporin
41
initiating tx before getting culture back on infants/children/adults
3rd generation cephalosporin + vancomycin + ampicillin
42
prevention of meningitis
- childhood immunizations: h. flu, s. pneumonia
| - immunizations against n. meningitidis in special circumstances
43
in which case do you need to give prophylactic tx for the household and close contacts of someone w/ meningitis?
**nisseria meningitidis
| also listed is h. flu but not as big of a deal
44
complications after meningitis
- HA
- seizures
- cerebral edema
- hydrocephalus
- deafness
45
death outcomes in bacterial meningitis
- s. pneumoniae - 25%
- n. meningtidis - 10%
- h. flu - 5%
46
what sx are associated w/ a worse prognosis in meningitis?
- extreme ages
- delayed diagnosis and tx
- stupor and coma
- seizures
- focal neurological signs
47
nisseria meningitidis bacteria type
- gram negative
- aerobic
- encapsulated diplococcus
48
where do nisseria meningitidis commonly live?
- mucosal surfaces of the human nasopharynx
| - urogenital tract and anal canal to lesser extent
49
population with high % of n. meningitidis
- military camps
| - college dorms
50
who has increased likelihood of invasive disease in meninococcal meningitis?
- immunocompromised
- smokers
- concurrent viral infection
- crowded living conditions
51
unique clinical sign of meningococcal meningitis that sets it apart from the other kinds
petechial rash
52
describe the petechial rash seen in meningococcal meningitis
- more common in younger pts
- trunk, legs, mucous membranes, conjunctivae
- purple-red in color
- does NOT blanch to pressure
53
what could a petechial rash progress to?
waterhouse-friderichsen syndrome
54
waterhouse-freiderichsen syndrome
- large petechial hemorrhages in the skin and mucous membranes and adrenal glands
- fever
- septic shock
- DIC
55
immunoprophylaxis for meningococcal meningitis
- vaccination for close contacts of pts infected
| - mass immunization of selected communities
56
chemoprophylaxis for meningococcal meningitis
- not recommended during epidemics
| - can use in people in close contact w/ pts
57
tx and dose for adult chemoprophylaxis for meningococcal meningitis
- cipro
| - single dose 500 mg
58
tx and dose for children chemoprophylaxis for meningococcal meningitis
single IM injection of ceftriaxone
59
what med can you not give kids under the age of 17?
fluoroquinolones
60
complications d/t meningococcal meningitis
- DIC
- septic arthitis
- pericarditis
- pneumonia
- communicating hydrocephalus
61
define encephalitis
-inflammation of brain matter d/t direct invasion or hypersensitivity to a pathogen
62
MC cause of encephalitis
- viral:
- HSV
- mumps
- measles
- rabies
- arboviruses (west nile)
- HIV
- polio
- CMV
63
other possible causes of encephalitis
- bacterial
- spirochetal: syphilis, RMSF
- mycobacterial
- fungal
- parasitic
64
how does encephalitis present?
essentially the same as meningitis
65
diagnosis of encephalitis
- lumbar puncture
- CT/MRI/EEG
- serologic studies
- brain tissue biopsy (rarely get to this stage)
66
what would encephalitis look like on a CT
empyema w/i spaces of the brain
67
encephalitis tx
- tx the cause if you can ID it
- monitor vitals
- supportive care
- poor prognosis
68
herpes encephalitis
- acute, necrotizing, asymmetrical hemorrhagic process
| - involved medal temporal and inferior frontal lobes
69
type of herpes commonly associated w/ herpes encephalitis
- herpes simplex 2
| - but simplex 1 is more aggressive and more lethal
70
signs and sx of herpes encephalitis
- same as encephalitis
| - temporal lobe dysfunction: olfactory hallucinations and behavioral disturbances
71
tx for herpes encephalitis
IV acyclovir
72
where does viral DNA exsist within the CNS?
trigeminal ganglion
73
possible transmission of herpes encephalitis
- olfactory transmission (hence temporal lobe)
| - you have active lesion, you touch it, then pick nose
74
when is a newborn at increased risk of HSV encephalitis?
-if mom is infected during 3rd trimester
or
-active lesion in vagina
75
define brain abscess
- focal infection
- begins when organisms are inoculated into brain parenchyma
- usually from a site distant from the CNS
76
brain abscess can occur by what 3 mechanisms?
- direct extension
- hematogenous
- penetrating head injury or neurosurgery
77
examples of direct extension
spread of infection from:
- sinuses
- teeth
- middle ear or mastoid
78
hematogenous spread causing brain abscess
- seeding of brain occurs from distant infection sites and often results in multiple abcesses
- ex: IVDU
79
MC presenting symptom of brain abscess
HA
80
other clinical features of brain abcess
- focal neurologic deficit
- seizure
- mental status change
- n/v, stiff neck if cerebral edema
81
exam findings with brain abscess
-focal neuro findings
-papilledema (advanced disease)
possible in infants:
-bulging fontanelles
-irritability
-enlarging head circumference
82
lab to order w/ suspected brain abcess
- CBC and sed rate: not reliable but helpful
| - draw blood cultures
83
pathognomonic CT finding in brain abscess
ring enhanced lesions
84
tx for brain abscess
- assess need for intubation
- start abx ASAP
- control seizures aggressively
- neuro consult
85
abx for direct extension brain abscess
penicillin G + metronidazole + 3rd generation cephalosporin
86
abx for hematogenous spread brain abscess or from penetrating trauma
nafcillin + metronidazole + 3rd generation cephalosporin
87
abx for postop brain abscess
vancomycin + ceftazidime or cefepime
88
abx for brain abcess when there is no predisposing factors
metronidazole + vancomycin + 3rd generation cephalosporin
89
different classifications of neurosyphilis
- asymptomatic neuroinvasion
- meningovascular syphilis
- tabes dorsalis
- general paresis
90
asymptomatic neuroinvasion type neurosyphilis
- CSF abnormalities w/o sx or sign of neurological involvement
- no clinical significance
91
meningovascular syphilis
- inflammatory changed in meninges or vascular structures of brain
- HA, cranial nerve palsies, ocular changes and possible CVAs
92
tabes dorsalis
- chronic, progressive degeneration of parenchyma of posterior columns of SC and posterior sensory ganglia and nerve roots
- causes impairment of proprioceptions and vibration sense, argyll robertson pupils, weakness and unsteady gate
93
general paresis
-generalized involvment of cerebral cortex causing poor concentration, memory loss, dysarthria, tremor in fingers and lips, HA, and personality changes
94
classic CSF findings in neurosyphilis
- elevated total protein
- lymphocytic pleocytosis
- positiv VDRL (venereal dz research lab)
95
what lab to you continue to check in neurocyphilis
VDRL
| -it is essentially a titer
96
tx for neurosyphilis
- high dose aqueous penicillin X 10-14 days
| - then move to 2.4 million units benzathine penicillin IM weeks X 3 weeks
97
what is the fungal infection you have to watch for?
cryptococcosis
98
describe the fungus crytococcus neoformans
- encapsulated yeast
| - meningitis is the MC clinical presentation but can have pulmonary infection
99
who will present w/ cryptococcus infection
| **BOARDS
- HIV pts
| - CD4 count <50
100
pathogeneis sof cryptococcus
- organism is inhaled causing pulm infection first
| - if host defenses not adequate then infection can disseminate
101
clinical manifestations of cryptococcosis
- CNS: HA, nuchal rigidity, lethargy, confusion, photophobia, papilledema, n/v
- fever in 1/2 cases
102
diagnosis of cryptococcosis
- culture
- CSF stain
- latex agglutination test
103
tx of cryptococcosis
-amphotericin B + flucytosine X 6 weeks
then
-fluconazole or itraonazole for pulmonary infection
104
naegleria fowleri
- primary amebic meningoencephalitis
- "brain eating ameba"
- 97% fatal
105
where does naegleria fowleri thrive?
warm freshwater lakes and streams that aren't flowing well - also soil
106
mode of naegleria fowleri infection
- penetrates through nasal mucosa
| - NOT by swallowing water
107
tx of naegleria fowleri infection
amphotericin B
