Transcript CNS Infections - Cleveland Clinic

CNS Infections
11-23-04
Chapter 235
Bacterial Meningitis
Epidemiology
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400 per 100,000 in neonates
1-2 per 100,000 in adults
S pneumoniae & N meningitidis m/c
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HIB vaccine has been very effective
Mortality
5% in children beyond infancy
 25% in neonates and in adults
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Pathophysiology
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S. pneumonia and N. meningitidis (and H.
influenzae) are encapsulated which provides
them with increased ability to invade BBB
Upper airway bloodstream subarachnoid
space subcapsular constituents trigger
inflammation fever, meningimus, change in
MS brain/meningeal edema decreased CSF
drainage hydrocephalus increased ICP
ICP>CPP
Clinical Features
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25% of adult cases “classic”
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Rapid development of
Fever
 HA
 Stiff neck
 Photophobia
 Change in MS
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Nonspecific signs/symptoms in very young/old
25% will develop seizures
Clinical Features
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History
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Living conditions
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College dorm/barracksN meningitidis
Trauma
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Recent neurosurgeryStaph/gram(-) rod
Immunocompetence
 Immunization hx
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NoneHiB
Antibiotic use
Clinical Feratures
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Physical Exam
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Brudzinski
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Kernig
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Flex hip, ext knee hamstrings contract
Skin
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Passive neck flex hips & knees flex
Purpura
Petechiae/splinter hem, pustular lesionsmicroemboli
Fundi
Neuro Exam
Diagnosis
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Parenchymal
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CT is the imaging of choice
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Brain abscess, encephalitis, toxoplasmosis
Meningeal
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Lumbar puncture
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Neoplasm, CNS vasculitis, SAH
Diagnosis
Parameter (normal)
Bacterial
Viral
Neoplastic
Fungal
OP (<170 mm CSF)
>300mm
200mm
200
300mm
WBC
(<5mononuclear)
>1000
<1000
<500
<500
%PMN’s (0)
>80%
1-50%
1-50%
1-50%
Glucose
(>40mg/dL)
<40
>40
<40
<40
Protein (<50mg/dL)
>200
<200
>200
>200
Gram stain (-)
+
_
-
_
Cytology (-)
_
_
+
+
Diagnosis
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An aseptic profile
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Must think about…
Partially treated bacterial infection
 Bacterial infections adjacent to the subarachnoid space
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Diagnosis
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Tests to order on the CSF
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Tube #1 cell count with diff
Tube #2 protein,glucose
Tube #4 cell count with diff, gram stain/culture
Tube #3
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Viral cultures
Borrelia (lyme disease)
India ink/cryptococcal antigen (immunocomp)
Acid fast stain/culture for mycobacteria (TB)
Latex agglutination for bacterial Antigens
PCR
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Herpes, arbovirus
Lumbar Puncture
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Contraindications
Infection in overlying skin
 Relative
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Coagulopathy
 Thrombocytopenia
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If delay is anticipated obtain blood cultures and
GIVE antibiotics
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You have 2 hours after ATB given before sensitivity is
effected
Lumbar Puncture
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Considerations for not obtaining CT before
performing LP
Age <60
 Immunocompetent
 No h/o CNS disease
 No recent seizure (<1week)
 Normal sensorium & cognitition
 No papilledema
 No focal neuro deficits
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Treatment
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First priority
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Second priority in some cases
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Antibiotics
Anti-inflammatories
Third priority
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Counter the adverse effects of increased ICP &
vasculopathy
Emperic Antibiotics
Age/Special
Gram Stain
Drug
18-50y/o
Negative
Ceftriaxone 2g IV
+
vanco 1g IV or rifampin
>50 y/o
Negative
Ceftriaxone
+
ampicillin
+
vanco or rifampin
Recent penetrating head
injury/ surgery/shunt
Negative
Vanco 25mg/kg then 19mg/kg using
Matzke nonogram
+
ceftazidime
immunocompromised
Negative-------------------------------------
GPC------------------------------------------
GNC-----------------------------------------
GPR------------------------------------------
GNR-----------------------------------------
Vanco+ amp+ ceftazidime
Ceftriaxone + vanco
Pen G
Amp + gent
Cetazidime + aminoglycoside
Emperic Antivirals
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Concern of herpes
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Acyclovir 10mg/kg IV Q 8 hours
Steroids
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Dexamethasone
10mg IV 15 minutes prior to antibiotics
 Shown to decrease M&M in S. pneumoniae but
NOT N. meningitidis
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N Engl J Med 2002; 347:1549-1556, Nov 14, 2002.
Complications
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Seizures
Hyponatremia
SIADH
CVA
Coagulopathies
Cognitive deficits, epilepsy, hydrocephalus,
hearing loss affect 25% of survivors
Chemoprophylaxis
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Household/school/daycare contacts last 7 days
Direct exposure to secretions
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Kissing, sharing utensils/toothbrushes, mouth to
mouth, intubation without a mask
First line: rifampin 10mg/kg (max dose 600mg)
Q12h x 4 doses
Alternative: ceftriaxone, cipro, sulfisoxazole
Viral Meningitis
Viral Menigitis
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85% secondary to
Echo Coxsackie
 Entero
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Also consider HSV, and EBV
Neutrophils may predominate in the CSF in the
first 24 hours
Consider starting ATB’s until cultures come
back (-)
Viral Encephalitis
Viral Encephalitis
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Infection of brain parenchyma
Presents of neurological abnormalities
distinguish it from meningitis
Epidemiology
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Incidence is 1/10 of bacterial meningitis
HSV-1, zoster, EBV,CMV, rabies, arbo
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Arbo
LAC (La Crosse)-diagnosed most frequently
 SEE(St Louis)-20% mortality in elderly
 WEE(Western)- causes seizures in 90% of infected
infants, permanent neuro deficits in 50%
 EEE(Eastern)- most devastating, mortality 70%
 WNV(West Nile)
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Pathophysiology
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Portals of entry
Arbo-transmitted by mosquitoes, ticks
 Rabies-bite by infected animal
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Hematogenous dissemination v. travel
backwards on axons (HSV,HZV,rabies)
Dysfunction & damage caused by disruption of
neural cell function & inflammation
Pathophysiology cont.
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Gray matter predominately affected
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Cognitive/psychiatric signs, lethargy, seizures
White matter affected in post-infectious
encephalomyelitis
Clinical features
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New psych symptoms
Cognitive deficit (aphasia, amnesia, confusion)
Seizure
Movement d/o
Diagnosis
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MRI-more sensitive than CT
CT
EEG
LP-findings consistent with aseptic meningitis
Differential
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Exclude the killers
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More meningeal symptoms
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Bacterial meningitis & SAH
Lyme, TB, fungal, bacterial, viral, neoplastic
More parenchymal symptoms
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Abscess, bacterial endocarditis, post-infectious
encephalomyelitis, toxic or metabolic
encephalopathy
Treatment
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HSV: acyclovir 10mg/kg IV
CMV: ganciclovir
Rabies/EEE/HSVdevastating & usually fatal
or residual deficits
Brain Abscess
Brain Abscess
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Focal pyogenic infection
Pus-filled cavity ringed by granulation tissue &
outer fibrous capsule surrounded by edematous
brain tissue
Epidemiology
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Paranasal sinus focus
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10-30 y/o
Otic
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Bimodal: <20 y/o & >40 y/o
Pathophysiology
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Hematogenous spread
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1/3 of cases
Contiguous (middle ear, sinus, teeth)
1/3 of cases
 Otogenic (Bacteroides)temporal lobe/cerebellum
 Sinogenic & odontogenic(anaerobic &
microaerophilic streptococci)frontal lobe
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Clinical Features
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Classic triad
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HA, fever, focal deficit
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<1/3 of cases
Toxic appearance is rare
 Seizures, vomiting, confusion, obtundation possible
 Frontal lobe-hemiparesis
 Temporal lobe- homonymous superior quadrant
visual field deficit or aphasia
 Cerebellum-limb incoordination or nystagmus
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Diagnosis
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CT with contrast
LP contraindicated
Biopsy or aspiration for confirmation
Treatment
Presumed Source
Primary Empiric Tx
Alternative Tx
Otogenic
Cefotaxime 2g IV q8h
Bactrim 5mg/kg IV q6h
+
Flagyl 1giv then 500mg q6 or
chloramphenicol
Sinogenic or
odontogenic
Pen 24 million units/d IV
divided q4h
+
Flagyl 1g IV then 500mg q6h
Pen (same dose)
+
Chloramphenicol 100mg/kg/d
divided q6h
Penetrating trauma or
neurosurgery
Nafcillin 2g IV q4h
+
Ceftazidime 2g IV q8h
Vanco 15mg/kg (max 1g)IV q6h
+
Ceftazidime 2g IV
Hematogenous
Pen 24 million units/d divided
q4h
+
Flagyl 1g then 500mg q6h
Pen (same dose)
+
Chloramphenicol 100mg/kg/d
divided q6h
No obvious source
Cefotaxime 2g IV q6h
+
Flagyl 1g IV then 500mg q6h
No recommendations
Questions
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1. CSF analysis returns with the following values:
glucose 20 WBC 1200 Protein 300. This profile is
consistent with
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A. Bacterial meningitis
B. viral meningitis
C. Fungal meningitis
2. Which of the following is an absolute
contraindication to performing an LP
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A. Coagulopathy
B. Infection of the overlying skin
C. thrombocytopenia
Questions
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3. T/F Steroids have been shown to decrease
morbidity & mortality in meningitis caused by Strep
pneumo
4. T/F Brain abscesses are confirmed by LP.
5. Which antibiotic regimen should be initiated in an
immunocompromised patient suspected of having
bacterial meningitis without any allergies
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A. Pen G
B. Ceftriaxone & vanco
C. Vanco, gent, & ceftazidime
Answers: 1. A
2. B
3. T
4. F
5. C