CNS Infections - Cleveland Clinic
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Transcript CNS Infections - Cleveland Clinic
CNS Infections
11-23-04
Chapter 235
Bacterial Meningitis
Epidemiology
400 per 100,000 in neonates
1-2 per 100,000 in adults
S pneumoniae & N meningitidis m/c
HIB vaccine has been very effective
Mortality
5% in children beyond infancy
25% in neonates and in adults
Pathophysiology
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
25% of adult cases “classic”
Rapid development of
Fever
HA
Stiff neck
Photophobia
Change in MS
Nonspecific signs/symptoms in very young/old
25% will develop seizures
Clinical Features
History
Living conditions
College dorm/barracksN meningitidis
Trauma
Recent neurosurgeryStaph/gram(-) rod
Immunocompetence
Immunization hx
NoneHiB
Antibiotic use
Clinical Feratures
Physical Exam
Brudzinski
Kernig
Flex hip, ext knee hamstrings contract
Skin
Passive neck flex hips & knees flex
Purpura
Petechiae/splinter hem, pustular lesionsmicroemboli
Fundi
Neuro Exam
Diagnosis
Parenchymal
CT is the imaging of choice
Brain abscess, encephalitis, toxoplasmosis
Meningeal
Lumbar puncture
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
An aseptic profile
Must think about…
Partially treated bacterial infection
Bacterial infections adjacent to the subarachnoid space
Diagnosis
Tests to order on the CSF
Tube #1 cell count with diff
Tube #2 protein,glucose
Tube #4 cell count with diff, gram stain/culture
Tube #3
Viral cultures
Borrelia (lyme disease)
India ink/cryptococcal antigen (immunocomp)
Acid fast stain/culture for mycobacteria (TB)
Latex agglutination for bacterial Antigens
PCR
Herpes, arbovirus
Lumbar Puncture
Contraindications
Infection in overlying skin
Relative
Coagulopathy
Thrombocytopenia
If delay is anticipated obtain blood cultures and
GIVE antibiotics
You have 2 hours after ATB given before sensitivity is
effected
Lumbar Puncture
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
Treatment
First priority
Second priority in some cases
Antibiotics
Anti-inflammatories
Third priority
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
Concern of herpes
Acyclovir 10mg/kg IV Q 8 hours
Steroids
Dexamethasone
10mg IV 15 minutes prior to antibiotics
Shown to decrease M&M in S. pneumoniae but
NOT N. meningitidis
N Engl J Med 2002; 347:1549-1556, Nov 14, 2002.
Complications
Seizures
Hyponatremia
SIADH
CVA
Coagulopathies
Cognitive deficits, epilepsy, hydrocephalus,
hearing loss affect 25% of survivors
Chemoprophylaxis
Household/school/daycare contacts last 7 days
Direct exposure to secretions
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
85% secondary to
Echo Coxsackie
Entero
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
Infection of brain parenchyma
Presents of neurological abnormalities
distinguish it from meningitis
Epidemiology
Incidence is 1/10 of bacterial meningitis
HSV-1, zoster, EBV,CMV, rabies, arbo
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)
Pathophysiology
Portals of entry
Arbo-transmitted by mosquitoes, ticks
Rabies-bite by infected animal
Hematogenous dissemination v. travel
backwards on axons (HSV,HZV,rabies)
Dysfunction & damage caused by disruption of
neural cell function & inflammation
Pathophysiology cont.
Gray matter predominately affected
Cognitive/psychiatric signs, lethargy, seizures
White matter affected in post-infectious
encephalomyelitis
Clinical features
New psych symptoms
Cognitive deficit (aphasia, amnesia, confusion)
Seizure
Movement d/o
Diagnosis
MRI-more sensitive than CT
CT
EEG
LP-findings consistent with aseptic meningitis
Differential
Exclude the killers
More meningeal symptoms
Bacterial meningitis & SAH
Lyme, TB, fungal, bacterial, viral, neoplastic
More parenchymal symptoms
Abscess, bacterial endocarditis, post-infectious
encephalomyelitis, toxic or metabolic
encephalopathy
Treatment
HSV: acyclovir 10mg/kg IV
CMV: ganciclovir
Rabies/EEE/HSVdevastating & usually fatal
or residual deficits
Brain Abscess
Brain Abscess
Focal pyogenic infection
Pus-filled cavity ringed by granulation tissue &
outer fibrous capsule surrounded by edematous
brain tissue
Epidemiology
Paranasal sinus focus
10-30 y/o
Otic
Bimodal: <20 y/o & >40 y/o
Pathophysiology
Hematogenous spread
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
Clinical Features
Classic triad
HA, fever, focal deficit
<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
Diagnosis
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
1. CSF analysis returns with the following values:
glucose 20 WBC 1200 Protein 300. This profile is
consistent with
A. Bacterial meningitis
B. viral meningitis
C. Fungal meningitis
2. Which of the following is an absolute
contraindication to performing an LP
A. Coagulopathy
B. Infection of the overlying skin
C. thrombocytopenia
Questions
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
A. Pen G
B. Ceftriaxone & vanco
C. Vanco, gent, & ceftazidime
Answers: 1. A
2. B
3. T
4. F
5. C