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CNS Infections
Sarah McPherson
Aug. 15, 2002
14 yo male presents with headache ane fever X 24 hrs.
Previously well. Seen in doctor’s office and sent to ED
after a witnessed focal seizure involving the right arm.
Other history unremarkable
O/E: Hr 100, BP 110/70, Temp 39.5
normal mental status, no nuchal rigidity
normal neuro exam
What would you do????
Clinical presentation of
meningitis
 Classic triad of bacteral meningitis (< 2/3 of presentations):
fever, nuchal rigidity, altered mental status
 also present as headaches, seizures (focal or
generalized, weight loss, night sweats, septic shock
 physical exam:
Kernig’s (unable to extend knee when pateint suline with hip
flexed)
Brudinski’s (flex neck and the hips also flex OR flex hip on one
side and see similar movement of the other hip)
Causes of meningitis
 Infectious
 Infectious
Bacterial:
fungal:
cryptococcus
coccidioides
candida
blastomyces
Parasites:
S. pneumo
N meningitidis
L monocytogenes
H flu
S. aureus
E coli
GBS
Viral:
HSV
enterovirus
HIV
varicella
toxopasma
Rickettsia:
Rocky Mountain spotted fever
Causes of meningitis
Drugs
NSAID
trimethoprim
isoniazid
Systemic disease
Serum sickness
vasculitis
SLE
sarcoidosis
Diagnosis
The LP:
Cell count: < 5 WBC, < 1 PMN
gram stain: no organism
xanthochromia: none
CSF-serum glucose: 0.6:1
protein: 15-45 mg/dl
Diagnosis
When should you CT before LP???
Profoundly altered mental status
papilledema
focal neuro deficit
minimal or absent fever
recent head trauma
recent onset seizure
Diagnosis
What if you have a VP shunt???
Infection rates 2.6-10% mostly in first few
months after insertion
mostly infected by skin flora (S aureus, coag
- staph, propionobacterium)
needle aspirate the reservoir (~25% better
than LP at identifying pathogen)
Back to the Case...
CT head normal
LP:
40 WBC
3 PMN
3 RBC
CSF glucose low (normal serum glucose)
protein elevated
negative gram stain
What now???
Definitive therapy
Bacterial Meningitis:
3rd generation cephalosporin
add Vanco if in area where drug resistant S.
pneumo is prevelant
add ampicillin to cover Listeria (< 3 months,
> 50 years)
Definitive therapy
What if your gram stain shows gramnegative coccobacilli???
The controversy of pre-treatment with
steroids...
Steroids...
 Shown to decrease neurologic and audiologic sequelae
in children > 2 months of age with H. flu infections
 benefit to adult patients or infections other than H. flu is
less clear
Recommendation:
treat children with gram
negative coccobacilli on gram stain with 0.15 mg/kg of
Dexamethasone just before giving antibiotics and then
q6h X 4 days
Another Case
22 yo girl presents with purpuric rash,
nuchal rigidity, temp 39.1, HR 110, BP
95/60, with altered mental status
How would this presentation alter your
approach?
ABC’s first, blood cultures, Antibiotics then
LP
Aseptic meningitis
Typically present as fever and nuchal
rigidity, may have headache, N&V
CSF may show increased WBC with
increased lymphocytes; normal to slightly
elevated protein; normal gram stain
Aseptic meningitis
Management:
supportive
relief of headache, fever, and dehydration
medical
if WBC on gram stain most clinicans will start on
empiric antibiotics pending C&S
if evidence of primary HSV infection, acyclovir
(oral 200 5X/day for 10 days)
70 yo man presents with fever 38.5 X 6
hr, headache, altered LOC and aphasia,
HR 85, BP 105/80
CT shows edema of the right temporal
lobe
LP 30 WBC, increased protein, normal
gram stain
Viral encephalitits
 Rare
 typically present with fever, headache, altered LOC,
behavioral or speech disturbnce, focal neuro deficits,
seizures
 CSF: mononuclear cell pleocytosis; elevated protein;
normal gram stain; PCR for HSV, CMV, HHV-6,
enterovirus (99% sens and 94% spec for HSV)
 CT, MRI, EEG may be helpful
Herpes Encephalitis
 Neonatal
CNS involvement in majority infants with herpetic disease in the
newborn period
CSF PCR is the gold standard
treatment : Acyclovir 30mh/kg/d divided q8h
with antiviral decreased mortality from 50% to 15% (pts with
CNS involvement)
2/3 will have long term neurologic sequelae despite treatment
Herpes Encephalitits
 HSE
most common cause of focal encephalitis
50% are > 50 yoa
without antiviral mortality > 80%
Treatment: Acyclovir 10 mg/kg q8h
Prognosis:
 if GCS < 6 outcome is poor
 if treatment is started in < 4 days from onset of symptoms
survival increases from 72 to 92%
with acyclovir 30% normal or minimal neuro impairment, 9%
moderate, 53% dead or severe impairment
West Nile Virus
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First isolated in 1937 in Uganda
first isolated in the Us in 1999
now found in Ontario, Quebec, Manitoba and possibly SK
transmitted by mosquito
in an area hwere West Nile is circulating ~ 1% of mosquitos will
carry it and there is an ~1% risk of infection after bite from a +
mosquito
symptoms: fever, headache, myalgia, arthralgia, lymphadenopathy,
maculopapular or roseloar rash on trunk or extremitites, nuchal
rigidity, seizure, altered LOC, muscle weakness
increased fatality in elderly pop’n
treatment supportive
of hospitalized patients mortality ranges from 3-15%
45 yo man with HIV presents with
headache and fever
neuro exam normal, temp 38.2, normal vitals
What next????
Normal CT head but when infused shows
ring enhancing lesion
DX? Toxoplasmosis
Rx? Admission, pyrimethamine 200 mg
po then 50 -100 mg qd plus clindamycin
900 iv q6h
CNS infection in the HIV
patient
 CNS infection occurs in 75-90% of patients with AIDS
 infections are the predominant cause of new neuro
symptoms/signs
toxoplasma gondii:
 most common cause of focal encephalitits
 DX: contrast enhanced CT or MRI showing ringed lesion; LP for Ab
to toxo Ag
 Rx: pyrimethamine + clinda or sulfadiazine
CNS infection in the HIV
patient
Cryptococcus neoformans
 causes focal lesion or diffuse encephalitits
 Dx: India ink stain, fungal culture,cryptococcal Ag in CSF
 Rx: Ampho B iv
HSV
M. tuberuculosis
Nocardia
all the bacteria that nonimmunosuppressed
patients have
new neuro symptoms/signs
+/- fever
Enhanced CT head
LP for all the normal stuff + India ink
stain, fungal culture, viral PCR’s, Toxo Ab,
Crypto Ag, Acid fast stain
25 yo women presents with back pain X 2
days. She has no other concerns. O/E
afebrile, hemodynamically stable, normal
neuro exam, you notice track marks on
her arms. She admits to ongoing IVDU.
What would you do next? What are your
concerns?
Epidural Abscess
 Risk factors:
IVDU
recent spinal or epidural anaesthesia
systemic infection
 Clinical features:
back pain
focal neuro deficits
fever (83% of the time)
 all IVDUers with back pain should be considered
infectious until proven otherwise (osteo vs epidural
abscess)
Epidural Abscess
Dx: CT, if negative and clinical suspicion
is high then need an MRI
Rx:
emergent surgical debridement
3rd generation cephalosporin + Flagyl