CNS Infections

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CNS Infections

• Sarah McPherson
• Aug. 15, 2002

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• 14 yo male presents with headache ane fever X 24
  hrs. Previously well. Seen in doctors 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????

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Clinical presentation of meningitis

• Classic triad of bacteral meningitis (lt 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
• Kernigs (unable to extend knee when pateint
  suline with hip flexed)
• Brudinskis (flex neck and the hips also flex OR
  flex hip on one side and see similar movement of
  the other hip)

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Causes of meningitis

• Infectious
• Bacterial
• S. pneumo
• N meningitidis
• L monocytogenes
• H flu
• S. aureus
• E coli
• GBS
• Viral
• HSV
• enterovirus
• HIV
• varicella

• Infectious
• fungal
• cryptococcus
• coccidioides
• candida
• blastomyces
• Parasites
• toxopasma
• Rickettsia
• Rocky Mountain spotted fever

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Causes of meningitis

• Drugs
• NSAID
• trimethoprim
• isoniazid

• Systemic disease
• Serum sickness
• vasculitis
• SLE
• sarcoidosis

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Diagnosis

• The LP
• Cell count lt 5 WBC, lt 1 PMN
• gram stain no organism
• xanthochromia none
• CSF-serum glucose 0.61
• protein 15-45 mg/dl

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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

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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)

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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???

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Definitive therapy

• Bacterial Meningitis
• 3rd generation cephalosporin
• add Vanco if in area where drug resistant S.
  pneumo is prevelant
• add ampicillin to cover Listeria (lt 3 months, gt
  50 years)

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Definitive therapy

• What if your gram stain shows gram-negative
  coccobacilli???
• The controversy of pre-treatment with steroids...

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Steroids...

• Shown to decrease neurologic and audiologic
  sequelae in children gt 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

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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?
• ABCs first, blood cultures, Antibiotics then LP

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Aseptic meningitis

• Typically present as fever and nuchal rigidity,
  may have headache, NV
• CSF may show increased WBC with increased
  lymphocytes normal to slightly elevated protein
  normal gram stain

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Aseptic meningitis

• Management
• supportive
• relief of headache, fever, and dehydration
• medical
• if WBC on gram stain most clinicans will start on
  empiric antibiotics pending CS
• if evidence of primary HSV infection, acyclovir
  (oral 200 5X/day for 10 days)

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• 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

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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

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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

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Herpes Encephalitits

• HSE
• most common cause of focal encephalitis
• 50 are gt 50 yoa
• without antiviral mortality gt 80
• Treatment Acyclovir 10 mg/kg q8h
• Prognosis
• if GCS lt 6 outcome is poor
• if treatment is started in lt 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

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West Nile Virus

• 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 popn
• treatment supportive
• of hospitalized patients mortality ranges from
  3-15

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• 45 yo man with HIV presents with headache and
  fever
• neuro exam normal, temp 38.2, normal vitals
• What next????

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• 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

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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

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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

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The HIV patient with any new neuro symptoms/signs
/- fever

• Enhanced CT head
• LP for all the normal stuff India ink stain,
  fungal culture, viral PCRs, Toxo Ab, Crypto Ag,
  Acid fast stain

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• 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?

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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)

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Epidural Abscess

• Dx CT, if negative and clinical suspicion is
  high then need an MRI
• Rx
• emergent surgical debridement
• 3rd generation cephalosporin Flagyl