CNS Infections

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CNS Infections

• J. Ned Pruitt II
• Associate Professor of Neurology
• Medical College of Georgia

2
Case 1

• A 35 yo man is brought to the ER after 5 days of
  fever and chills. His wife relates that he has
  been very confused today and she called 911 after
  a seizure.
• PMHx is unremarkable except for a splenectomy at
  age 14 after a traumatic injury.
• Meds prn tylenol in the last week.
• NKDA
• Vaccinations are up to date.

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Case 1

• Exam Ill appearing man. Temp 39 C. Lethargic
  and can answer simple questions but can give no
  meaningful history. Neck is stiff to flexion and
  extension. A fine petechial rash is on his chest
  and upper arms.

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Case 1 What next?

• More examination or history?
• Labs?
• Radiology?
• Medications?

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CNS Infections

• Meningitis
• Bacterial, viral, fungal, chemical, carcinomatous
• Encephalitis
• Bacterial, viral
• Meningoencephalitis
• Abscess
• Parenchymal, subdural, epidural

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CNS Infections

• Signs and symptoms
• Fever
• Headache
• Altered mental status -lethargy to coma
• Neck stiffness meningismus flex/ext
• Increased intracranial pressure papilledema,
  nausea/vomiting, abducens palsies, bulging
  fontanelle in infants

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Exam in suspected CNS Infection

• Mental Status
• Cranial nerve and fundiscopic exam
• Meningeal Signs
• General exam rashes, lymphadenpathy
• Labs CBCD, BMP, PT/PTT, bHCG, blood cultures,
  UA CS
• Radiology CT head - uncontrasted if no focal
  signs, contrast if mass suspected

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LP

• Increased intracranial pressure is expected but
  LP contraindicated if a mass is present or if
  epidural spinal abscess is suspected
• Left lateral decubitus position
• L3-L4 interspace or L4-L5 interspace
• Think about your studies before the LP

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LP

• Tube 1 glucose and protein
• Tube 2 cell count and differential
• Tube 3 gram stain and rountine culture,
  cyrptococcal antigen, AFB stain and culture
• Tube 4 VDRL, or viral studies (PCR)

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CSF Characteristics
Bacterial Viral Fungal TB
Opening Pressure Elevated Slightly elevated Normal or High Ususally high
Glc Low Normal Low Low
Pro Very high Normal High High
Rbcs Few None None None
Wbcs (c/mm3) gt200 lt200 lt50 20-30
Diff PMNs Mono Mono Mono

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Key CSF Features

• CSF is not liquid gold get enough to get your
  answer
• CSF Glucose is 2/3 of serum glucose
• Important in diabetic patients
• Traumatic LPs
• CSF pro increases by 1 for every 1000 rbcs
• Tube 1 and Tube4 for rbcs when SAH is in the
  differential not as a routine
• Very high CSF Protein levels will make CSF yellow
• Send a full tube of CSF for cytology not just a
  few ccs

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Case 1

• CT of head negative.
• LP - OP (opening pressure) 250mm, glucose 17,
  protein 92, Rbcs 3, Wbcs 280 with 89 pmns, 11
  lymphocytes
• Gram stain - for Gram neg organisms

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Bacterial Meningitis

• Streptococcus pneumoniae
• Hemophilus influenzae
• Listeria moncytogenes
• Group B streptococcus
• Niesseria meningitidis

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Bacterial Menigitis

• Age less than 3 months-
• Group B strep
• L. Monocytogenes
• E. coli
• Strep pneumoniae

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Bacterial Meningitis

• 3 Months to 18 years
• N. meningitidis
• S. pneumoniae
• H. influenzae

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Bacterial Meningitis

• Age 18 to 50 years
• S. pneumoniae
• N. meningitidis
• H. influenzae

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Bacterial Meningitis

• Over age 50 years
• S. pnemoniae
• L. monocytogenes
• Gram (-) bacilli

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Treatment of Bacterial Meningitis

• PCN G or 3rd generation cephalosporin and consult
  ID
• Steroids Dexamethasone IV q6 for 4 days

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Viral Meningitis

• Very common
• Often caused by enteroviruses
• Treatment is supportive

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Viral Encephalitis

• Encephalitis (Meningoencephalitis)
• Altered mental status and seizures
• Herpes Simplex virus medial temporal lobe
• Acyclovir
• Management of seizures
• Very high morbidity and mortality
• PCR diagnosis of CSF
• West Nile, St Lousi E, EEE, CMV

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Chronic Meningitis

• Immunocompromised patients
• Cryptococcus neoformans
• HIV
• M. tuberculosis
• M. avium
• Carcinomatous meningitis
• Lung, breast

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Case 1

• Meningitis caused by N. Meningitidis
• Treatment with 3rd generation cephalosporin for
  10 days
• Dexamethasone
• Prophlaxis with Rifampin for contacts