Meningitis and Lumbar Puncture

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Meningitis and Lumbar Puncture

• Jessica Kirk, MD
• July 26, 2007

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Overview

• Features of Bacterial Meningitis
• Features of Viral Meningitis
• Lumbar Puncture
• Indications/Contraindications
• Procedure
• Interpreting Results

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Bacterial Meningitis an overview

• Suspected bacterial meningitis is a medical
  emergency, and IMMEDIATE steps must taken to
  identify the specific cause.
• These steps include
• History
• Physical Exam
• Laboratory Data
• Imaging

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Bacterial Meningitis History

• The History should include, at a minimum, the
  following information
• Course of illness (progressive vs. acute and
  fulminant)
• Presence of symptoms c/w meningeal inflammation
• Presence of seizures
• Presence of predisposing factors (i.e. recent
  resp. or ear infection, penetrating head trauma,
  travel to endemic area, etc.)
• Immunization Hx
• Hx of drug allergies (may affect therapy)
• Recent use of antibiotics

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Bacterial Meningitis Physical Exam

• Important aspects of the physical exam are as
  follows
• Vital signs provide clues about volume status,
  presence of shock/increased ICP
• HC in children lt18mo
• Meningeal signs (chin to chest/ Kernig/
  Brudzinski)
• Neurologic exam
• Integumentary exam (petichiae and purpura most
  commonly assoc. with N. meningitidis)
• Signs of other bacterial infections (i.e.
  cellulitis, sinusitis, otitis media, etc.)

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Bacterial Meningitis Laboratory Data

• Blood Tests
• CBC with diff
• Blood culture
• Chem 8
• Coags if any petechiae or purpura noted
• CSF
• Cell Count
• Glucose and protein
• Gram stain
• Culture and sensitivity
• Other (meningococcal panel)

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Bacterial Meningitis Imaging

• CT scan may be performed to rule out an
  intracranial process that would contraindicate an
  LP, but does not exclude subsequent herniation.
• Indications for CT before LP
• Coma
• CSF shunt
• Hx of hydrocephalus
• Hx of trauma/neurosurgery
• Papilledema
• Focal neurologic deficit

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Bacterial Meningitis Diagnosis

• A HIGH LEVEL OF SUSPICION IS KEY TO DIAGNOSING
  MENINGITIS IN CHILDREN.
• Acute bacterial meningitis should be suspected in
  children with fever and signs of meningeal
  inflammation.
• In infants the signs may include fever,
  hypothermia, lethargy, resp. distress, jaundice,
  poor feeding, vomiting, diarrhea, seizures,
  restlessness, irritability, and/or bulging
  fontanel.
• No single clinical sign is pathognomonic.
• Either isolation of bacteria in CSF, OR isolation
  of bacteria in blood cultures in a patient with
  CSF pleocytosis confirms the diagnosis.

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Bacterial Meningitis Causative Organisms

• 1mo 2yr
• S. pneumoniae (penicillin resistance)
• N. meningitidis
• GBS
• 2yr 18yr
• N. meningitidis
• S. pneumoniae
• Hib

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Bacterial Meningitis Treatment

• Empiric treatment of meningitis should be started
  immediately after the LP is performed. You cannot
  delay treatment of there is a contraindication or
  inability to perform an LP. For example, if the
  LP is delayed due to a need for imaging, blood
  cultures should be obtained and antibiotics
  started before the imaging study.
• Empiric treatment consists of bactericidal
  antibiotics that have good CSF penetrance,
  usually a third-generation cephalosporin (eg
  cefotaxime, ceftriaxone) and vancomycin.
• If cephalosporins or Vanc are contraindicated in
  a patient, consult ID.

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Bacterial meningitis Treatment cont.

• Cefotaxime 200mg/kg/day or 50mg/kg/dose IV Q6hrs
• Ceftriaxone 100mg/kg/day or 50mg/kg/dose IV
  Q12hrs
• 75mg/kg loading dose
• Vancomycin 60mg/kg/day or 15mg/kg/dose IV Q6hrs

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Bacterial Meningitis Treatment cont.

• Duration of treatment is determined on a
  case-by-case basis with assistance from Peds ID.
  Contributing factors may include positive CSF cx,
  clinical course, causative pathogen, and response
  to therapy.

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Bacterial Meningitis Outcomes

• The mortality rate of untreated bacterial
  meningitis approaches 100.
• Meta-analysis has shown a mortality rate of 5
  in developed countries, depending on causative
  organism.
• The most common sequelae are neurologic, and
  occur in 15-25 of survivors
• Deafness
• Mental Retardation
• Spasticity/Paresis
• Seizures

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Bacterial Meningitis Follow-up

• Hearing Evaluation at or shortly after discharge
• Developmental surveillance

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Viral Meningitis an overview

• Viral, or aseptic, meningitis is the most common
  type of meningitis. It is defined as
• A febrile illness with clinical signs and
  symptoms of meningeal irritation
• No associated neurologic dysfunction
• No evidence of bacterial pathogens in the CSF (in
  a pt. who hasnt received antibiotics)

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Viral Meningitis Clinical Manifestations

• Common features include
• Acute onset of fever, headache, nausea, vomiting,
  stiff neck.
• Physical findings are generally limited,
  nonspecific, and not necessarily present. The
  most prevalent are
• Nuchal rigidity, bulging fontanel, and other
  signs of viruses such as rash, conjunctivitis,
  and pharyngitis.

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Viral Meningitis Laboratory Data

• CSF
• WBC
• Glucose
• Protein
• Enterovirus PCR
• HSV PCR

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Viral Meningitis Causative Organisms

• Enteroviruses
• Herpesviruses
• Arboviruses
• Influenza

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Viral Meningitis Treatment

• Herpes meningitis in children is treated with
  Acyclovir 30mg/kg/day, or 10mg/kg/dose IV Q8hrs,
  for a minimum of 14-21 days
• Neonatal dosing is 60mg/kg/day, or 20mg/kg/dose
  IV Q8hrs for 21 days.
• EV infections are treated symptomatically and
  rarely require hospitalization beyond the
  neonatal period.
• Treatment for EBV, Arbovirus, and Influenza
  meningitis is mainly supportive.

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Lumbar Puncture Indications

• Suspected CNS infection
• Suspected SAH
• Introducing chemotherapy or contrast
• Removal of CSF

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Lumbar Puncture Contraindications

• Absolute
• Increased ICP
• Relative
• Cardiopulmonary instability
• Soft tissue infection at puncture site
• Bleeding diathesis
• Active bleeding
• Platelet count lt50,000
• INR gt 1.4

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Lumbar Puncture Patient Counseling

• Your job is to provide a clear explanation of the
  urgent indications of the procedure, as well as
  the details of the procedure itself.
• In order to obtain informed consent, you must
  list both risks and benefits.

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Lumbar Puncture Patient Counseling cont.

• Risks
• Postspinal headache
• Epidermoid tumor
• Infection
• Cerebral herniation
• Spinal hematoma
• Benefits
• The benefit of early diagnosis far outweighs the
  risk of the procedure if there are no
  contraindications.

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Lumbar Puncture Anatomy

• In older children, LP can be performed from the
  L2-L3 interspace to the L5-S1 interspace. In
  children younger than 12mo, LP must be performed
  below the L2-L3 interspace.
• An imaginary line that connects the 2 PSIC
  intersects the spine at approximately L4.

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Lumbar Puncture Pre-procedure

• Local anesthesia can be provided with either
  lidocaine and/or EMLA.
• The patient must be well-positioned to see
  landmarks
• Hips and shoulders should be perpendicular to the
  exam table
• The gluteal crease should align with the spinous
  processes.
• Feel free to ask the nurse to reposition the
  patient.
• Watch for respiratory function throughout the
  entire procedure!

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Lumbar Puncture Procedure

• An LP is performed using universal precautions
  and sterile technique.
• Put on sterile gloves and clean the puncture site
  with betadyne. The area should be large,
  including the PSIS to use as a landmark.
• Place sterile drapes around the puncture site.
• If infiltrating with Lidocaine, do this now.

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Lumbar Puncture Procedure cont.

• Check your spinal needle- Is the stylet in place?
  Is it the appropriate diameter and length? Is it
  a spinal needle?
• Are your collection tubes upright and open?
• Find your landmark- you may want to mark it with
  your fingernail.
• Advance the spinal needle, bevel up, parallel to
  the exam table, with the tip of the needle
  advancing toward the patients umbilicus.

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Lumbar Puncture Procedure cont.

• Advance SLOWLY. In newborns, you may only get the
  bevel in before you are in the subarachnoid
  space.
• The stylet may be removed as the needle is
  advanced to look for CSF.
• Use of a manometer is optional at this time to
  measure opening pressure.
• Put 1cc, or about 15-20 drops in each of the 4
  tubes.
• Replace the stylet and remove the needle.
• DISPOSE OF YOUR SHARPS IMMEDIATELY.

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Lumbar Puncture Fluid Collection

• You should label your own CSF. The label must
  include the tube number and what test you want
  ordered, as well as your initials, time, and
  date.
• CSF 1 Gram stain and culture
• CSF 2 Glucose and protein
• CSF 3 Cell count
• CSF 4 Save (or Herpes PCR, EV PCR, mening.
  Panel, etc.)

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Lumbar Puncture Misc.

• Please be courteous and clean up your own mess.
  Dispose of all unused sharps before throwing away
  the kit.

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Lumbar Puncture Troubleshooting

• Bony resistance
• Increase flexion of patient, or
• Withdraw needle to soft tissue and re-palpate to
  make sure spine is not rotated.
• Poor flow
• Rotate needle by 90 degrees
• Replace stylet and advance slightly
• Pull needle back and redirect
• Remove needle and attempt different site
• You must use a new needle at this time.

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Lumbar Puncture Troubleshooting cont.

• Taumatic Tap
• Occurs when needle hits venous plexus
• CSF typically clears if in subarachnoid space
• Remove needle and reattempt with new needle if
  clot forms or fluid doesnt clear.

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Lumbar Puncture Interpreting Results Cont.
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Lumbar Puncture Interpreting Results cont.

• When a tap is bloody it may be a traumatic tap,
  or it could be blood in the CSF. Your CSF
  analysis will provide crenated and uncrenated
  RBCs. Crenated means the RBCs have started
  breaking down, and therefore have likely been in
  the CSF longer. This may be a sign that you are
  dealing with Herpes meningitis.

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Lumbar Puncture Interpreting Results

• Interpreting CSF can be subjective in many cases.
  Results will vary based on timing of the tap in
  the course of the illness, antibiotics given,
  other cultures obtained, and quality of the tap.
• You should use the resources available to you
  such as your teammates experience and Peds ID
  consult to help you decide on a course of action.

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Lumbar Puncture

• Demonstration of the LP kit

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Meningitis and Lumbar Puncture

• Questions?
• Sources will be available on website.