Meningitis and Lumbar Puncture

Jessica Kirk, MD

July 26, 2007

Overview

Features of Bacterial Meningitis Features of Viral Meningitis Lumbar Puncture:

Indications/ContraindicationsProcedureInterpreting Results

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

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

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 <18mo 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.)

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)

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

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.

Bacterial Meningitis: Causative Organisms 1mo – 2yr:

S. pneumoniae (*penicillin resistance)N. meningitidisGBS

2yr – 18yr:N. meningitidisS. pneumoniaeHib

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.

Bacterial meningitis: Treatment cont.

Cefotaxime 200mg/kg/day or 50mg/kg/dose IV Q6hrs

Ceftriaxone 100mg/kg/day or 50mg/kg/dose IV Q12hrs75mg/kg loading dose

Vancomycin 60mg/kg/day or 15mg/kg/dose IV Q6hrs

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.

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

Bacterial Meningitis: Follow-up

Hearing Evaluation: at or shortly after discharge

Developmental surveillance

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 irritationNo associated neurologic dysfunctionNo evidence of bacterial pathogens in

the CSF (in a pt. who hasn’t received antibiotics)

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.

Viral Meningitis: Laboratory Data

CSF: WBCGlucoseProteinEnterovirus PCRHSV PCR

Viral Meningitis: Causative Organisms

Enteroviruses Herpesviruses Arboviruses Influenza

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.

Lumbar Puncture: Indications

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

Lumbar Puncture: Contraindications Absolute:

Increased ICP Relative:

Cardiopulmonary instabilitySoft tissue infection at puncture siteBleeding diathesis:

• Active bleeding• Platelet count <50,000• INR > 1.4

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.

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.

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.

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!

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.

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 patient’s umbilicus.

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.

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.)

Lumbar Puncture: Misc.

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

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.

Lumbar Puncture: Troubleshooting cont.

Taumatic Tap:Occurs when needle hits venous

plexusCSF typically clears if in subarachnoid

spaceRemove needle and reattempt with

new needle if clot forms or fluid doesn’t clear.

Lumbar Puncture: Interpreting Results Cont.

Glucose Protein # of WBC’s

Organism present

Bacterial Meningitis

↓ ↑ >1000 ↑neutros

Gram stain CSF/bld cx

Viral Meningitis

Nl or slightly↓

Nl or slightly↑

~10-500 ↑lymphs

no

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 RBC’s. Crenated means the RBC’s 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.

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.

Lumbar Puncture

Demonstration of the LP kit

Meningitis and Lumbar Puncture

Questions?

Sources will be available on website.