Meningitis – CID 2004

Meningitis:

• Inflammation of the meninges surrounding the brain & spinal cord
• Peak age: 6-12 mo, 90% <5yr
• Common Organisms
  • 0-4wk: GBS, E Coli, Listeria monocytogenes, Klebsiella
  • 1-23mo: GBS, E Coli, S. Pneumo, N. Meningitidis, H. Influenzae
  • >2yr: S. Pneumo, N. Meningitidis, Listeria Monocytogenes (>50yo + comorbidities)
  • Viral: HSV1/2, VZV, enteroviruses, West Nile
  • Fungal: Cryptococcus, coccidiides
  • Other: Lyme dz, Neurosyphilis, TB

1  In the patient with a non-specific febrile illness, look for meningitis, especially in patients at higher risk (e.g., immuno-compromised individuals, alcoholism, recent neurosurgery, head injury, recent abdominal surgery, neonates, aboriginal groups, students living in residence).

Risk Factors:

• Lack of immunization against S. penumoniae & H. Influenzae type B
• hematogenous spread after invasion from a mucosal surface (nasopharynx)
• Parameningeal focus: Otitis media, infection, sinusitis
• Penetrating head trauma
• Anatomical meningeal defects – CSF leaks
• Prev Neurosurgical procedures, shunts
• Immunocompromise: corticosteroids, DM, prematurity, asplenia, HIV, hypogammaglobulinemia, complement deficiency
• Contact with colonized or infected persons – exposures at day care centres, recent travel, household contact

Clinical Features:

• Classic Triad: fever, neck stiffness, altered mental status (absence doesn’t r/o meningitis)
  • No fever, no neck stiffness, normal mental staus = 99% sensitivity
• Neonates / children:
  • Hx: Fever or hypothermia, vomiting, lethargy, irritability, poor feeding, diarrhea, respiratory distress, Sz
  • PE: Toxic, bulging anterior fontanelle, respiratory distress / apnea, petechial/purpuric rash, jaundice, omphalitis
• Older children / adults:
  • Hx: fever, H/A, neck/back pain/stiffness, confusion, n/v, lethargy, photophobia, altered LOC, confusion, Sz,irritability
  • PE: Toxic, ↓LOC, nuchal rigidity, Kernig’s / Bruzinski’s, focal neurological signs, papilledema, petechial/purpuric rash
• Meningococcal meningitis: petechial rash on lower extremities
• Signs of Meningismus – BONK
  • Brudzinski’s – flexion of neck = involuntary flexion of the knee + hip
  • Opisthotonos – rigid spasm of the body w/ the back fully arched & heels / head bent back
  • Nuchal rigidity
  • Kernig’s = pain with passive extension of a flexed knee
  • Jolt accentuation (sen 97% spec 60%) = turn head horizontally at 2-3/sec; + = ↑ h/a
• Neuroexam: papilledema, sz, focal deficit

2  When meningitis is suspected ensure a timely lumbar puncture.

Ix:

• B/W: CBCD, electrolytes (SIADH), blood C & S
• LP: LP w/o CT in pt
  • w/o altered LOC,
  • no recent Sz, no Hx of CNS dz,
  • not immunocompromised,
  • <60yr
• CSF: cloudy in bacterial meningitis
  • opening pressure
  • cell (WBC & RBC) count + differential
  • glucose, protei concentration
  • gram stain, bacterial C&S
• AFB, fungal C&S, cryptococcal antigen in
  • immunocompromised pt,
  • subacute illness,
  • suggestive travel hx or TB exposure
• PCR for HSV, VZV, EBV, enteroviruses if viral cause suspected
• U/A & U C&S in infants, Gram stain + Cx of petechial / purpuric lesions
• CT, MRI, EEG if focal neurological signs present

3  In the differentiation between viral and bacterial meningitis, adjust the interpretation of the data in light of recent antibiotic use.

CSF profiles

1. Bacterial meningitis
   • ↓ glucose (<30), ↑↑ protein (>100), WBC 500-10,000/ul – predominant Neutrophils >50%
2. Viral Meningitis
   • Normal glucose, ↑ protein (50-100), WBC 10-500/ul – predominant Lymphocytes (herpes WBC 10-1000)

4  For suspected bacterial meningitis, initiate urgent empiric IV antibiotic therapy (i.e., even before investigations are complete).

Bacterial meningitis is a medical emergency – don’t delay Abx before CT or LP

• Isolation with appropriate infection control until 24 hr after Cx-sensitive abx therapy
• Fluid restrict if any concern for SIADH
• hearing test after
• Report to public health

Empiric Tx:

• <1mo: ampicillin + cefotaxime ± gentamicin IV
• >1mo: Vancomycin + ceftriaxone IV
  • Add ampicillin IV (or TMP-SMX) if risk factors for Listeria monocytogenes present
    1. >50yo,
    2. alcoholism,
    3. immunocompromised
• Acyclovir for HSV meningitis
• Dexamethasone IV within 20minpriortoorwithfirst dose of Abx if >6 weeks
  • ? benefit on prevention of hearing loss

Prognosis

C/I:

• H/A, Sz, cerebral edema,
• hydrocephalus, SIADH,
• residual neurological deficit (especially CN VIII),
• deafness, death

Mortality:

• S. Pneumoniae 25%, N. Meningitidis 5-10%, H. influenzae 5%
• Worse prognosis if
  • extremes of age,
  • delays in dx and tx
  • stupor or coma, Sz, focal neurological signs, septic shock at presentation

5  Contact public health to ensure appropriate prophylaxis for family, friends and other contacts of each person with meningitis.

Prophylaxis: close or household contacts

1. H. Influenzae – Tx with Rifampin if they live with an inadequately immunized or immunocompromised child <4yr
2. N. Meningitidis – Ciprofloxacin, rifampin, or ceftriaxone

Prevention – Immunization

• Children: Immunization against H. influenze (Pentacel), S penumoniae (Synflorix, Prevnar-13), N. Meningitidis (Menjugate / Menactra)
• Adult: Immunization against N. Meningitidis in selected circumstances: Outbreaks, travel, epidemics & S. Pneumoniae (pneumovax) for high-risk groups

Public healthy Agency of Canada Indications:

1. Pneumococcal polysaccharide vaccine (Pneumovax)
   • >65
   • <2 with chronic cardio/respiratory/hepatic/renal disorders, asplenia, sickle cell or immunosuppression
2. Meningococcal C-conjugate vaccine (Menjugate)
   • young adults (not immunized in childhood)
   • Asplenia – Quadraveltn vaccine (Menactra / Menomune) preferred
   • Travellers to high-risk areas – Quadraveltn vaccine (Menactra / Menomune) preferred
   • Military recruits – Quadraveltn vaccine (Menactra / Menomune) preferred
   • Complement, factor D, or properdin deficiency- Quadraveltn vaccine (Menactra / Menomune) preferred

References:

• TN2014
• http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/Bacterial%20Meningitis%281%29.pdf