Neurosurgery notes/Infection/Cranial infection/Meningitis

Meningitis

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Cranial infection
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Febrile seizures

General

Community acquire meningitis

  • Is more fulminant than meningitis following neurosurgical procedures
  • Due to community ones have more virulent microorganism and impaired host defences
  • Mechanisms
    • The subarachnoid space near the blood vessels fills first with neutrophils and fibrin → macrophages come → Subarach space fibrosis → arteritis, phlebitis, superior sagittal sinus thrombosis → hydrocephalus
  • Signs
      • Kernig sign
        • Knee extension is painful
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      • BrudziNsKi sign
        • Neck flexion leads to Knee flexion
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  • Organism
    • By fq- all three normally colonizes the nasopharynx
      • Haemophilus influenza
        • Mortality: 10%
      • Streptococcus pneumoniae
        • Mortality: 25%
        • Causes (MOPS)
          • Meningitis
          • Otitis media (in children)
          • Pneumonia
          • Sinusitis
      • Neisseria meningitidis
        • Mortality: 10%
      • Listeria
        • Acquired by ingestion of unpasteurized dairy products and cold deli meats,
        • Transmission from mom to baby
          • Transplacental
          • Vaginal during birth
    • Viral causes
      • Enteroviruses (especially coxsackievirus),
        • Most common virus
      • HSV-2 (HSV-1 = encephalitis),
      • HIV
        • Cryptococcus spp
      • West Nile virus (also causes encephalitis),
      • VZV
  • By age group
      • Intrauterine
      • Citrobacter koseri
          • Almost exclusively affects neonates and young infants.
          • Clinical features
            • Meningitis (accounts for 1% of neonatal meningitis)
            • Ventriculitis
            • 70-80% develop brain abscesses
              • High mortality (30%) and morbidity.
              • Highest risk of associated brain abscess
          • Intravenous antibiotics the mainstay of treatment
          • Surgical
            • Indications
              • Accessible cerebral abscesses
              • Ventriculitis evolving with acute hydrocephalus,
              • Symptomatic post-meningitis subdural effusions.
            • Surgical drainage is probably desirable but is not mandatory in every case.
            • Abscesses are often multiple or inaccessible, making a surgical approach impractical
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      Neonate (0-1 months)
      • Organism
        • Group B streptococci
          • Acute onset <5 days postpartum
          • With sepsis and pneumonia.
          • Intrapartum infection and has a 15–30% mortality
          • Screen
            • Pregnant women at 35–37 weeks of gestation with rectal and vaginal swabs.
            • Patients with ⊕ culture receive intrapartum penicillin prophylaxis
        • E. coli
          • Especially with the K1 capsular antigen
        • Listeria
      • Mortality: 50%
      • 50% survivors having permanent sequalae
        • Hydrocephalus
        • Encephalomalacia at the border zones, and in the white matter,
        • Seizures
        • Deafness
        • Mental retardation
        • Focal deficits
      • Risk increases with
        • Prematurity,
        • Prolonged membrane rupture,
        • Traumatic delivery,
        • Congenital malformations (myelomeningocele or dermal sinus), and
        • Acquired respiratory, GI, and umbilical infections
      1 to 3 months
      • S. pneumoniae
        • Associated with bilateral subdural effusions
          • Culture negative because they are due to increased permeability of blood vessels
      3 months to 3 yrs
      • H influenzae type b
        • Rarely occurs after 5 yrs
        • Nasopharyngeal colonization → sepsis → meningitis
        • Blood cultures 70% +
        • Need factor V and X to grow
        • Clinical features
          • Associated with bilateral subdural effusions
            • Culture negative because they are due to increased permeability of blood vessels
          • Seizures
        • Treatment
          • 3rd gen cephalosporin
          • Steroids use dec. incidences of deafness in children
      • S pneumoniae
      • N meningitidis
      • Enteroviruses
      Children to young adults
      • N meningitidis (#1 in teens)
        • Gram-negative intracellular diplococcus
        • Nasopharyngeal colonization → haematological spread → meningitis
        • Risk increases with
          • Decreased complement
          • SLE
        • Associated with cutaneous eruptions (60%), arteritis, and cardiac deaths.
        • Waterhouse-friderichsen syndrome
          • 10-20% kids (<10yrs) w/ meningitis
          • Large petechia haemorrhages, septic shock, fever, adrenal failure (haemorrhage into glands), DIC.
        • Treatment
          • Penicillin
          • Chloramphenicol
      • S pneumoniae
      • Enteroviruses
      • HSV
      Elderly
      • S pneumoniae
        • Elderly (because of age-dependent immune decline) and alcoholics (ethanol induces a chemotaxis defect and impairs phagocytosis)
        • Risk is increased with
          • Trauma (it is the normal flora of the mastoid, ear, sinus, and nose)
          • Infection
          • Sickle cell disease (caused by impaired splenic filtering, the risk is not increased in adults).
        • Detection uses the Quellung reaction
            • Because it has capsule
            A close-up of several white circles AI-generated content may be incorrect.
        • Treatment
          • Penicillin
      • Gram ⊝ rods
      • Listeria

Post-neurosurgical procedure meningitis

  • Organism: S aureus, enteroacteriaceae pseudomonas, pneumococci
  • Treatment: Vancomycin (MRSA cover) + ceftazidine
    • For pseudomonas add gentamicin
    • Swap Vancomycin out to nafcillin if no MRSA

Post craniopsinal trauma meningitis

  • Number
    • 10% with moderate-severe head injury
    • Most occurs within 2 weeks
    • 75% have base of skull #, 60% w/ CSF rhinorrhea
  • Pathogens
    • Gram post cocci: staph hemoliticus, S, epidermidis, Strep Pneumonia
    • Gram neg bacilli: E. Coli, Klebsiella, acinetobacter)
  • Treatment
    • CSF fistula to be managed with LP, head up or surgical closure
    • Antibiotics
      • Check local guidelines

Recurrent meningitis

  • Check for dermal sinus, CSF fistula, neurenteric cyst

Treatment

  • Bacterial meningitis
    • Rationale for the use of steroids in bacterial meningitis?
      • Experimental data have shown that an inflammatory response in the subarachnoid space contributes significantly to morbidity and mortality. Dexamethasone given before or with the first dose of antibiotics and then every 6 hours for 4 days improves outcome. There are no data to support steroids in patients who have meningitis related to CSF shunts and postneurosurgical procedures.
    • Antibiotics for intrathecal and intraventricular use.
      • They include vancomycin with doses of 10 to 20 mg/day for a few days until the cultures become negative,
      • Gentamicin and tobramycin with doses of 5 to 10 mg/day,
      • Amikacin 10 to 20 mg/day.
      • Preservative-free formulations should be used for intraventricular administration.
      • No antimicrobial agent has been approved by the Food and Drug Administration for intraventricular use.

CSF findings in different infectious meningitis

Infectious agent
Opening pressure (mm H₂O)
Glucose (mg/dL)
Protein (mg/dL)
White blood cell (Type)
Bacteria
High (< 200)
Low (< 40)
High (> 100)
Elevated (Neutrophilic)
Viral/aseptic
Normal/mildly elevated (< 200)
Normal (50–70)
Normal/mildly elevated (15–40)
Elevated (Lymphocytic)
Tuberculosis
Normal/mildly elevated (180–300)
Very low (< 40)
High (> 100)
Elevated (Pleocytosis)
Fungal
Normal/mildly elevated (180–300)
Low (< 40)
Mildly elevated (50–200)
Elevated (Lymphocytic)