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Source: Mitropoulos IF, Hermsen ED, Rotschafer JC. Central Nervous System Infections. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. Accessed June 20, 2012.

  • Spinal meningitis
  • Central nervous system (CNS) infection

  • Infections within the CNS resulting from:
    • Hematogenous spread from primary infection site
    • Seeding from parameningeal focus
    • Reactivation from latent site
    • Trauma
    • Congenital defects in CNS

  • Most common causes: Streptococcus pneumoniae, Neisseria meningitidis, Listeria monocytogenes, and Haemophilus influenzae
  • Availability of pneumococcal and H. influenzae vaccines has resulted in decreased incidence.

  • Critical first step: nasopharyngeal colonization of host by bacterial pathogen.
    • Bacteria first attach themselves to nasopharyngeal epithelial cells, then are phagocytized into host’s bloodstream.
    • CNS bacterial pathogens have extensive polysaccharide capsule resistant to neutrophil phagocytosis and complement opsonization.
  • Neurologic sequelae of meningitis occur due to activation of host inflammatory pathways.
    • Bacterial cell wall components released, causing capillary endothelial cells and CNS macrophages to release cytokines.
    • Blood–brain barrier altered by proteolytic products and toxic oxygen radicals.
    • Coagulation cascade activated by platelet-activating factor.
    • Vasodilation stimulated by arachidonic acid metabolites.
  • Lead to:
    • Cerebral edema
    • Elevated intracranial pressure
    • Cerebrospinal fluid (CSF) pleocytosis
    • Decreased cerebral blood flow
    • Cerebral ischemia
    • Death

  • Neurologic sequelae frequently seen include:
    • Seizures
    • Sensorineural hearing loss
    • Hydrocephalus
  • Risk for development of sequelae depends on infecting organism; highest risk associated with pneumococcal meningitis.

  • Passive and active exposure to cigarette smoke
  • Presence of cochlear implant that includes positioner

  • Changes in CSF can be used as diagnostic markers of infection (Table 1).
  • Varies with age
    • Clinical picture more atypical and less pronounced in younger patients

Table 1. Mean Values of Components of Normal and Abnormal Cerebrospinal Fluid

Signs and Symptoms

  • Classic signs and symptoms
    • Fever
    • Nuchal rigidity
    • Altered mental status
    • Chills
    • Vomiting
    • Photophobia
    • Severe headache
    • Kernig and Brudzinski signs: poorly sensitive and frequently absent in children
  • Additional pediatric signs and symptoms
    • Bulging fontanelle
    • Apneas
    • Purpuric rash
    • Seizures more common in children (20–30%) than in adults (0–12%)

Means of Confirmation and Diagnosis

  • Gram stain and culture of CSF performed before antibiotic therapy initiated can confirm diagnosis of bacterial meningitis in 75–90% of cases.

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