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. http://accesspharmacy.com/content.aspx?aid=8001324.
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
- 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
- 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
- Neurologic sequelae frequently seen include:
- Sensorineural hearing loss
- 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
- 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 |Favorite Table|Download (.pdf)
Table 1. Mean Values of Components of Normal and Abnormal Cerebrospinal Fluid
|Differential (%)||>90a||≥80 PMNs||50b,c||>50b||>80b,c|
|Glucose (mg/dL)||50–66% simultaneous serum value||<40 (<60% simultaneous serum value)||<30–70||<30–70||<30–70|
- Classic signs and symptoms
- Nuchal rigidity
- Altered mental status
- Severe headache
- Kernig and Brudzinski signs: poorly sensitive and frequently
absent in children
- Additional pediatric signs and symptoms
- Purpuric rash
- Seizures more common in children (20–30%)
than in adults (0–12%)
Means of Confirmation
- Gram stain and culture of CSF performed before antibiotic
therapy initiated can confirm diagnosis of bacterial meningitis
in 75–90% of cases.