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Unformatted text preview: Learning Issue: Bacterial Meningitis Definition ● inflammation of the membranes that surround the brain and the spinal cord, ie the arachnoid and pia mater and the interposed CSF secondary to a bacterial infection that generally evokes a polymorphonuclear response in the CSF ● the inflammatory process extends throughout the subarachnoid space around the brain, the spinal cord, and the ventricles ● has high morbidity and mortality ● can occur at any age and in previously health individuals ● People with increased risk: immunosuppressed patients, pediatric patients, geriatric patients, males, low socioeconomic status, people living in crowded places (dormitories, military recruits) Etiology ● Specific pathogens: Strep pneumonia , Neisseria meningitides , Group B strep, Listeria monocytogenes , H. influenzae (used to be much more prevalent, 50% of cases, before vaccination was introduced; >70% of cases in children <5 years) ● Bacteria reach the subarachnoid space by a hematogenous route ● once pathogens enter the subarachnoid space, an intense host inflammatory response is triggered by lipoteichoic acid and other bacterial cell wall products produced as a result of bacterial lysis ● response is mediated by the stimulation of macrophage-equivalent brain cells that produce cytokines and other inflammatory mediators ● all of these responses result in damage in the subarachnoid space, leading to neuronal injury and apoptosis ● infection and inflammatory response later affect penetrating cortical vessels, resulting in swelling and proliferation of the endothelial cells of the arterioles...
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This note was uploaded on 02/18/2012 for the course PAS 600 - 601 taught by Professor Garrubba during the Fall '10 term at Chatham University.
- Fall '10