Pathology Bacterial Meningitis Infection of the pia mater and arachnoid the subarachnoi space, the ventricular system, and the CSf Infectious agents: Meningococcus(Neisseria meningitidis) pneumococcus (streptococcus pneumoniae URI---blood borne---CNS entry Inflammatory response by meninges, CSF, ventricles Neutrophils migrate producing exudate that plugs off CSF flow around the brain and spinal cord
Pathology • Bacterial Meningitis: – Infection of the pia mater and arachnoid, the subarachnoid space, the ventricular system, and the CSF – Infectious agents: • Meningococcus (Neisseria meningitidis) • pneumococcus (streptococcus pneumoniae) – URI---blood borne---CNS entry – Inflammatory response by meninges, CSF, ventricles – Neutrophils migrate producing exudate that plugs off CSF flow around the brain and spinal cord
Nasopharyngeal colonization Bloodstream invasion Bacteremia Meningeal invasion Bacterial multiplication in the subarachnoid space Release of bacterial products and cytokines immunocompetent cells endothelial cel and glial: cells Inflammation of the arachnoid space Breakdown of Cytokines and blood-brain barrier molecular mediators Increase of CsF outflow resistance Blood flow Hydrocephalus InterstiTial edema Cytotoxic edema Increased intracranial pressure Focal ischemia Cerebral ischemia Neuronal injury