Pathophysiology of Meningitis

Most cases of bacterial meningitis occur due to nasopharyngeal colonisation by causative organisms. Organisms invade in the submucosa and inhibit the host defences by gaining access to CNS by the bloodstream. 

Vascular endothelial injury and increased blood-brain permeability lead to the entry of many blood components in the subarachnoid space. This contributes to cerebral oedema and increases CSF protein levels. Cerebral oedema contributes to intracranial hypertension and a consequent decrease in cerebral blood flow.  

 

Anaerobic metabolism ensues, which contributes to increased lactate and decrease glucose concentrations. If all conditions are not treated abruptly can lead to transient neuronal dysfunction and permanent neuronal injury.