Acute bacterial meningitis and stroke

Acute bacterial meningitis remains a common disease, especially in developing countries. Although advances over the last century have improved mortality and morbidity, the neurological adverse effects remain high. Specifically, acute ischaemic stroke is a serious comorbidity that represents both disease severity and poor prognosis. This review presents the clinical connection between meningitis and stroke, and discusses the neuroinflammatory components that have direct ties between these diseases.

Ischaemic stroke is the direct result of the inflammatory response produced to eradicate infectious pathogens. Bacterial virulence factors and pathogen-associated molecular patterns cause direct damage to the blood-brain barrier and trigger leukocytes to react to the infection. Cytokines are released that cause further destruction of the blood-brain barrier, lead to neuronal death, and recruit the prothrombotic effects of the coagulation cascade through the complement system. Unfortunately, this inflammatory response causes vasculopathy and hypercoagulation of the cerebral blood vessels, leading to cerebral ischaemia.

Pharmacological attempts to mitigate this inflammatory response have produced both positive and negative results. On the one hand, corticosteroids have been shown to improve mortality if given early in patients with bacterial meningitis, particularly pneumococcal meningitis. On the other hand, corticosteroids have been linked to delayed cerebral infarction and other adverse effects.

New targets for specific inflammatory markers have shown success in rodent models, but have not yet been proven beneficial in humans. Genetic markers are on the horizon, and may serve as individualised targets for diagnosis and therapy.