Inflammation in acute ischemic stroke and its relevance to stroke critical care

Thrombolysis heralded a new era of acute intervention for ischemic stroke, accompanied by an increasing need for comprehensive acute critical care support. There remains the prospect of novel cerebral protection strategies. Cerebral ischemia initiates a complex cascade of events at genomic, molecular, and cellular levels, and inflammation is important in this cascade, both in the CNS and in the periphery. Closely linked events are induction of a classic acute phase protein response, activation of the hypothalamic-pituitary-adrenal axis (HPAA) and sympathetic nervous system (SNS), and rise in body temperature, all of which appear to importantly influence the outcome. Thrombolysis aside, various therapeutic strategies have been trialed without success recently, primarily directed at influencing neuronal activity and survival directly. Inflammation itself offers an attractive target, mainly because of its potential to exacerbate the spread of damage to the ischemic penumbra. A promising novel therapeutic approach is the interleukin-1 receptor antagonist (IL-1ra), which limits the action of the cytokine IL-1, a pivotal mediator in the pathophysiology of acute neurodegeneration. Critical care has much to offer some patients after acute ischemic stroke, including the delivery of acute interventions, often with very short therapeutic time windows, physiological support, and the management of complications. We discuss inflammation and its mediators in acute ischemic stroke, the systemic stress, and acute phase protein responses to acute ischemic stroke, how inflammation is relevant in deteriorating ischemic stroke, the impact of physiological variables, and both current and emerging interventions for acute ischemic stroke.