Ischemic stroke

Ischemic stroke is a neurological emergency caused by interruption of cerebral blood flow, usually because an artery is occluded by a thrombus, an embolus, or atherosclerotic disease. Reduced perfusion deprives brain tissue of oxygen and glucose, producing an ischemic core of irreversible injury surrounded by a potentially salvageable penumbra. Persistent ischemia can lead to infarct expansion, neurological deficits, disruption of the blood–brain barrier, oxidative stress, inflammation, microglial activation, neuronal injury, and apoptotic processes. Reperfusion may restore blood flow but can also contribute to cerebral ischemia-reperfusion injury and neuroinflammation.

Atrial fibrillation is an important source of cardioembolic ischemic stroke, while diabetes, hypertension, coronary artery disease, and other vascular conditions contribute to cerebrovascular risk. Clinical management focuses on rapid recognition, brain and vascular imaging, restoration of perfusion when appropriate, prevention of recurrent embolism or thrombosis, and rehabilitation. Oral anticoagulants are central to prevention in many patients with atrial fibrillation, although ischemic stroke or transient ischaemic attack can occur despite treatment. Outcomes may also be influenced by age, socioeconomic status, infarct volume, the affected vascular territory—such as the middle cerebral artery—and the severity of the initial neurological deficits.