56. Stroke. Ischaemic strokes in the carotid system · Neurology · MU Plovdiv

Ischemic stroke

Clinical syndrome characterized by a sudden onset of a focal neurological deficit due to infarction of the brain.
The deficit persists for longer than 24 hours or leads to earlier death.
Occurs when there are ischaemia and necrosis of an area of the brain following a reduction of the blood supply below the critical level necessary for cell survival.

Genetic predisposition
Environmental risk factors
Definite cerebrovascular risk factors
Ischemia usually results from thrombi or emboli. Even infarcts classified as lacunar often involve small thrombi or emboli.
Thrombosis (70%)
Atheromas, particularly if ulcerated, predispose to thrombi. Atheromas can occur in any major cerebral artery and are common at areas of turbulent flow, particularly at the carotid bifurcation.
Less common causes of thrombosis include vascular inflammation secondary to disorders.
Embolism from the heart (20%)
Emboli may lodge anywhere in the cerebral arterial tree.
Blood disease (<5%)
Non-atheromatous arterial disease (e.g. dissectation, arteritis) (5%)
Lacunar infarcts
Ischemic stroke can also result from lacunar infarcts. These small (≤ 1.5 cm) infarcts result from nonatherothrombotic obstruction of small, perforating arteries that supply deep cortical structures; the usual cause is lipohyalinosis (degeneration of the media of small arteries and replacement by lipids and collagen). Lacunar infarcts tend to occur in elderly patients with diabetes or poorly controlled hypertension.
Less commonly, ischemic stroke results from vasospasm (e.g. during migraine, after subarachnoid hemorrhage, after use of sympathomimetic drugs such as cocaine or amphetamines) or venous sinus thrombosis (e.g. during intracranial infection, postoperatively, peripartum, secondary to a hypercoagulation disorder).