Pathogenesis of stroke

Different pathological processes may cause similar clinical events in cerebrovascular disease.

•        Completed stroke-One of four mechanisms is the usual cause.

1.     Arterial embolism from a distant site and subsequent brain infarction.

2.    Atheromatous carotid or vertebral artery occlusion and subsequent brain infarction.

3.    Atheromatous arterial throm

     bosis within a cerebral vessel and subsequent brain infarction.

4.    Hemorrhage in the brain.

•       Transient ischemic attack (TIA) -TIA are usually result of the passage of microemboki, small areas of brain infarction following thrombosis or hemorrhage may occasionally cause a clinical TIA. The principle sources of emboli to the brain are thrombi and atheromatous  plaques within the great vessels, the carotid and vertebral systems, or in the heart. Thromboembolism from sources outside the brain generates 70% of all strokes and 80% of TIAs. Of patients presenting with a stroke, 85 with have sustained a cerebral infarction infarction due to inadequate blood flow to pare of the brain. 

The remainder will have had an intracerebral hemorrhage. rupture of microaneurysms and decoration of the walls of small deep penetrating arteries is the principle pathology. In this setting hemorrhage is usually massive, often fatal and occurs in chronic hypertension and at well defined sites –basal ganglia, Pons, cerebellum and subcortical white matter. The causes of SAH are rupture of saccular aneurysms, Arterionvenous malformation Idiopathic.More details