35 - Cerebrovascular Disease

Abstract

A stroke (‘brain attack’) is neurological dysfunction from a focal infarction in the central nervous system or retina, within a cerebrovascular territory, and based on clinical and/or objective (e.g., radiological) evidence. A transient ischaemic attack (TIA) is a focal neurological dysfunction lasting less than 24hours (usually minutes) and with no evidence of infarction. Ischaemic strokes comprise 85% of all strokes, and in the majority the underlying mechanism is either vessel pathology that leads to occlusion (e.g., atherothrombosis) or a source (e.g., heart) generating a ‘particle’ that results in embolic occlusion of a vessel (e.g., cardiac). A third group of ischaemic stroke involves occlusion of cerebral small vessels that results in small subcortical infarctions within the territory of those perforating arterioles and on neuroimaging (and postmortem) the appearance of fluid-filled cavities called lacunes, hence the name lacunar strokes. Fifteen percent of acute strokes are haemorrhagic, either intracerebral (10%) or from subarachnoid haemorrhage (5%). Nontraumatic subarachnoid haemorrhage is most frequently (80%) the result of rupture of an intracranial aneurysm (‘berry aneurysm’); morbidity is significant, and mortality is up to 50%. The predictability of the vascular supply to the brain allows specific stroke syndromes (neurological findings associated with involvement of different cerebral vessels) to be identified and when supported by various imagining techniques, facilitates further diagnostic and therapeutic decisions. The Clinical Panels describe the expected clinical findings associated with strokes resulting from specific cerebral vessel involvement.