Pathological changes in small cerebral arteries causing occlusion and haemorrhage.

The resistance arteries of the brain contain relatively small amounts of muscle and elastic tissue. As a result of chronic hypertension, the small arteries develop microaneurysms at points of least resistance. Plasma leaking into the damaged wall leads to lipohyaline change. The end-result is either occlusion of the artery, causing a lacunar infarct, or rupture, causing intracerebral haemorrhage.