Why does hypertension predispose to intracerebral haemorrhage?
Some 10–15% of all strokes are due to intracerebral haemorrhage [1] and many infarcts show evidence of some extravascular bleeding. This may range from a few petechiae to more florid haemorrhage with blood interspersed with intact brain. The latter situation may be difficult to classify clinically [2]. Minor changes are usually categorized as ‘haemorrhagic infarcts’, which have a good prognosis [3] but, even at necropsy, classification is difficult. At first sight, it seems obvious that high arterial pressure must necessarily increase the risk of arterial rupture and bleeding into the substance of the brain. However, even thin-walled arteries are extremely strong. Brain arteries taken at necropsy from previously normotensive people can withstand distending pressures as high as two atmospheres (1520 mmHg) and are usually forced off the cannula before rupture. Even large cerebral arteries from previously hypertensive people are almost equally strong. Lampert and Müller [4] were only able
