Vascular pathology in hypertension.

The pathological changes in blood vessels observed in primary (essential hypertension) are similar to those seen in secondary hypertension due to renal disease or other causes. In benign hypertension, the major changes are in the small arteries and arterioles especially in the kidney. Interlobular arteries exhibit intimal thickening and duplication of the elastic lamina (elastosis) and there is hyaline change in the media of many arterioles. In some respects these changes are an accentuation of vessel ageing. Malignant hypertension usually presents in a younger age group (35--50 years) and is characterized pathologically by fibrous endarteritis in the interlobular arteries of the kidney and fibrinoid necrosis in the walls of a proportion of the efferent glomerular arterioles. Similar vessel changes are seen in other organs but many of the pathological changes in the heart and brain of patients with benign hypertension are related to the accentuation of arterosclerosis. There is an increased mortality from cardiac failure, myocardial infarction, cerebral haemorrhage and subarachnoid haemorrhage due to ruptured berry aneurysms in patients with benign hypertension. Although there is ischaemic damage to the kidneys in benign hypertension, death from renal failure is uncommon. Severe ischaemic damage to renal glomeruli and renal failure does, however, occur in malignant hypertension.