Hypertension and Public Health

Pathophysiology & Hypertension

In majority of individuals with established primary high blood pressure, high pressure is due to increased resistance to blood flow while cardiac output remains normal. There are reports showing some younger individuals with prehypertension having high cardiac output and normal peripheral resistance. It is known as hyperkinetic borderline hypertension. For these individuals, as their cardiac output falls and peripheral resistance rises with age, they develop the typical features of established essential hypertension in later life. Whether the same pattern is being followed for each individual who finally develops hypertension is debatable. In established hypertension, although a reduction in the number or density of capillaries may also contribute, the increased peripheral resistance is mainly due to structural narrowing of small arteries and arterioles. Isolated systolic hypertension is a condition found in elderly people in which the systolic pressure is abnormally high, but diastolic pressure may be normal or low. There are many mechanisms which have been proposed to account for the rise in peripheral resistance. The most evident mechanisms found are either disturbances in the kidneys' salt and water handling or abnormalities of the sympathetic nervous system. This session is going to emphasize on different pathophysiology of hypertension.