Hypertension pathophysiology


 * Assistant Editor-In-Chief: Taylor Palmieri

Overview
While the mechanisms underlying secondary hypertension are well understood, the mechanisms underlying primary or essential hypertension are poorly understood.

Time Dependence of Pathophysiology

 * Cardiac output is raised early in the disease course, while total peripheral resistance (TPR) is normal.
 * Over time cardiac output drops to normal levels but TPR is increased. Three theories have been proposed to explain this:
 * Inability of the kidneys to excrete sodium, resulting in natriuretic factors such as Atrial Natriuretic Factor being secreted to promote salt excretion with the side-effect of raising total peripheral resistance.
 * An overactive renin / angiotension system leads to vasoconstriction and retention of sodium and water. The increase in blood volume leads to hypertension.
 * An overactive sympathetic nervous system, leading to increased stress responses.

Genetics
Hypertension is highly heritable and polygenic (caused by more than one gene) and a few candidate genes have been postulated in the etiology of this condition.