5 - Pathophysiology of Hypertension

Abstract

There is considerable blood pressure (BP) variability throughout the day, depending on physical activity, stresses, and various environmental influences. These rapid changes in BP are mediated mainly via the sympathetic nervous system (SNS) or vasoactive hormones that alter vascular resistance or cardiac output. However, long-term BP regulation is also closely linked to salt and water homeostasis. Although hypertension is a heterogeneous disorder, kidney dysfunction and impaired renal pressure natriuresis occur in all forms of chronic hypertension studied thus far. Kidney dysfunction leading to sustained hypertension can be caused by a complex interplay of genetic and environmental factors that influence intrarenal, neurohormonal, immune, and inflammatory systems. Excess weight gain and increased visceral adiposity account for as much as 65% to 78% of the risk for increased blood pressure in patients with primary hypertension, although other factors such as high salt intake, sedentary lifestyle, and genetic predisposition may compound the impact of excess weight gain on BP. With prolonged obesity and development of kidney injury, hypertension becomes more difficult to control, often requiring multiple antihypertensive drugs and treatment of other risk factors, including dyslipidemia, insulin resistance and diabetes, and inflammation that can exacerbate hypertension and target organ injury.