[Arterial] hypertension (aka high blood pressure, HTN) is chronically elevated BP in arteries.
What is hypertension?
High blood pressure.
What is blood pressure?
The pressure of blood against the wall of the vessels, that contain it.
BP is expressed by systolic (maximum) and diastolic (minimum) pressures in the arterial system
The systolic pressure occurs when the L ventricle is most contracted, the diastolic pressure when the L ventricle is most relaxed prior to the next contraction
Normal BP at rest is between 100/60-140/90 systolic/diastolic, so HTN is present is BP>140/90 for aduts, and different numbers apply to kids
So normal blood pressure is 120/80. What is high blood pressure defined as?
The normal high is 140/90. So a systolic pressure greater than 140, or a diastolic pressure greater than 90, is called hypertension.
Primary (essential) hypertension (95%), with no obvious underlying cause. It tends to be familial, and is likely the consequence of an interaction between environmental and genetic factors. The prevalence of essential hypertension increases with age, and patients with relatively high blood pressure at younger ages are at increased risk for subsequent development of hypertension. It can increase the risk of cerebral, cardiac, and renal events
Secondary hypertension (5%), where HTN is due to an identifiable secondary cause, including:
Chronic kidney disease
Narrowing of the aorta or kidney arteries
Endocine disorder, e.g. excess aldosterone, cortisol, or catecholamines
Side effect of many drugs
What are the different types of high blood pressure?
Essential, where we don't know what the cause is. And secondary, where we can identify the cause.
Well then... what are the causes of high blood pressure?
The kidney excretes fluid, so if there's problem there, blood pressure will increase. There can be narrowing of an article somewhere, but it's particularly a problem if it's the vessel pumping blood out the heart, or the one in the kidney. Think about it, if the same amount of blood runs through a thinner tube, the pressure is higher. It can also be a hormone thing, causing the heart to beat faster, or the body to retain more water.
Dietary and lifestyle changes can improve BP control, and decrease risk of complications
Drugs, is often necessary in Pt's whom lifestyle changes are not enough or not effective
Tx of moderately arterial BP (>160/100mmHg) w/ drugs is associated w/ improved life expectancy
Benefits of drug Tx for BP 140/90-160/100 is more controversial