Aetiology of hypertension Flashcards
What is hypertension ?
Is that blood pressure at which the benefits of treatment with antihypertensive agents in reducing cardiovascular , cerebrovascular and peripheral vascular risk outweigh the risks of treatment
When does someone have hypertension ?
140/90mmHg
What is the number 1 cause of preventable morbidity and mortality ?
Hypertension
What is the % increase risk mortality from IHD ?
7%
What is the % increase risk mortality from stroke ?
10%
What is the epidemiology of hypertension ?
affects 30-40% of the adult population
Prevalence >65% in persons over 60yrs
What are the risk factors for hypertension ?
MI
HF
Stroke
CVD
What does cigarette smoke do to BP ?
Adds 20/10mmHg
How much more times are males at risk ?
2X
How much more times are LVH at risk ?
2X
What are the most common causes of death due to raised blood pressure ?
Ischemic heart disease and stroke
What end organ damage is associated with hypertension ?
LVH, CHD, CHF, MI Renal failure, dialysis, transplantation, proteinuria Peripheral vascular disease Retinopathy Stroke
What is the defined as stage 1 hypertension ?
Clinical BP is 140/90mmHg or higher
ABPM daytime average 135/85mmHg or higher
What is defined as stage 2 hypertension ?
Clinic BP is 160/100mmHg or higher
ABPM daytime average 150/95mmHg or higher
What is defined as stage 3 or severe hypertension ?
Clinic systolic BP is 180/120mmHg or higher
What is primary hypertension ?
in 80-90% no cause can be found ?
What is secondary hypertension ?
In 10-20% a cause can be found ?
What are some of the causes of secondary hypertension ?
Chronic renal disease
Renal artery stenosis
Endocrine disease, Cushing’s
How is BP controlled ?
By an integrated system
What are the prime contributors to BP ?
Cardiac output
Stroke volume and heart rate
Peripheral vascular resistance
Each of these factors can be manipulated by drug therapy
The sympathetic NS activation produces what ?
Vasoconstriction - increases resistance
Reflex tachycardia
Increased stroke volume - increased cardiac output
What else does the sympathetic NS stimulate ?
Stimulates renin release which produces angiotensin II and aldosterone
What is the renin-angiotensin-aldosterone system responsible for ?
Maintenance of sodium balance
Control of BP
Control of blood volume
What is the renin-angiotensin-aldosterone system stimulated by ?
Fall in BP
Fall in circulating volume
Sodium depletion
What is the aetiology of hypertension ?
Polygenic:
- major genes
- poly genes
Polyfactorial:
- environment
- individual and sharedWhat does increased reactivity of resistance vessels result in ?
Increase in peripheral resistance
What is the sodium homeostatic effect ?
In hypertensive individuals the kidneys are unable to excrete appropriate amounts of sodium for any given BP, as a result sodium and fluid are retained and the BP increases
How does age contribute to hypertension ?
BP rises with age possibly as a result of decreased arterial compliance
We must be pragmatic, the elderly are more susceptible to adverse effects
How does genetics and family history contribute to hypertension ?
A history of hypertension tends to run in families
Between siblings rather than parents and child
How does environmental factors contribute to hypertension ?
Mental and physical stress both increases blood pressure
Removing stress does nor nescesaarlily return BP to normal values
How does salt intake and diet contribute to hypertension ?
Reducing salt intake in hypersensitive individuals to <5gm/day or 1.5/day
How does alcohol contribute to hypertension ?
Affects 1% of population
Small amounts of alcohol decrease BP
Large amounts of alcohol increase BP
How does weight contribute to hypertension ?
Obese pateints have a higher BP
Up to 30% of hypertension is attributable in part of wholly to obesity
How does race contribute to hypertension ?
Caucasians have lower BP than African populations
