Hypertension – pathophysiology, presentation and investigation Flashcards
What is the definition of hypertension
the blood pressure above which the benefits of treatment outweigh the risks in terms of morbitdity and mortality
Sustained hypertension is a contributing risk factor to
end-organ damage to blood vessels, heart and kidney
Increasing blood pressure is associated with a progressive exponentially increase in the risk of
Stroke
Heart disease
As well as increasing high blood pressure what also increases the risk of stroke and heart disease
Increasing age
What is normal blood pressure
systolic pressure of 120–129 mmHg or a diastolic pressure of 80–84 mmHg
What is stage 1 hypertension according to NICE
Clinic blood pressure is 140/90 mmHg or higher
ABPM daytime average 135/85 mmHg or higher.
What is stage 2 hypertension according to NICE
Clinic blood pressure is 160/100 mmHg or higher
ABPM daytime average 150/95 mmHg or higher.
What is severe hypertension according to NICE
Clinic systolic blood pressure is 180 mmHg or higher or diastolic blood pressure is 110 mmHg or higher.
What is Ambulatory Blood Pressure Monitoring (ABPM)
when your blood pressure is measured as you move around, living your normal daily life. It is measured for up to 24 hours
How is ABPM more efficient
Gives a more realistic blood pressure, as measured throughout the day rather than one reading
What is the two aetiologies of hypertension
Primary hypertension - no unknown cause
Secondary hypertension - underlying cause
What is the proportion of primary hypertension and secondary hypertension
Primary = 90% Secondary = 5-10%
What is the aetiologies of secondary hypertension
Renal disease Drug induced pregnancy endocrine diseases Vascular diseases sleep apnoea
What increases the risk of hypertension development
Cigarette smoking Adds 20/10 mmHg Diabetes mellitus 5-30 X increase MI Renal disease Male 2X risk Hyperlipidaemia Previous MI or stroke Left ventricular hypertrophy 2X risk
What are the prime contributors to blood pressure than can be manipulated by drug therapy
Cardiac output
-Stroke volume
-Heart rate
Peripheral vascular resistance
What controls blood pressure
An integrates system ( SNS + RAAS)
What system is needed in log term control of BP
Renin angiotensin aldosterone system
What is RAAS responsible for
maintenance of sodium balance
therefore controlling blood volume
which in turn controls blood pressure
What is RAAS stimulated by
fall in BP
fall in circulating volume
sodium depletion
what is the result of stimulated RAAS
Renin released from juxtaglomerular apparatus
Renin converts angiotensinogen to angiotensin I
Angiotensin I is converted to angiotensin II by angiotensin converting enzyme (ACE)
What is the function of angiotensin II
vasoconstrictor
anti-natriuretic peptide
stimulator of aldosterone release from the adrenal glands
What does it means that angiotensin is a potent hypertrophic agent
stimulates myocyte and smooth muscle hypertrophy in the arterioles
What is the negative outcomes of angiotensin II being a potent hypertrophic agent
Arteries become narrower and cant dilate,
Unable to repsond to appropriate dilation
therefore more likely to split and become damaged
What controls short term effect of blood pressure
Sympathetic NS
What is the outcome to activation of the Sympathetic NS
vasoconstriction
reflex tachycardia
increased cardiac output
What is the problem with the Sympathetic NS
can be prolonged to long and result in hypertension
What is the pathologies of hypertension
Increased reactivity of resistance vessels and resultant increase in peripheral resistance (
A sodium homeostatic effect - Na cant be excreted, blood volume rises therefore BP increases
What is the major polygenic and poly factorial factors in hypertension
Age Genetics and family history Environment Weight Alcohol intake Race
Why does blood pressure increase with age
due to decreased arteriole compliance
How does genetics affect hypertension
Hypertension runs in the family
Families live together under the same environment therefore are at the same risk
What is the affect of reducing sodium intake in hypersensitive individuals
Reduces blood pressure
What is the recommended maximum salt intake a day
< 6mg
What is the affect of high and low alcohol intake on blood pressure
High -Increases BP
Low - Decrease BP
How does obesity increase blood pressure
Obesity activated sympathetic nervous system
Obesity linked to sleep apnoea which increase BP
Obesity is also linked to IL6 which links to hypertension
What is the most important non-pharmacological measure available
Weight reduction
How is birth weight and hypertension linked
The lower the birth weight the higher the likelyhood of developing hypertension
What is the possible reason for black populations to have a higher BP than caucasians
Black populations are genetically selected to be salt retainers and so are more sensitive to an increase in dietary salt intake or the environment
In secondary hypertension what is the affect on hypertension if cause is removed
There is no guarantee that BP will return to normal
What are examples of the renal diseases causing secondary hypertension
RENAL ARTERY STENOSIS
Further examples:
chronic pyelonephritis
- (destruction of renal tissue)
fibromuscular dysplasia
- (non-inflammatory disease of the blood vessels that causes abnormal growth within the wall of an artery)
polycystic kidneys
(abnormal cysts develop and grow in the kidneys)
What is examples of drug induced secondary hypertension
NSAIDs
Oral contraceptive
Corticosteroids
What is the name of the condition in pregnancy associate with high blood pressure
pre-eclampsia
What is example of endocrine conditions resulting in secondary hypertension
Conn’s Syndrome
(excess production of the hormone aldosterone by the adrenal glands resulting in low renin levels)
Cushings disease (tumour in the pituitary gland - vasoconstriction)
Phaeochromocytoma
(tumor of adrenal gland tissue - release to much epinephrine)
Hypo and hyperthyroidism
(over/under production of thyroid hormone = increase BP)
Acromegaly
(abnormal growth of the hands, feet, and face, caused by overproduction of growth hormone by the pituitary gland)
What vascular condition can result in secondary hypertension
Coarctation of the aorta
What respiratory condition can result in secondary hypertension
sleep apnoea
