L16 - Hypertension Flashcards
How many deaths per year in the US due to hypertension
One million
How does BP vary with age
Increases
How does BP vary with gender, what causes this?
Higher in males - due to presence of testosterone
Normal diastolic pressure
85
What would be considered a high normal diastolic pressure
85-89
What would be considered mild hypertension as a diastolic pressure
90-104
What would be considered moderate hypetension as a diastolic pressure
105-114
What diastolic pressure would be considered severe hypertension
Greater than 114
What systolic pressure would be considered normal
140 or below
What systolic pressure/s would be considered to be borderline systolic hypertension
140-159
What systolic pressure/s would be considered to be isolated systolic hypertension
Greater than 160
What do more recent BP guidelines suggest
BP should be kept as low as possible - but so that perfusion throughout the body can be maintained
What are the two types of hypertension
Essential hypertension
Secondary hypertension
Essential hypertnesion
Many risk factors but no clear cause
Can be spontaneous
Secondary hypertension
Consequence of a clinical condition
MABP is proportional to
CO x TPR
How does CO vary with age?
Why is this the case
Decreases
The heart is a mechanical pump - this will have a finite number of beats
How does TPR vary with age
Give examples of what causes this variation
Increases
Arteriosclerosis - stiffening of the vessels
What are the likely causes of essential hypertension
Cardiac dysfunction
Vessel abnormalities
Kidney dysfunction
Explain how kidney dysfunction could lead to essential hypertension
In the long term - unable to control total blood volume
Kidneys will naturally vary with age
Known as volume induced hypertnesion
Explain how cardiac dysfunction could lead to essential hypertension
Increased repsonse to stress and catecholamines, also increase sensitivity to cortisol
Leads to vessel constriction
What sorts of vessel abnormalities may lead to essential hypertension
Sympathetic NS abnormalities
Abnormalities of local factors
Smooth muscle hypertrophy
How may smooth muscle hypertrophy lead to EH - what is the name given for the process
Smooth muscle is made to work harder
Any further contractions will be more powerful - causing greater constriction
Leads to VASCULAR REMODELLING
Why is hypertension classed as a syndrome
Syndrome due to being caused by many different factors
EH is
Familial
Is EH genetic - evidence
Corrleation between twin studies
What races are of an increased EH risk
African-Caribbean
What are some known environmental risk factors for EH
Diet and obesity (metabilic syndrome)
Adopting a western lifestyle
Salt intake
Vit D deff syndrome
What is metabolic syndrome
Collection of symptoms which can lead to type 2 diabetes mellitus
What % of the population has a predisposition to Eh
30-50%
What are the common polymorphisms that contribute to EH
Angiotensinogen ENaC (epithelial Na channel)
What converts angiotensionogen to angiotensin I
Renin
What converts angiotensin I to angiotensin II
ACE
What is the ‘case against salt’
In human studies reduction of salt by 3g/day leads to reduced MABP of 5 mmHg
This is equivilant to drug therapy which reduces strokes
What was the problem with low salt (KCl)
Must be reduction in NaCl
What does aldosterone bind to what is its effect
Binds to mineralocorticoid R
Increases the reabsorpiton of Na
What are three potential causes of secondary hypertension
Renal disease
Renal artery stenosis
Hormone inbalance
How might renal disease lead to secondary hypertension
Nephron fucntion imparied
Blood volume and BP increases
More damage and kidney failure
Viscious circle
How might renal artery stenosis lead to secondary hypertension
Narrowing of the arteries
Caused by atheroscleosis
Increased renin production and increased BP
How might a hormone imbalance lead to secondary hypertension
Aldosterone increased the NA reabsorption leads to inc BP
If mini adrenal tumours ==> would change ammount of aldosterone produced
What is ateriosclerosis
Arteries become less compliant with age - vascular remodelling
What is arteriosclerosis
Deposition of cholesterol plaques reduced the diameter of the lumen
Symptoms of secondary hypertension
FLusing, sweating and blurred vission
USUALLY A-SYMPTOMATIC
Arterio/atherosclerosis
What is an aeurysm
Where is a common place for them to occur
Balooning of the arteries
Descending aorta
What are the typical sizes of arteries
2.5-8cm
Why can strokes present as a consequence of secondary hypertension
At high systolic pressure could burst the arteiries which enter the brain
Describe how necrotic tissue which has undergone infarction would be recognised
How would this interfere with the normal conduction of the heart
Would interfere with the conducting systems of the heart
How can retinal damage be used to diagnose secondary hypertension
Eye is the only place where blood vessels can be seen non invasively Small haemhorrages (spots) of hard and soft exudates would be indicative of hypertension
Give some non pharmacological treatments for secondary hypertension
Weight loss Diet (decrease in salt alcohol and caffine) Exercise Stopping Smoking Relaxation
What classes of drug may be used to treat secondary hypertension
Diuretics
Sympatholytics
Ca channel blockers
Drugs which interfere with the RAA sysytem
RAA system
Renin - angiotensin - aldosterone
Explain how diuretics may be used to treat secondary hypertension
Thiazdes would increase secretion of Na and Cl lowering the total blood volume
Explain how sympatholytics (two classes) may be used to treat secondary hypertension
Alpha blockers
Clonidine - decrease sympathetic outflow to reduce the vascular tone
Prazoin - relaxes the smooth muscle to cause a fall in TPR
Beta blockers
Propanolol - To decrease HR and decrease contractility
Describe how Ca channel blockers (BROAD SPECTRUM) may be used to treat secondary hypertension
Minoxidal
Decreases the contractility and the vascular tone
What is another use for minoxidal
Topical application for hair growth
Describe how selective Ca blockers may be used to treat hypertension
Manidipine
Relaxation of the vascualr smooth muscle H
How may ACE inhibitors be used to treat hypertension
E.g. moexipril
Inhibition of vascular remodelling
Prevention of the proliferation of the cells of the smooth muscle
Unwanted side effect of using ACE inhibitors
Bradykinin cough
Aside from ACE inhibitors what is a common treatment for secondary hypertension
AGII receptor blockers