Hypertension - Pathophysiology, Presentation & Investigation Flashcards
Define hypertension.
High blood pressure
What are the possible complications of hypertension for the heart?
(4)
- left ventricular hypertrophy
- coronary heart disease
- congestive heart failure
- myocardial infarction
What are the possible complications of hypertension for the eyes?
(1)
retinopathy
What are the possible complications of hypertension for the peripheries?
(1+)
- peripheral vascular disease: peripheral blood vessels block, narrow or spasm
What are the possible complications of hypertension for the brain?
(4)
- haemorrhage/aneurysm
- stroke
- cognitive decline
- dementia/Alzheimer’s,
What are the possible complications of hypertension for the kidneys?
(4)
- Renal Failure
- Dialysis,
- Transplantation
- Proteinuria
What is one of the most devastating consequences to hypertension?
- stroke - leads to death and permanent disability
- (CV disease second)
What can be said about blood pressure through the course of the day?
What factors influence this? (hint: both are similar) (2)
Blood pressure is a continuous variable which fluctuates widely during the day.
- physical stress
- mental stress
A person is considered hypertensive when their systolic pressure is ______ or above and diastolic pressure is ______ or above.
140mmHg
90mmHg
Risk rises exponentially and not linearly with pressure.
What does this tell us about hypertension and how it affects different people?
a persons age has a significant role.
What is the target blood pressure for adults?
And what is considered a normal blood pressure?
<120/80 mmHg
Systolic: 120-129mmHg
Diastolic: 80-84mmHg
What is considered a normal-high (pre-hypertensive) BP?
2
Systolic: 130-139mmHg
Diastolic: 85-89mmHg
How does the risk of cardiovascular disease and strokes change with increasing blood pressure?
it is an exponential increase
What factor also plays a part in the risk of cardiovascular disease and stroke with hypertension?
age
What is the optimum bp that must be aimed for in hypertensives?
<120/<80 mmHg
What is ABPM and what is its advantage over clinical blood pressure?
(2)
- ambulatory blood pressure monitoring
- it provides a more accurate measure of blood pressure as blood pressure measured in the clinic tends to be higher than normal.
If an elderly person aged 70 had a blood pressure of 140/90mmHg, would we be concerned or happy with this?
How would this BP be classified?
happy
it is in the upper region of normal (normal-high)
What is the clinic BP for type I hypertension, according to NICE guidelines?
How would this BP be classified?
140+/90+ mmHg
Stage 1, beyond pre-hypertensive
What is the clinic BP for type II hypertension, according to NICE guidelines?
How would this BP be classified?
160+/100+ mmHg
- high
What is the clinic BP for type III hypertension, according to NICE guidelines?
How would this BP be classified?
180+/110+
- severe hypertension
What percentage of hypertensive cases are idiopathic?
What is the term for this?
90%
primary hypertension
What is the ABPM for type I hypertension?
daytime average 135/85 mmHg
What is the ABPM for type II hypertension?
daytime average 150/95 mmHg
Who is secondary hypertension more likely to be found in?
younger (<40), perhaps in children
What are some causes of secondary hypertension?
3
- chronic renal disease
- renal artery stenosis
- endocrine disease
What are examples of endocrine diseases where hypertension can become a complication of?
(4)
- Cushngs
- Conn’s syndrome
- phaechromocytoma
- GRA
Despite the clear relationship between BP and morbidity the risk from hypertension also depends on and increases exponentially with other factors.
What are they?
(7)
- Cigarette smoking
- Diabetes
- Renal disease
- Male
- Hyperlipidaemia
- Previous MI or stroke
- Left ventricular hypertrophy
If cigarette smoking itself does not raise blood pressure, why does smoking carry an equivalent risk of raising systolic pressure by 20mmHg?
(2)
- Smokers suffer from lower fitness than non-smokers.
- Low fitness is the largest risk factor which kills hypertensive patients.
How does having diabetes affect a the risk of MI in a hypertensive patient?
increases that risk by 5-30x
What is the increased risk of morbidity due to hypertension of a male compared to a female?
2x
What is the risk of morbidity of a hypertensive patient who smokes and has diabetes?
(2)
- much higher than the two risks combined.
- diabetes and smoking work synergistically to increase risk of morbidity.
What are the two prime contributors to blood pressure?
- cardiac output (CO)
- total peripheral resistance (TPR)
What two factors influence cardiac output (CO)?
- stroke volume (SV)
- heart rate (HR)
Sympathetic nervous system activation produces which effects?
(3)
- vasoconstriction
- reflex tachycardia
- increased CO
What is the collective effect from all the mechanisms employed by the sympathetic nervous system?
- increased BP
What does it mean by the actions of the sympathetic system are rapid?
(2)
- rapid onset = fight or flight
- rapid fall in BP when threat goes away
What are the three functions of the renin-angiotensin aldosterone system, in terms of aim/outcome?
- maintenance of Na+ balance
- control of plasma volume
- control of BP (increases)
What is the renin-angiotensin aldosterone system is stimulated by? (3)
What happens when any of above are stimulated?
- fall in BP (MAP)
- fall in circulating volume
- sodium depletion (due to low filtrate production)
- renin is released from the juxtaglomerular
What course does renin go through?
2
- renin converts to angiotensin I (inactive)
- angiotensin I is then converted to angiotensin II by ACE.
Why is angiotensin II an active molecule?
It is a vasoconstrictor
Who tends to have high levels of AT I and AT II?
people of young age
How does AT II increase blood pressure?
2
- it is a vasoconstrictor (increase BP)
- it induces the release of aldosterone from the adrenal gland (increase BP)
Aldosterone is also a potent ___________ and __________ peptide.
antinatriuretic (ANP)
antidiuretic (ADH)
Both the ___________ and _______ are key targets in the treatment of hypertension.
sympathetic
RAAS
What does the hormone aldosterone do to increase blood pressure?
- increases Na+ reabsorption
- reduces diuresis
- increases PV/BP
The aetiology of hypertension is poly______ and ________.
polygenic
polyfactorial
What are the two most likely causes of hypertension?
- Increased reactivity of resistance vessels and resultant increase in TPR.
- a sodium homeostatic effect.
What causes hypertension in patients with a sodium homeostatic problem?
(2)
- kidneys unable to excrete appropriate amounts of Na+ for any given BP.
- Na+ and fluid are retained, PV increases, BP rises.
What are some other factors that can cause hypertension?
7
- age
- genetics and family history
- environment
- weight
- alcohol intake
- race
- Na+ intake
How does BP change with increasing age?
Why is this thought to happen?
it increases
- thought to be because arteries become more inelastic and compliance decreases.
Why is it important to treat hypertensive elderly just as aggressively as younger people?
(2)
- They have more to lose i.e. MI, stroke.
- they are more prone to side-effects of reduced BP, however we must be pragmatic about their overall health.
Between which family member’s does the closest correlation between hypertension exist?
siblings
What environmental factors increase the risk of hypertension?
(hint: similar)
(2)
mental and physical stress
What effect does reducing Na+ intake have on hypertensives?
What effect does reducing Na+ intake have on normotensives?
reduces BP
little effect
What is the correlations between alcohol consumption and blood pressure?
(2)
Small amounts of alcohol tend to reduce BP.
Large amounts of alcohol consumed chronically tend to increase BP.
How does weight loss effect blood pressure?
Is weight loss recommended for hypertensives?
it reduces it dramatically
Yes - it is the best non-pharmacological treatment for hypertension.
How does birth weight affect the likelihood of developing hypertension in later life?
Low birth weight increases likelihood of hypertension/CV disease in adult life.
Which ethnicities are most susceptible to hypertension?
black populations - reasons are unclear
With secondary hypertension, why does removal of the causing agent not guarantee improvement in blood pressure?
Sustained hypertension produced end-organ damage to blood vessels, heart and kidneys.
Outline the causes of secondary hypotension.
6
- renal disease
- drug induced
- pregnancy
- endocrine disease
- vascular
- sleep apnoea
Give examples of renal diseases which can cause secondary hypertension.
(4)
- renal artery stenosis
- fibromuscular dysplasia
- polycystic kidneys
- chronic pyelonephritis
What is chronic pyelonephritis?
inflammation and fibrosis of the kidneys associated with repeated infections
What is fibromuscular dysplasia?
narrowing of the arteries resulting in muscle overgrowth (hypertrophy)
What are the drug induced causes of secondary hypertension?
3
- NSAIDS
- oral contraceptive
- corticosteroids
What condition in pregnant women causes hypertension?
pre-eclampsia – rise in BP after 20th week.
Which endocrine disorders can cause hypertension?
5
- Conn’s syndrome - hyperaldosteronisms
- Cushing’s disease
- pheochromocytoma
- hypo- and hyper-thyroidism
- acromegaly
What vascular disease can causes secondary hypertension?
coarctation (stenosis) of the aorta