Aetiology Pathophysiology of Hypertension

Question 1

What are the most common causes of death due to raised blood pressure?

Answer 1

Ischemic heart disease and stroke

Question 2

What end organ damage is associated with hypertension?

Answer 2

Question 3

Describe blood pressure throughout the day

Answer 3

Fluctuates widely -

Physcial stress and mental stress

Question 4

What is the definintion of hypertension?

Answer 4

That blood pressure above which the benefits of treatment outweigh the risks in term of morbidity and mortality

Question 5

What is the blood pressure distribution in a population?

Answer 5

Exhibits a normal bell shaped curve

Each population has its own bell shaped curvre

Question 6

What is the relationship between increased blood pressure and stroke/cardiovascular disease?

Answer 6

•Risk however rises exponentially and not linearly with pressure

Age also plays a significant role

Question 7

What is ‘optimal’ blood pressure in terms of american opinion?

Answer 7

Opt <120/<80

Question 8

What blood pressure is hypertension diagnosed at?

Answer 8

Varies - roughly 140/90

Question 9

What does ABPM stand for?

Answer 9

Ambulatory blood pressure monitor – measures blood pressure every half hour – inflates the cuff every half hour at night time?

Question 10

What is defined as stage 1 hypertension?

Answer 10

Clinic blood pressure is about 140/90 mmHg or higher

ABPM daytime average 135/85 mmHg or higher

Question 11

What is defined as stage 2 hypertension?

Answer 11

•Clinic blood pressure is 160/100 mmHg or higher

ABPM daytime average 150/95 mmHg or higher

Question 12

What is defined as stage 3 & severe hypertension?

Answer 12

Clinic systolic blood pressure is 180 mmHg or higher or diastolic blood pressure is 120 mmHg or higher

Question 13

What is more common, primary and secondary hypertension?

Answer 13

Primary - where no cause is found

90% of cases

Question 14

What are some of the causes of secondary hypertension?

Answer 14

Chronic renal disease

Renal artery stenosis

Endocrine disease - cushing’s, conn’s syndrome and paechromocytoma, GRA

Question 15

How many deaths worldwide is high blood pressure responsible for?

Answer 15

The number 1 medical cause of death world-wide

Directly and indirectly responsible for >20% of all deaths

Question 16

Which factors increase risks associated with hypertension?

Answer 16

Cigarette smoking

Diabetes mellitus - –5-30 X increase MI

Renal disease

Male - 2 x risk

Hyperlipidaemia

Previous MI or stroke

Left ventricular hypertrophy - 2 x risk

Question 17

What parts of the human body are responsible for blood pressure?

Answer 17

–Cardiac output

• Stroke volume
• Heart rate

–Peripheral vascular resistance

Question 18

What is the effect of the sympathetic nervous system on:

Stroke volume

Heart rate

Total peripheral resistance?

Answer 18

–increased cardiac output - contractility increases

–reflex tachycardia

–vasoconstriction

These increase blood pressure.

•The actions of the sympathetic system are rapid and account for second to second blood pressure control

Question 19

What type of blood pressure control is RAAS responsible for?

Answer 19

Long term

Question 20

What is RAAS responsible for?

Answer 20

Maintainance of sodium balance

Control of blood volume

Control of blood pressure

Question 21

What is RAAS stimulated by?

Answer 21

–fall in BP

–fall in circulating volume

–sodium depletion

• Any of the above stimulate renin release from the juxtaglomerular apparatus
• Renin converts angiotensinogen to angiotensin I
• Angiotensin I is converted to angiotensin II by angiotensin converting enzyme (ACE)
• Causes vasoconstriction

Question 22

Angiotensin is a potent?

Answer 22

Vasoconstrictor

Anti-natiuretic peptide

Stimulator of aldosterone release from the adrenal glands (aldosterone increases the reabsorption of sodium from the loop of henle - reduces diuresis)

Question 23

In general what are the aetiologies of hypertension?

Answer 23

–Polygenic

• Major genes
• Poly genes

–Polyfactorial

• Environment
• Individual and Shared

Question 24

What are the likely causes?

Answer 24

*Increased reactivity of resistance vessels and resultant increase in peripheral resistance

–as a result of an hereditary defect of the smooth muscle lining arterioles

*A sodium homeostatic effect

Kidneys unable to secrete sodium- Na & fluid retained

Question 25

Other factors

Answer 25

• Age
• Genetics and family history
• Environment – stressfulness brings about a high blood pressure
• Weight
• Alcohol intake – most common for young scotsmen
• Race – afrocarribean – hypertensive in western area – high salt diets

Question 26

How does blood pressure vary with age?

Answer 26

BP tends to rise with age, possibly as a result of decreased arterial compliance

Question 27

What are the dangers of treating the elederly for high blood pressure?

Answer 27

Lowering blood pressure too much can cause syncope - loss of confidence.

Question 28

What are the benefits of hypertehypertension treatment in the elderly?

Answer 28

–treating both diastolic and systolic hypertension in the elderly significantly reduces stoke and MI.

Question 29

Describe the trends in hypertension in the family

Answer 29

–A history of hypertension tends to run in families

–The closest correlation exists between sibs rather than parent and child - the children share same genes and environment

Environment plays a large influence in the development of hypertension

Question 30

What is the influence of stress?

Answer 30

–Mental and physical stress both increase blood pressure

–However removing stress does nor necessarily return blood pressure to normal values

–True stress responders who have very high BP when they attend their doctor but low normal pressures otherwise tend to be highly resistant to treatment

Question 31

What is the effect of reducing salt intake?

Answer 31

–Reducing salt intake in hypertensive individuals does lower blood pressure

–However reducing salt intake in normotensives appears to have little effect

–However there are real difficulties in achieving this level of salt restriction (fast food)

Question 32

What is the relationship between alcohol and blood pressure?

Answer 32

–Small amounts of alcohol tend to decrease BP

–Large amounts of alcohol tend to increase BP

–If alcohol consumption is reduced BP will fall over several days to weeks.

–Average fall is small 5/3 mmHg

Question 33

What is the relationship between obesity and blood pressure?

Answer 33

Obese patients have a higher blood pressure

Question 34

How much of hypertension is partly or completely attritable to obesity?

Answer 34

up to 30%

Question 35

What happens when an obese person loses weight?

Answer 35

Blood pressure falls

Question 36

How does birth weight affect chances of developing hypertension?

Answer 36

The lower the birth weight the higher the likelihood of developing hypertension and heart disease

Question 37

How does the blood pressure of caucasians and black populations compare when living in the same environment?

Answer 37

–Caucasians have a lower BP than black populations living in the same environment

–Black populations living in rural Africa have a lower BP than those living in towns

Question 38

What is the result of a stenosed kidney?

Answer 38

Produces a lot of renin - increases the bloods pressure

Question 39

How can you look for coartication in the clinical environment?

Answer 39

Produces a differences between radial pulses – narrowing slows pulse rate down