Pathophysiology of Hypertension

Question 1

What type of hypertension is most common?

Answer 1

Systemic

Question 2

Why is pulmonary hypertension less common?

Answer 2

May be idiopathic or associated with other diseases and is usually only diagnosed when severe and symptomatic

Question 3

Causes of pulmonary hypertension

Answer 3

• Hypoxia (decreased perfusion of the lungs)
• Endothelial dysfunction
• Genetics
• Blockage/damage to pulmonary blood vessels (PE, sickle cell)
• Side effects of some drugs
• Left sided heart failure

Question 4

What is abulatory blood pressure monitoring

Answer 4

when your blood pressure is being measured as you move around, living your normal daily life. Normally carried out over 24hrs

Question 5

What is stage 1 systemic hypertension?

Answer 5

140/90mmHg or higher

(ABPM = 135/85mmHg)

Question 6

What is stage 2 hypertension?

Answer 6

160/100mmHg or higher

(ABPM = 150/95mmHg)

Question 7

What is severe/stage 3 hypertension?

Answer 7

BP is higher than 180mmHg systolic and higher than 110mmHg diastolic

Question 8

What occurs in BP as you get older?

Answer 8

• CO decreases
• TPR increases

Question 9

What is the cause of primary hypertension?

Answer 9

idiopathic or essential

Question 10

What percentage of all cases of hypertension is primary hypertension?

Answer 10

>90%

Question 11

What is secondary hypertension?

Answer 11

Hypertension with a known cause

Question 12

What are the 2 main possible causes of primaru hypertension?

Answer 12

• Increased TPR
• Increased vascular reactivity

Question 13

What occurs when there is an increase in TPR?

Answer 13

• Balance between contraction/relaxation changes
• Increased sympathetic nerve activity
  
  • Increased firing rate
  • Increased NA released (pre-synpatic effects of adrenaline and angiotensin II)

Question 14

What occurs when there is an increase in vascular reactivity?

Answer 14

• Increased [Na⁺]_ECF
• Pathological Na⁺/K⁺- ATPase inhibition
• Damage to endothelium = decreased NO production
• Altered blood vessel wall morphology = increased wall thickness to lumen ratio

Question 15

What is nitric oxide?

Answer 15

Vasodilator substance

Question 16

What occurs in the CNS to cause primary hypertension?

Answer 16

• Increased basal sympathetic tone
• abnormal stress response
• abnormal response to signals from baroreceptors and volume receptors

Question 17

What occurs in the blood vessels to cause primary hypertension?

Answer 17

• Decreased NO secretion
• Increased endothelin production
• Ca²⁺ or Na⁺/K⁺ channel defects
• Hyperresponsiveness to catecholamines
• Exagerrated medial hypertrophy

Question 18

What occurs in the adrenal gland to cause primary hypertension?

Answer 18

Catecholamine leak or malregulation

Question 19

What occurs in the baroreceptors to cause primary hypertension?

Answer 19

desensitisation

Question 20

What occurs in the kidney to cause primary hypertension?

Answer 20

• RAA dysfunction
• Ion channel defects **upregulation of renin release

Question 21

Causes of secondary hypertension

Answer 21

• Chronic renal disease
• Endocrine disorders
• Coarctation of the aorta
• Renovascular
• Drugs
• Pregnancy; pre-eclampsia, eclampsia

Question 22

Give examples of the endocrine disorders that can cause secondary hypertension

Answer 22

• Cushing’s
• Conn’s/Primary aldosternosism
• Pheochromocytoma

Question 23

Risk factors for hypertension

Answer 23

• Age
• Modifable factors
• Genetic factors
• Psychogenic factors

Question 24

What are the modifable factors that cause hypertension?

Answer 24

• Excercise
• Diet
• Obesity
• Smoking
• Alcohol intake
• Stress

Question 25

What are the genetic factors that cause hypertension?

Answer 25

* Abnormal inhibition of Na/K - ATPase * Family history * Being african or caribean in origin * Male

Question 26

What are the psychogenic factors that cause hypertension?

Answer 26

personality type

Question 27

What factors affect TPR by increasing SNS activity?

Answer 27

* Psychogenic factors * Baroreceptor adaptation (high = new normal) * Presynaptic effects

Question 28

What factors affect TPR by increasing vascular reacitivy?

Answer 28

* Damage to endothelium * Na/K - ATPase inhibitor * Dietry alterations of K and Na * Blood vessel structural changes

Question 29

What are the major causes of sudden death due to hypertension

Answer 29

* Heart failure * myocardial infarction * Stroke * renal failure

Question 30

What occurs in heart failure?

Answer 30

* Pressure overload from increased TPR; LV hypertrophy * Volume overlaod due to kidney failure; decreased actin-myosin overlap

Question 31

How does hypertension affect the vasculature?

Answer 31

* Accelerated atherosclerosis * Stroke * Retinopathy

Question 32

What occurs in renal failure due to hypertension?

Answer 32

* Autoregulation stops protecting the glomerulus * Albuminuria * Contained high pressure * Arteriolar walls thicken and narrow (sclerosis due to fibroblast activity) * Urine formation falls * Volume overload * Decreased clearance of creatine, urea and waste

Question 33

What affects does stage 1 hypertension have on the heart?

Answer 33

* Normal size * Normal ECG

Question 34

What affects does stage 2 hypertension have on the heart?

Answer 34

* LV hypertrophy * Left axis deviation

Question 35

What affects does stage 3 hypertension have on the heart?

Answer 35

* Marked LV hypertrophy * Increased left axis deviation * Inverted T waves

Question 36

What affects does stage 1 hypertension have on the blood vessels/renal?

Answer 36

* Narrowed retinal arteries * Renal function normal

Question 37

What affects does stage 2 hypertension have on the blood vessels/renal?

Answer 37

* Retinal vein changes * Microalbuminuria but renal function = OK

Question 38

What affects does stage 3 hypertension have on the blood vessels/renal?

Answer 38

* Retinal oedema/haemorrhage * Marked albuniburia * Falling creatine clearance