Pathophysiology of Hypertension

Question 1

What is more common systemic or pulmonary hypertension?

Answer 1

Systemic

Question 2

How does decreased atmospheric oxygen cause pulmonary hypertension?

Answer 2

Reflex constriction of the blood supply to the lungs which leads to increased resistance resulting in pulmonary hypertension.

Question 3

What are the main causes of pulmonary hypertension?

Answer 3

• Hypoxia
• Endothelial dysfunction
• Left-sided heart failure
• Genetics
• Blockage/damage to pulmonary blood vessels (PE; sickle cell etc.)
• Side-effects of some drugs

Question 4

How is stage 1 hypertension defined?

Answer 4

• Clinic BP 140/90 mmHg or higher

- Home BP daytime average 135/85 mmHg or higher

Question 5

How is stage 2 hypertension defined?

Answer 5

• Clinic BP 160/100 mmHg or higher

- Home BP 150/95 mmHg or higher

Question 6

How is severe hypertension defined?

Answer 6

• Clinic systolic BP is 180 mmHg or higher

- Clinic diastolic is 110 mmHg or higher

Question 7

How does age affect CO and total peripheral resistance?

Answer 7

CO decreases and TPR increases

Question 8

What percentage of hypertension is primary?

Answer 8

> 90% (~95%)

Question 9

What is the difference between primary and secondary hypertension?

Answer 9

Secondary hypertension has a direct known cause, primary has no identifiable secondary cause.

Question 10

What can cause primary hypertension as a result of an increase in total peripheral resistance?

Answer 10

• Balance between contraction/relaxation changes
• Increased sympathetic nerve activity (increased firing rate or an increase in NA released [pre-synaptic effects of adrenaline and angiotensin II])

Question 11

What are the possible causes of primary hypertension through increased vascular reactivity?

Answer 11

• Increased Na+
• Pathological Na+/K+ATPase inhibition
• Damage to endothelium (therefore decreased NO production)
• Altered blood vessel wall morphology (increased wall thickness to lumen ratio)

Question 12

What are the major causes of secondary hypertension?

Answer 12

• Chronic renal disease
• Endocrine disorders
• Coarctation of the aorta
• Renovascular
• Certain drugs
• Pregnancy (eclampsia, pre-eclampsia)

Question 13

What endocrine disorders can cause secondary hypertension?

Answer 13

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

Question 14

What drugs can cause secondary hypertnesion?

Answer 14

• Contraceptive pill
• Cocaine, amphetamine
• NSAIDs
• Some herbal remedies

Question 15

What are the major causes of death as a result of hypertension?

Answer 15

• Heart Failure (50%)
• MI (20%)
• Stroke (20%)
• Renal failure (10%)

Question 16

What can hypertension cause in the eyes?

Answer 16

Retinopathy

Question 17

Describe the pathology of retinopathy

Answer 17

• Retinal blood vessels damaged by high pressure
• Arteries become narrowed and tortous
• Subsequently veins occluded and oedema and haemorrhage occurs
• Show cotton-wool spots

Question 18

How does hypertension affect the kidneys?

Answer 18

• Arterial walls thicken and narrow
• Kidney function declines irreversibly (sclerosis due to fibroblast activity)
• Urine formation falls
• Volume overload
• Decreased clearence of creatinine, urea and waste products
• Albuminuria