Pathophysiology of Hypertension Flashcards Preview

MD3001 Cardiology > Pathophysiology of Hypertension > Flashcards

Flashcards in Pathophysiology of Hypertension Deck (28)
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1
Q

What is systemic arterial hypertension?

A

the condition of persistent non-physiologic elevation of system blood pressure

2
Q

What figures suggest hypertension?

A
  • systolic >140 mmHg

- diastolic >90 mmHg

3
Q

What are the risk factors for hypertension?

A
  • age (under 60s more prevalent in males, over 60s more prevalent in females)
  • weight
  • sex
  • race (African Americans disproportionally affected)
  • education status
  • diet
4
Q

Stage 1 hypertension

A
  • clinical BP 140/90 or higher

- ABPM/HBPM daytime average of 135/85 or higher

5
Q

Stage 2 hypertension

A
  • clinic BP 160/100 or higher

- ABPM/HBPM daytime average of 150/95 or higher

6
Q

Severe hypertension

A
  • clinical systolic BP 180 or higher

- clinic diastolic BP 110 or higher

7
Q

Contributing factors of primary hypertension

A
  • weight
  • lifestyle (Na intake, lack of exercise, smoking, alcohol)
  • genetics
  • organ systems
8
Q

Components in controlling blood pressure

A
  • cardiac output (SV x HR)
  • TPR
  • effective circulating volume (by the kidneys)
9
Q

Contributors to systemic hypertension

A
  • increased sympathetic activity/sensitivity
  • RAAS
  • circulating factors
10
Q

Sympathetic neutrotransmission in ANS

A

in kidneys:

  • preganglionic fibre synapses in adrenal medulla on chromaffin cell on a and B receptors
  • releases ACH
  • releases adrenaline

in smooth muscle, glands and cardiac muscle:

  • preganglionic fibe synapses on post-ganglionic fibre near organ on a and b receptors
  • releases ACH
  • releases noradrenaline
11
Q

What binds to a and b-receptors?

A
  • adrenaline
  • noradrenaline
  • isoprenaline
12
Q

What are the affinities of the catecholamines for the a-receptors?

A

NA = A&raquo_space; ISO

13
Q

What are the affinities for the catecholamines for b-receptors?

A

ISO > A > NA

14
Q

Sympathetic activity contribution to hypertension

A
  • increased signalling to vascular smooth muscle in blood vessels (a1)
  • increased vasoconstriction and TPR
  • increased signalling to pacemaker and contractile cells in heart (b1)
  • increased HR, contraction and CO
  • adrenaline and renin secretion
  • increased angiotensin II, vasoconstriction and TPR
  • increased ECV
15
Q

What receptors does angiotensin II act on?

A

AT1 receptors

16
Q

What structures are affected by angiotensin II?

A

vascular smooth muscle cells of blood vessels:

  • increased vasoconstriction
  • increased TPR

Hypothalamus:

  • increased release of ADH
  • increased reabsorption of water in kidneys
  • increase in ECV

Zona Glomerulosa of adrenal glands:

  • increased secretion of aldosterone
  • increased Na+ reabsorption by kidney
  • increased ECV
17
Q

What is secondary low renin hypertension known as?

A

Conn’s Syndrome

18
Q

What is low renin hypertension?

A
  • plasma aldosterone : renin ratio

- low renin, normal aldosterone

19
Q

Higher risk patients of low renin hypertension?

A
  • older

- Afro-caribbean descent

20
Q

What circulating factors affect hypertension?

A
  • endothelin
  • nitrous oxide
  • reactive oxygen species
21
Q

Endothelin in hypertension

A
  • vasoconstrictor
  • circulating concentrations not increased in hypertension but locally can be
  • can bind ETa receptors on vascular smooth muscle cells to cause vasoconstriction
  • can also bind ETa receptors in cardiomyocytes to increase contractility
22
Q

Contradictions of endothelin in hypertension

A
  • can bind to ETb receptors to produce NO causing vasodilation
  • promotes salt and water excretion in kidneys
23
Q

Difference in secondary to primary hypertension

A

secondary hypertension has an identifiable underlying cause whereas primary hypertension does not

24
Q

Secondary hypertension caused renally

A

Renal parenchymal disease:

  • glomerularnephritis
  • diabetic nephropathy
  • lupus nephritis
  • polycystic kidney disease

Renal vascular disease:

  • renal artery stenosis
  • vasculitis
  • fibromuscular dysplasia
25
Q

Secondary hypertension caused by endocrine problems

A

adrenal gland

  • zona glomerulosa: aldosterone problems - Conn’s syndrome
  • zona fasiculata: cortisone problems - Cushing’s syndomr
  • adrenal medulla: adrenaline/noradrenaline problems - pheochromocytoma
26
Q

What conditions can cause secondary systemic hypertension?

A
  • pregnancy (eclampsia/pre-clampsia)
  • coarctation of aorta
  • drugs (contraceptive pill/cocaine/amphetamines)
  • obstructive sleep apnoea
27
Q

What are the consequences of systemic hypertension?

A

Heart:

  • heart failure
  • pressure overload, LVH
  • MI

Vasculature:

  • accelerated atherosclerosis
  • stroke
  • retinopathy

Kidneys:

  • continued hypertension
  • albuminuria
  • end stage renal disease
28
Q

Treatment of systemic hypertension

A

Lifestyle modifications:

  • weight-loss
  • reduced salt intake
  • increase fruit and veg intake
  • reduce alcohol
  • increase aerobic exercise
  • stop smoking
  • stress reduction

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