1. Hypertension Flashcards
What BP is indicative of stage 1 hypertension?
140/90
What BP is indicative of stage 2 hypertension?
160/100
What BP is indicative of stage 3 hypertension?
180/110
How is BP calculated?
CO x peripheral resistance
What factors control CO?
Na+, mineralocorticoids, ANP
HR and contractability
Name 3 factors that influence vasoconstriction
a-adrenergic receptors
angiotensin
catecholamines
Name 4 factors that influence vasodilation
B-adrenergic receptors
Prostaglandins
Kinins
NO
What are the risk factors for hypertension?
High BMI Salt intake Alcohol, smoking Inactivity Genetics
What is hypertension with an unknown cause called?
Essential hypertension
Why does Cushing’s syndrome increase the risk of hypertension?
High cortisol increases sensitivity of blood vessels to adrenaline and noradrenaline, both of which are vasoconstrictors
What are the functions of angiotensin 2?
Vasoconstriction and the release of aldosterone which causes Na retention
Where is angiotensinogen produced?
Liver
What enzyme converts angiotensinogen to angiotensin 1?
Renin
Why does COVID-19 cause vasoconstriction?
Turns off ACE-2 which converts angiotensin 2 to angiotensin 1-7
Angiotensin 1-7 have the effects of vasodilation and increasing NO
Why does Conn’s syndrome increase the risk of hypertension?
Increased aldosterone causes an increase in sodium retention
What are the causes of secondary hypertension?
Renal Adrenal Pituitary acromegaly eg. pregnancy CV eg. coarctation of aorta Alcohol and cocaine Increased ICP (cushing's response)
What are the adrenal causes of hypertension?
Excess aldosterone (conn's syndrome) Catecholamine excess
What causes Conn’s syndrome?
Hyperplasia or tumours of zona glomerulosa
What type of tumour causes a catecholamine excess?
Phaeochromocytoma
What type of hypertension is associated with phaeochromocytoma?
Paroxysmal
What are the endocrine causes of hypertension?
Thyroid over or under function
Pituitary tumour
Pre-eclampsia
What is pre-eclampsia and how does it cause hypertension?
Placental ischaemia causes the placenta to produce renin
How can hypertension be investigated?
Urinalysis
Bloods: glucose, lipids, U&Es
Fundoscopy
ECG
What is fundoscopy?
Examination of blood vessels of the retina
What can be seen on an ECG in hypertension?
LV hypertrophy seen as a larger QRS complex
What are the vascular consequences of hypertension?
Smooth muscle hypertrophy in media
Fibrosis and loss of elastic tissue can cause dissection and rupture berry aneurysms
Accelerated atherosclerosis
Luminal narrowing in kidney causes renal impairment
What is malignant hypertension?
> 120 diastolic BP
What does malignant hypertension cause?
Fibrinoid necrosis of vessels
This causes thrombosis and haemolytic anaemia (see forum)
What are the consequences of malignant hypertension?
Acute renal failure
Encephalopathy
Increase ICP
What are the cardiac consequences of hypertension?
LV hypertrophy (leading to an MI due to underperfusion) Sustained LV hypertrophy can cause dilatation which causes heart failure due to loss of pump function
What are the renal consequences of hypertension?
Nephrosclerosis (risk increased with other small vessel diseases)
Lack of perfusion triggers RAAS and worsens BP
What are the cerebrovascular consequences of hypertension?
Stroke
Rupture of pre-existing berry aneurysm
