Hypertension Flashcards
Definition of hypertension
a blood pressure which is associated with significant cardiovascular risk and treatment is beneficial
Major varieties of hypertension
primary/central (95%) - no single obvious cause
secondary - some other medical condition which causes it
Causes of secondary hypertension
renal disease, renovascular disease Conn's syndrome, Cushing's syndrome hyperthyroidism phaeochromocytoma pregnancy drugs - NSAIDs, corticosteroids, sympathomimetics
Which organ is the main control of BP?
kidneys
Conn’s syndrome
excess aldosterone produced
causes increased sodium retention and therefore increased BP
Cushing’s syndrome
excess corticosteroids
sodium retention, augment sympathetic NS
Hyperthyroidism
excess thyroid hormone increases SNS
Phaeochromocytoma
young p
severely hypertensive
tumour secreting NA and adrenaline
Causes of primary hypertension
obesity insulin resistance XS alcohol genetics - activity of RAAS environment fetal programming eg. low birth weight salt sensitivity age ethnicity
How does obesity cause hypertension?
production of
How does insulin resistance cause hypertension?
metabolic syndrome, resistant to insulin
type II diabetes
Goals of treatment
and why?
control BP with as few side effects as possible
generally no symptoms of hypertension (if benefits outweigh SEs)
keep SBP <140; DBP <80
reduction in CV damage, preservation of renal function, limitation or reversal of LV hypertrophy, prevention of THD, reduction in mortality due to stroke and MI
Drugs used to treat hypertension
ACEIs AT1 receptor antagonists calcium channel blockers diuretics alpha-blockers beta-blockers centrally acting antihypertensives
How do ACEIs treat hypertension?
inhibits conversion of angiotensin I to II
prevent vasoconstriction - reduces TPR
prevents production of aldosterone - reduces sodium and water retention
Side effect of ACEIs
potentiate bradykinin - cough
hyperkalaemia - increased K
severe first dose hypotension
What is contraindicated with ACEIs?
and why?
renovascular diease - bilateral renal artery stenosis
BP is very RAAS-dependent
ACEIs cause substantial drop in BP
potentially causing kidney failure
pregnancy - angiotensin II involved in vascular and renal development of fetus
What are ACEIs effective for (besides hypertenstion)?
prevention of diabetic nephropathy - slows down renal damage
therefore ACEIs are best choice for ps with diabetes and hypertension
How do AT1 receptor anntagonists treat hypertension?
block action of angiotensin II at AT1 receptor
therefore prevents vasoconstriction and production of aldosterone
Why might AT1 receptor antagonists be preferred over ACEIs?
they are less likely to cause a cough
How do calcium channel blockers treat hypertension?
they are vasodilators
inhibit voltage operated Ca2+ channles on vascular smooth muscle - leads to vasodilation and reduction in BP
Types of calcium channel blockers and their predominant effect
rate-limiting: cardiac tissue (IHD) eg. verapamil
DHPs: vascular smooth muscle eg. amlodipine
Contraindication of rate-limiting CCBs
heart failure
How do diuretics treat hypertension?
act on kidney inhibit Na+/Cl- transporter in distal convoluted tubule prevention of Na and water retention reduction in circulating volume (vasodilators)
Example of diuretics used for hypertension
thiazide-like eg. indapamide
moderate diuretics
