Flashcards in Lec 15 HTN Deck (67):
What are cutoff numbers for hypertension in normal person?
systolic BP > 140 mmHg and/or
diastolic BP > 90 mmHg
How do you diagnose hypertension?
2 readings separated apart
pt should not ingest caffeine or smoke for 30 min before reading
sit for 5 min with arm at heart level before BP is checked
What is prevalence of hypertension?
more prevalent with age
about 30% of population
What are the 4 systems determine of BP regulation?
- heart [CO]
- peripheral vasculature [tone]
- kidney [regulate blood volume]
- hormones/reflexes [modulate]
What is role of heart in BP regulation?
provides CO that fills the vascular tree
What is role of peripheral vasculature in BP regulation?
vascular tone/resistance --> modulates tone from heart
What is role of kidney in BP regulation?
- regulates intravascular volume
- essential to maintain chronic HTN state --> w/out renal involvement cannot maintain HTN
What is equation for BP [MAP]?
MAP = CO * TPR
What is equation for CO?
CO = HR*SV
What factors determine SV?
- venous return [preload]
What factors determine venous return [preload]?
What is renal regulation of BP?
kidneys sense drop in BP --> secrete renin --> converts angiotensinogen to AT1 --> ACE converts to AT II
--> directly increase BP by constriction
--> causes aldosterone release --> Na/H2O retention --> increase volume
What is essential hypertension?
cause of HTN cannot be explained == multiple etiologies together increasing CO or TRP
makes of 90% of HTN
What is secondary hypertension?
hypertension attributed to definable cause
makes up 10% of HTN
What is pressure natriuresis?
homeostatic mechanism by which if you increase BP --> get increase urine volume and Na excretion --> decrease blood volume --> pressure back to normal
this process is blunted in kidneys of pt with HTN
What is baroreceptor reflex?
baroreceptors = in aortic arch and carotid sinuses; sense increase in stretch of aorta due to pressure --> baroreceptors stimulated --> increase PNS and inhibit SNS--> vasodilation + decrese HR and co --> BP drops back to normal
== moment to moment modulation of blood pressure
What nerves carry baroreceptor signals?
CN IX carries from carotid sinus
CN X from aortic arch
What are causes of essential hypertension?
- black > white > asian
- systemic abnormalities: sympathetic overactivity in response to stimulus, abnormally vasoconstricted
- renal: excess Na/H2O retention, hormone dysregulation [normal renin level in HTN pt]
Is diastolic or systolic or both HTN most prevalent?
- in young people mostly isolated diastolic HTN
- as you get older = more and more isolated systolic HTN
b/c chronic exposure to hemodynamic stress, vessels stiffer, increase calcification --> higher systolic when push the blood into aorta but don't have sufficient elastic recoil --> low diastolic
What are some clinical clues that should make you think it might be secondary HTN?
- very young < 20 yo
- new HTN after age 50 in someone who never had problem before
- severe rapid onset
What are major causes of secondary HTN?
mostly renal disease including fibromuscular dysplasia in young patient
What are renal causes of secondary HTN?
- parenchymal damage to kidneys --> decrease # of functioning nephrons --> secrete less Na/H2O --> more blood volume --> CO/BP up
What lab findings if renal cause of secondary HTN?
- high serum creatinine
- abnormal urinalysis
What is renovascular cause of 2ndary HTN?
renal artery stenosis due to atherosclerosis or fibromuscular dysplasia
stenosis --> reduced renal blood flow --> more renin --> RAAS = vasoconstriction + Na retention
What is treatment of renovascular secondary HTN?
renal artery revascularization
What are clinical signs of renovascular hypertension?
unexplained hypokalemia [due to overactive aldosterone]
What is aortic coarctation?
congenital narrowing of aorta
What should you think it pt with HTN and way higher BP in arms than legs?
aortic coarctation causing secondary HTN
coarctation located distal to left subclavian
What should you think if pt with HTN and lower BP in left vs right arm?
aortic coarctation causing secondary HTN
coarctation located at origin of left subclavian
What happens in aortic coarctation associated hypertension?
- reduced blood flow to kidneys --> stimulate RAAS --> higher level Ang II and vasoconstriction
What are signs that hypertension might be due to aortic coarctation?
- blood pressure discrepancy
- midsystolic murmur
- rib notching on CXR= collaterals
What is pheochromocytoma? how does it cause HTN?
- catecholamine-secreting tumor
- release NE/E --> vasoconstriction + tachycardia
- have palpitations/tachy/headache
- diagnose based on catecholamine level in serum/urine
What is treatment for pheochromocytoma?
alpha and beta blockade
What are endocrine causes of secondary hypertension?
too much Ne/E --> pheochromocytoma
too much aldosterone --> primary [conn syndrome] or secondary [renin secreting tumor]
too much cortisol [Cushing]
How do you differentiate between primary and secondary aldosteronism as cause for HTN
primary = conn syndrome = adrenal adenoma or hyperplasia adrenal glands --> high aldosterone so suppresses renin
= high ratio aldosterone:renin
secondary = renin secreting tumor --> lots of renin --> causes lots of aldosterone
= low ration ald:renin
Why does cushing syndrome cause HTN?
- excess cortisol stimulates RAAS
also have: round face, central obesity, prox muscle weakness
how does hyperthyroidism cause HTN?
- cardiac hyperactivity/high HR --> increase BP/blood volume
how does hypothyroidism cause HTN?
increase in peripheral vascular resistance
What medications/drugs cause HTN?
- oral contraceptives
- sympathetomimetics [OTC cold remedies]
What are consequences of chronic HTN?
physio/structural derangements - increase work of heart, arterial damage, loss of elasticity, endothelial dysfunction
How much does CV risk change with each increase in 20/10 mmHG BP increment?
What are cardiac effects of HTN?
ventricular hypertrophy due to high afterload --> ventricular stiffness --> diastolic HF
CAD: HTN --> development atherosclerosis --> decreased myocardial O2 supply --> increased work
Is most common form of heart failure in elderly diastolic or systolic?
What is hemorrhagic stroke?
rupture microaneurysms induced by long-standing HTN
What is ischemic stroke?
thrombosis of atherosclerotic plaque in cerebral vessel --> get embolism of plaque which causes ischemia
What is aortic aneurysm? Where is it usually found?
prominent abnormal aortic dilation
most common in abdominal below level of renal arteries
if it ruptures you die
associated with HTN
What is aortic dissection?
ripping between intima and media in aorta; can be in ascending or descending aorta
associated wtih HTN
What is a hypertensive urgency?
SBP > 180 or DBP > 110 without evidence of end-organ damage
need immediate evaluation but does not need hospital admission
What is hypertensive emergency?
severe HTN [SBP > 180, DBP > 110] with evidence of acute organ damage
need immediate hospitalization
What are symptoms of hypertensive emergency
- hypertensive encephalopathy = mental status changes, headache, blurred vision
- SOB [pulm edema]
- papilledema on fundoscopy
What does it mean if abnormal K in HTN?
sign of too much aldosterone --> may be primary or secondary aldosteronism or renovascular problem
What are non-pharm treatments for HTN?
- weight [each 10 kg = 5-20 mmHG drop in BP]
- salt restriction < 6g/day
Why give a diuretic in HTN? For who?
- decrease circulating volume, CO
- give in mild-moderate HTN with normal renal function
- good for uncomplicated HTN
Why give Beta blocker in HTN? For who?
- reduce HR and contractility --> reduce CO + decrease renin
- reduces mortality if you've had MI or in heat failure
What are side effects of beta blockers?
bronchospasm [asthma], fatigue, sex effects
Why give alpha-2 adrenergic agonists in HTN?
Reduce sympathetic outflow
poor side effects, dont usually use
Why give alpha 1 antagonists in HTN?
relaxes smooth muscle + reduces prostatic enlargement
= good for older men
What meds do you give if primary essential uncomplicated HTN?
- ACE inhibitors/ARBs
- Ca channel blockers
What meds do you give f HTN with CHF?
- ACE inhibitors/ARBs
- beta blockers in compensated
- aldosterone antagonists [spirinolactone]
What meds do you give if HTN with DM?
- ACEI/ARBs = main b/c protects against diabetic nephropathy
- Ca channel blockers
- b blcokers
- a blockers
Why do you give ACE inhibitor in HTN?
reduce mortality in pts with acute MI, chronic HF or at high risk for vascular disease
good for diabetic nephropatyn
side effects = dry cough, hyperkalemia
When do you use spironolactone?
in symptomatic heart failure for HTN
mech = aldosterone blockade
When do you use eplerenone?
in pt with acute MI complicated by heart failure
= aldosterone blockade
What med for HTN pt pos-MI?
give beta blocker
What med for HTN if chronic kidney disease?
What med for HTN might you avoid in woman of child bearing age
ACE-I = teratogenic