Patho - Exam 3 Alterations in Blood Pressure
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- Does pressure increase or decrease as it goes thru the vascular system?
- Pressure decreases d/t resistance to flow. The further it goes, the more resistance it encounters.
- What are the main determinants of BP?
- CO and total peripheral resistance
- mean arterial pressure =
- diastolic pressure + 1/3 pulse pressure
- What blood vessels are most resistant?
- arterioles
- List 6 ways BP is controlled.
-
1. sympathetics (maintain baseline vasoconstriction)
2. baroreceptors (in the medulla)
3. hormones (epi and norepi)
4. renin (angiotensin from a decrease in renal perfusion)
5. atrial natriuretic factor (from response to stretch receptors)
6. ADH (causes vasoconstriction, retains water) - norm for pulmonary BP:
-
systolic: 22-25 mmHg
diastolic: 8 mmHg - 2 measurements of arterial BP:
-
1. indirect (cuff, palpitation, doppler)
2. direct (cath in artery) - hypertension:
-
systolic > 140 mmHg
diastolic > 90 mmHg - 4 risk factors of HTN:
- age, race, obesity, excess Na intake
- 2 classifications of HTN:
- essential (primary) and secondary
- Which classification of HTN is most common?
- primary (90%)
- 5 causes of Essential HTN:
-
1. genetic (no indication of disease)
2. elevation of renin activity (not very common)
3. aldosterone increase
4. vasopressin
5. Non-insulin Dependent Diabetes Mellitus (NIDDM) - secondary HTN:
- -HTN results from an existing disorder
- Name 5 disorders that can cause secondary HTN.
-
1. renal
2. endocrine
3. vascular
4. neurological
5. exogenous - How does a renal disorder cause secondary HTN?
-
1. renal artery stenosis
2. Wilm's tumor
3. renal failure
4. renal disease - renal artery stenosis:
- -reduces renal perfusion causing an increase in renin production
- How common are renal disorders in adults and children?
-
5% in adults
70-90% in children - Wilm's tumor:
-
-cancerous tumor in the kidney
-increases renin production
-common in children under 7 YO. - How do endocrine disorders cause secondary HTN?
-
-causes elevated levels of adrenocortical hormones
-can cause Cushings disease, pheochomocytomas and hyperthyroidism - Cushing's disease:
- -overproduction of glucocorticoid causing fluid retention and HTN
- pheochomocytomas:
-
-tumor of the adrenal medulla
-massive production of epineph and norepinepherine - What 2 vascular disorders cause secondary HTN?
-
1. arteriosclerosis
2. coarctation of aorta - coarctation of aorta:
-
-narrowing of aorta
-typically thoracic
-increases pressure in the brain
-BP is taken on upper and lower extremities
-decreases perfusion to the lower part of the body - How do neurological disorders cause secondary HTN?
-
1. causes an increase intracranial pressure
2. increased pressure on the medulla or hypothalamus - What exogenous compounds cause secondary HTN?
-
-amphetamines, corticosteroids, oral contraceptives, tricyclic antidepressents
-caffeine and nicotine - isolated systolic HTN:
-
-reduced distensibility of aorta and large arteries
-common with elderly
10% ages 65-74
24% >80 - pre-eclampsia:
-
-pregnancy induced HTN
-also causes proteinuria and edema
-usually after 20th week
-chronic HBP increases risk of this - malignant HTN:
-
-sudden increases of diastolic BP >120mmHg
-highest risk in African amer, males, middle-aged ppl - What disorders are most common with malignant HTN?
- renal complications and bilateral renal artery stenosis
- What type of disease is high blood pressure?
- asymptomatic disease
- What are the 2 major effects of high blood pressure?
-
1. cardiac (hypertrophy leading to CHF)
2. vascular (changes in walls of arteries/arterioles leading to arteriosclerosis) - What is a nickname for hypertension?
- "silent killer"
- List the S/S of HTN.
-
1. LV hypertrophy
2. development and rupture of aortic aneurysm
3. peripheral arteriosclerosis (occlusions)
4. cerebro-vascular accidents
5. hypertensive retinopathy
6. renal changes - hypertensive retinopathy:
-
-can see blood vessels in the eyes
-common in pts with diabetes - How to diagnose HTN:
-
-multiple readings for accuracy (could be a "white coat syndrome")
-evaluate end organs (?) - Lifestyle treatment of HTN:
-
1. lose weight
2. restrict alcohol intake
3. resrict Na intake (1.5-2.5 g/day)
4. stop smoking
5. restrict fat intake
6. aerobic exercise - Pharmacological treatment of HTN:
-
1. diuretics (watch K+ levels)
2. beta-blockers
3. Ca-channel blockers - List the types of hypertensive crisises:
-
1. perioperative HTN
2. increased intracranial pressure
3. dissecting aneurysms
4. intravenous agents in ICU setting - orthostatic hypotension:
- -sudden decrease BP (sys >20, dia >10) caused by a change in body position
- What are 2 causes of orthostatic hypotension?
-
1. Na depletion causing a decrease in blood volume; syncope results
2. cardiovascular-inadequate peripheral vasoconstriction or inadequate increase in HR - How does orthostatic hypotension affect the nervous system?
-
-interrupts normal sympathetic body reactions such as increased HR and contraction
-most common with pts on beta blockers - List 3 forms of treatment for orthostatic hypotension.
-
1. slow down position changes
2. treat the underlying problem
3. lower pressure can be normal for an individual (ie atheletes)