CHAPTER 25–27 HYPERTENSION Flashcards
5 ADVERSE EFFECTS OF HYPERTENSION
–acceleration of atherogenesis
–Elevated systolic and diastolic pressures are independent risk
–often occurs in combination with other risk factors such as dyslipidemia, glucose intolerance, hyperinsulinemia, obesity
–Association of hypertension and other risk factors is multiplicative rather than additive
what is the increase in cardiovascular disease associated with elevated blood pressures
115/75, cardiovascular disease risk doubles with each increase of 20/10
percent reduction in risk with blood pressure treatment
with drug therapy for hypertension:
–stroke decreases by 35%
–Myocardial infarction decreases by 20%
–Heart failure decreases by 50%
classification of high blood pressure
<120 and <80 = normal
120–139 or 80–89 = pre-hypertension
140–159 or 90–99 = stage I hypertension
>160 or >100 = stage II hypertension
prevalence of hypertension worldwide
–about 1 billion persons worldwide with hypertension
–About 70 million deaths per year worldwide
–Increased prevalence in developing countries
–#1 cause of preventable death in developing countries
prevalence of hypertension in US adults
–30% of adults in US have hypertension
–30 million men
–35 million women
percent of patients with hypertension who are aware of disease
76% are aware of disease
65% receiving medication
37% have controlled hypertension
etiology of hypertension
–most often results from increased total peripheral vascular resistance
–Increased cardiac output places lesser part
physiologic causes of hypertension
–inappropriate activation of renin–angiotensin system.
–Decreased renal sodium excretion.
–Increase in sympathetic nervous system activity
environmental factors and hypertension
–excess sodium intake
–Obesity
–Stress
discuss isolated systolic hypertension
–correlates with stiffening of large arteries
–Increase in systolic pulse-wave velocity
–Causes increase in systolic blood pressure and increased myocardial work with decrease coronary perfusion
clinical presentation of hypertension
usually asymptomatic
cardiac manifestations of hypertension
result from hypertrophic effects of increased afterload and acceleration of coronary atherosclerosis caused by hypertension
left ventricular hypertrophy discussion
Left ventricular hypertrophy is powerful and independent risk factor for cardiovascular morbidity.
–Is usually concentric hypertrophy = increase in wall thickness relative to chamber dimensions
myocardial fibrosis discussion
stimulated in part by angiotensin II and aldosterone levels
–Causes decreased ventricular compliance and diastolic dysfunction
–May result in congestive heart failure despite normal ventricular systolic function
coronary artery disease and hypertension
hypertension is independent risk factor for coronary artery disease.
–LVH and accelerated atherosclerosis combine to greatly enhanced risk for congestive heart failure and cardiovascular death
characteristics of patients with diastolic heart failure
–tend to be older, female and hypertensive
–Less mortality
–Normal left ventricular ejection fraction
–Typically long-standing hypertension and LVH
malignant/accelerated hypertension
–very high systolic and diastolic pressures
–Severe neuroretinitis
–Proteinuria
–Microscopic hematuria
–Impairment of renal function
Other symptoms caused by proliferative endocarditis and fibroid necrosis and small arteries
differential diagnoses of hypertension
–95% have essential hypertension.
–5% is secondary hypertension
–Obesity is contributing factor to essential hypertension.
drugs causing secondary combined systolic and diastolic hypertension
–oral contraceptives –Estrogens –licorice –Cyclosporine –Cocaine –Amphetamines –Sympathomimetics –Monoamine oxidase inhibitors
secondary causes of isolated systolic hypertension
increased left ventricular STROKE VOLUME –COMPLETE HEART BLOCK –AORTIC REGURGITATION –PATENT DUCTUS ARTERIOSUS –HYPERTHYROIDISM –ARTERIOVENOUS FISTULA –SEVERE ANEMIA –BERIBERI –PAGET'S DISEASE OF BONE
Decreased aortic distensibility
–Aortic arteriosclerosis
–Coarctation of aorta
indications for searching for secondary hypertension
–age of onset <20 years –Age of onset >50 years –target organ damage –Serum creatinine >1.5 mL/deciliter –Hypokalemia –Abdominal bruit –Labile pressures with tachycardia, sweating, and tremor –Family history of renal disease –Poor response to generally effective therapy
DASH diet
= dietary approach to stop hypertension
–fruits, vegetables, low-fat dairy products,
–Rich in potassium, magnesium, and calcium
–Low in sugar, red meat, added fats,sodium
first-line hypertension drugs
Dyazide diuretics Beta-adrenergic receptor blockers Angiotensin-converting enzyme inhibitors Angiotensin receptor blockers Calcium antagonists
defining hypertensive crisis
acute organ dysfunction of the cardiovascular nervous system accompanying either by a marked absolute elevation of blood pressure 1 her blood increase in blood pressure in a previously normotensive individual
antihypertensives contraindicated in pregnancy
ACE inhibitor,
angiotensin receptor blocker
antihypertensive contraindicated in renal insufficiency
potassium sparing agents is a relative contraindication
antihypertensives contraindicated in peripheral vascular disease
beta blocker
antihypertensive contraindicated in gout
diuretic
antihypertensives contraindicated in depression
–beta blocker
–Central alpha agonist
common central alpha agonist medications
–clonidine
–Guanfacine
–Methyldopa
percentage of middle-aged persons and United States with high blood pressure
20%
common causes of secondary hypertensionin elderly
–renal parenchymal disease
–Atherosclerotic renal artery stenosis
causes of renal artery stenosis
–atherosclerosis= 90%
–Fibromuscular dysplasia = 10%
pathogenesis of renal artery stenosis
–same as generalized atherosclerosis obliterans –Smoking –Dyslipidemia –Hypertension –Glucose intolerance –Genetic predisposition
definition of renal vascular hypertension
= secondary to atherosclerotic renal artery sclerosis or fibromuscular dysplasia, causing a decrease in renal perfusion pressure
define high-grade renal artery stenosis
> 60% of lumen of major renal artery
–Accounts for 3% of cases of hypertension
–Does not always cause hypertension
smoking and renal artery stenosis
90% of older patients with renal artery stenosis are or have been heavy smokers
–Usually Other atherosclerosis
discussed renal artery stenosis caused by fibromuscular dysplasia
–presents at younger age
–Common in women under 50 years old
–Can occur in children
+/- Abdominal bruit
differential diagnosis of renal vascular hypertension and essential hypertension
–in older people with peripheral vascular disease, prevalence of atherosclerotic renal artery stenosis is high EKG up to 50%.
–Prevalence of essential hypertension in this group is 60%.
–Therefore difficult to separate
diagnosis of renal artery stenosis
–Gold standard his renal arteriogram showing stenosis of proximal third of the renal artery
–fibromuscular dysplasia shows characteristic areas of stenosis alternating with aneurysmal dilation dictation = “string of pearls”
– Renal arteriogram is expensive, invasive, and does not provide information on function.
–Doppler ultrasound of renal arteries is often used, but less predictable and more operator dependent
treatment renal artery stenosis
–surgical revascularization with balloon angioplasty and/or vascular stent
–Medical treatment= treatment of underlying causes and lifestyle
mechanism of secondary hypertension caused by adrenal cortex
–overproduction of aldosterone
–Overproduction deoxy corticalsterone
–Overproduction of cortisol
examples of mineralocorticoids versus glucocorticoids
mineralocorticoids
–Aldosterone
–desoxy corticosterone (DOC)
glucocorticoids
–Cortisol
function of mineralocorticoids in secondary hypertension
increase salt and water retention by kidney
function of glucocorticoids and secondary hypertension
marked hypersecretion of cortisol can stimulate mineralocorticoid receptors and cause a release of DOC and vasoconstrictors
normal control of aldosterone secretion
by renin-angiotensin system
–ACTH and serum potassium concentrations less important
mechanism of hypertension caused by aldosterone
increased stimulation of mineralocorticoid receptors and a cortical collecting ducts of the kidney
–Causes (of sodium channels leading to increased tubular reabsorption of sodium and secondary reabsorption of water
–Also increased secretion of potassium and hydrogen ions
idiopathic hyperaldosteronism
= 30% of patients with hyper aldosteronism
–Surgically curable aldosterone producing adenoma
Two thirds have bilateral adrenal gland hyperplasia
clinical presentationof primary aldosteronism
–hypertension –Hypokalemia –Excessive urinary excretion of potassium –Suppressed plasma renin activity –Mild hyponatremia –Metabolic alkalosis
symptoms of hypokalemia
–polyuria –Polydipsia –Muscle cramps –Muscle weakness –Glucose intolerance
suspect primary aldosteronism when
–hypertension with spontaneous hypokalemia
–Hypertension with severe and refractory diuretic induced hypokalemia
–Family history of hyperaldosteronism
–Unexplained hypertension, refractory to treatment
–Unexplained hypertension in children and young adults
–Incidentally discovered adrenal tumor
testing for primary aldosteronism
measure plasma aldosterone concentration and plasma renin activity
treatment of primary aldosteronism
–surgical adrenalectomy
–Spironolactone
discuss pheochromocytoma
= a tumor arising from adrenal medullary chromaffin cells that produces excess secretion of catecholamines causing intermittent or sustained hypertension
symptoms of pheochromocytoma
hypertension with triad of headache, sweating, palpitations
Other common symptoms –Pallor –Nausea –Tremor –Weakness –Anxiety –Epigastric pain –Chest pain –Flushing –Dizziness
hypertension and Cushing’s disease
–hypertension may be severe
–Target organ damages is common
