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Hypertension And High Blood Pressure:
Hypertension is high blood pressure. Blood pressure is the force of blood pushing against the walls of arteries as it flows through them. Arteries are the blood vessels that carry oxygenated blood from the heart to the body's tissues.
Description
As blood flows through arteries it pushes against the inside of the artery walls. The more pressure the blood exerts on the artery walls, the higher the blood pressure will be. The size of small arteries also affects the blood pressure. When the muscular walls of arteries are relaxed, or dilated, the pressure of the blood flowing through them is lower than when the artery walls narrow, or constrict.
Blood pressure is highest when the heart beats to push blood out into the arteries. When the heart relaxes to fill with blood again, the pressure is at its lowest point. Blood pressure when the heart beats is called systolic pressure. Blood pressure when the heart is at rest is called diastolic pressure. When blood pressure is measured, the systolic pressure is stated first and the diastolic pressure second. Blood pressure is measured in millimeters of mercury (mm Hg). For example, if a person's systolic pressure is 120 and diastolic pressure is 80, it is written as 120/80 mm Hg. The American Heart Association has long considred blood pressure less than 140 over 90 normal for adults. However, the National Heart, Lung, and Blood Institute in Bethesda, Maryland released new clinical guidelines for blood pressure in 2003, lowering the standard normal readings. A normal reading was lowered to less than 120 over less than 80.
Hypertension is a major health problem, especially because it has no symptoms. Many people have hypertension without knowing it. In the United States, about 50 million people age six and older have high blood pressure. Hypertension is more common in men than women and in people over the age of 65 than in younger persons. More than half of all Americans over the age of 65 have hypertension. It also is more common in African-Americans than in white Americans.
Hypertension is serious because people with the condition have a higher risk for heart disease and other medical problems than people with normal blood pressure. Serious complications can be avoided by getting regular blood pressure checks and treating hypertension as soon as it is diagnosed.
If left untreated, hypertension can lead to the following medical conditions:
arteriosclerosis, also called atherosclerosis
heart attack
stroke
enlarged heart
kidney damage.
Arteriosclerosis is hardening of the arteries. The walls of arteries have a layer of muscle and elastic tissue that makes them flexible and able to dilate and constrict as blood flows through them. High blood pressure can make the artery walls thicken and harden. When artery walls thicken, the inside of the blood vessel narrows. Cholesterol and fats are more likely to build up on the walls of damaged arteries, making them even narrower. Blood clots also can get trapped in narrowed arteries, blocking the flow of blood.
Arteries narrowed by arteriosclerosis may not deliver enough blood to organs and other tissues. Reduced or blocked blood flow to the heart can cause a heart attack. If an artery to the brain is blocked, a stroke can result.
Hypertension makes the heart work harder to pump blood through the body. The extra workload can make the heart muscle thicken and stretch. When the heart becomes too enlarged it cannot pump enough blood. If the hypertension is not treated, the heart may fail.
The kidneys remove the body's wastes from the blood. If hypertension thickens the arteries to the kidneys, less waste can be filtered from the blood. As the condition worsens, the kidneys fail and wastes build up in the blood. Dialysis or a kidney transplant are needed when the kidneys fail. About 25% of people who receive kidney dialysis have kidney failure caused by hypertension.
Causes and symptoms
Many different actions or situations can normally raise blood pressure. Physical activity can temporarily raise blood pressure. Stressful situations can make blood pressure go up. When the stress goes away, blood pressure usually returns to normal. These temporary increases in blood pressure are not considered hypertension. A diagnosis of hypertension is made only when a person has multiple high blood pressure readings over a period of time.
The cause of hypertension is not known in 90 to 95 percent of the people who have it. Hypertension without a known cause is called primary or essential hypertension.
When a person has hypertension caused by another medical condition, it is called secondary hypertension. Secondary hypertension can be caused by a number of different illnesses. Many people with kidney disorders have secondary hypertension. The kidneys regulate the balance of salt and water in the body. If the kidneys cannot rid the body of excess salt and water, blood pressure goes up. Kidney infections, a narrowing of the arteries that carry blood to the kidneys, called renal artery stenosis, and other kidney disorders can disturb the salt and water balance.
Cushing's syndrome and tumors of the pituitary and adrenal glands often increase levels of the adrenal gland hormones cortisol, adrenalin, and aldosterone, which can cause hypertension. Other conditions that can cause hypertension are blood vessel diseases, thyroid gland disorders, some prescribed drugs, alcoholism, and pregnancy.
Even though the cause of most hypertension is not known, some people have risk factors that give them a greater chance of getting hypertension. Many of these risk factors can be changed to lower the chance of developing hypertension or as part of a treatment program to lower blood pressure.
Risk factors for hypertension include:
age over 60
male sex
race
heredity
salt sensitivity
obesity
inactive lifestyle
heavy alcohol consumption
use of oral contraceptives
Some risk factors for getting hypertension can be changed, while others cannot. Age, male sex, and race are risk factors that a person can't do anything about. Some people inherit a tendency to get hypertension. People with family members who have hypertension are more likely to develop it than those whose relatives are not hypertensive. People with these risk factors can avoid or eliminate the other risk factors to lower their chance of developing hypertension. A 2003 report found that the rise in incidence of high blood pressure among children is most likely due to an increase in the number of overweight and obese children and adolescents.
Diagnosis
Because hypertension doesn't cause symptoms, it is important to have blood pressure checked regularly. Blood pressure is measured with an instrument called a sphygmomanometer. A cloth-covered rubber cuff is wrapped around the upper arm and inflated. When the cuff is inflated, an artery in the arm is squeezed to momentarily stop the flow of blood. Then, the air is let out of the cuff while a stethoscope placed over the artery is used to detect the sound of the blood spurting back through the artery. This first sound is the systolic pressure, the pressure when the heart beats. The last sound heard as the rest of the air is released is the diastolic pressure, the pressure between heart beats. Both sounds are recorded on the mercury gauge on the sphygmomanometer.
Normal blood pressure is defined by a range of values. Blood pressure lower than 120/80 mm Hg is considered normal. A number of factors such as pain, stress or anxiety can cause a temporary increase in blood pressure. For this reason, hypertension is not diagnosed on one high blood pressure reading. If a blood pressure reading is 120/80 or higher for the first time, the physician will have the person return for another blood pressure check. Diagnosis of hypertension usually is made based on
two or more readings after the first visit.
Systolic hypertension of the elderly is common and is diagnosed when the diastolic pressure is normal or low, but the systolic is elevated, e.g.170/70 mm Hg. This condition usually co-exists with hardening of the arteries (atherosclerosis).
Blood pressure measurements are classified in stages, according to severity:
normal blood pressure: less than less than 120/80 mm Hg
pre-hypertension: 120-129/80-89 mm Hg
Stage 1 hypertension: 140-159/90-99 mm Hg
Stage 2 hypertension: at or greater than 160-179/100-109 mm Hg
A typical physical examination to evaluate hypertension includes:
medical and family history
physical examination
ophthalmoscopy: Examination of the blood vessels in the eye
chest x ray
electrocardiograph (ECG)
blood and urine tests.
The medical and family history help the physician determine if the patient has any conditions or disorders that might contribute to or cause the hypertension. A family history of hypertension might suggest a genetic predisposition for hypertension.
The physical exam may include several blood pressure readings at different times and in different positions. The physician uses a stethoscope to listen to sounds made by the heart and blood flowing through the arteries. The pulse, reflexes, and height and weight are checked and recorded. Internal organs are palpated, or felt, to determine if they are enlarged.
Because hypertension can cause damage to the blood vessels in the eyes, the eyes may be checked with a instrument called an ophthalmoscope. The physician will look for thickening, narrowing, or hemorrhages in the blood vessels.
A chest x ray can detect an enlarged heart, other vascular (heart) abnormalities, or lung disease.
An electrocardiogram (ECG) measures the electrical activity of the heart. It can detect if the heart muscle is enlarged and if there is damage to the heart muscle from blocked arteries.
Urine and blood tests may be done to evaluate health and to detect the presence of disorders that might cause hypertension.
Treatment
There is no cure for primary hypertension, but blood pressure can almost always be lowered with the correct treatment. The goal of treatment is to lower blood pressure to levels that will prevent heart disease and other complications of hypertension. In secondary hypertension, the disease that is responsible for the hypertension is treated in addition to the hypertension itself. Successful treatment of the underlying disorder may cure the secondary hypertension.
Guidelines advise that clinicians work with patients to agree on blood pressure goals and develop a treatment plan for the individual patient. Actual combinations of medications and lifestyle changes will vary from one person to the next. Treatment to lower blood pressure may include changes in diet, getting regular exercise, and taking antihypertensive medications. Patients falling into the pre-hypertension range who don't have damage to the heart or kidneys often are advised to make needed lifestyle changes only. A 2003 report of a clinical trial showed that adults with elevated blood pressures lowered them as mush as 38% by making lifestyle changes and participating in the DASH diet, which encourages eating more fruit and vegetables.
Lifestyle changes that may reduce blood pressure by about 5 to 10 mm Hg include:
reducing salt intake
reducing fat intake
losing weight
getting regular exercise
quitting smoking
reducing alcohol consumption
managing stress
Patients whose blood pressure falls into the Stage 1 hypertension range may be advised to take antihypertensive medication. Numerous drugs have been developed to treat hypertension. The choice of medication will depend on the stage of hypertension, side effects, other medical conditions the patient may have, and other medicines the patient is taking.
If treatment with a single medicine fails to lower blood pressure enough, a different medicine may be tried or another medicine may be added to the first. Patients with more severe hypertension may initially be given a combination of medicines to control their hypertension. Combining antihypertensive medicines with different types of action often controls blood pressure with smaller doses of each drug than would be needed for just one.
Antihypertensive medicines fall into several classes of drugs:
diuretics
beta-blockers
calcium channel blockers
angiotensin converting enzyme inhibitors (ACE inhibitors)
alpha-blockers
alpha-beta blockers
vasodilators
peripheral acting adrenergic antagonists
centrally acting agonists
Diuretics help the kidneys eliminate excess salt and water from the body's tissues and the blood. This helps reduce the swelling caused by fluid buildup in the tissues. The reduction of fluid dilates the walls of arteries and lowers blood pressure. New guidelines released in 2003 suggest diuretics as the first drug of choice for most patients with high blood pressure and as part of any multi-drug combination.
Beta-blockers lower blood pressure by acting on the nervous system to slow the heart rate and reduce the force of the heart's contraction. They are used with caution in patients with heart failure, asthma, diabetes, or circulation problems in the hands and feet.
Calcium channel blockers block the entry of calcium into muscle cells in artery walls. Muscle cells need calcium to constrict, so reducing their calcium keeps them more relaxed and lowers blood pressure.
ACE inhibitors block the production of substances that constrict blood vessels. They also help reduce the build-up of water and salt in the tissues. They often are given to patients with heart failure, kidney disease, or diabetes. ACE inhibitors may be used together with diuretics.
Alpha-blockers act on the nervous system to dilate arteries and reduce the force of the heart's contractions.
Alpha-beta blockers combine the actions of alpha and beta blockers.
Vasodilators act directly on arteries to relax their walls so blood can move more easily through them. They lower blood pressure rapidly and are injected in hypertensive emergencies when patients have dangerously high blood pressure.
Peripheral acting adrenergic antagonists act on the nervous system to relax arteries and reduce the force of the heart's contractions. They usually are prescribed together with a diuretic. Peripheral acting adrenergic antagonists can cause slowed mental function and lethargy.
Centrally acting agonists also act on the nervous system to relax arteries and slow the heart rate. They are usually used with other antihypertensive medicines.
Prognosis
There is no cure for hypertension. However, it can be well controlled with the proper treatment. Therapy with a combination of lifestyle changes and antihypertensive medicines usually can keep blood pressure at levels that will not cause damage to the heart or other organs. The key to avoiding serious complications of hypertension is to detect and treat it before damage occurs. Because antihypertensive medicines control blood pressure, but do not cure it, patients must continue taking the medications to maintain reduced blood pressure levels and avoid complications.
Prevention
Prevention of hypertension centers on avoiding or eliminating known risk factors. Even persons at risk because of age, race, or sex or those who have an inherited risk can lower their chance of developing hypertension.
The risk of developing hypertension can be reduced by making the same changes recommended for treating hypertension:
reducing salt intake
reducing fat intake
losing weight
getting regular exercise
quitting smoking
reducing alcohol consumption
managing stress
Resources
Periodicals
McNamara, Damian. "Obesity Behind Rise in Incidence of Primary Hypertension." Family Practice News April 1, 2003: 45-51.
McNamara, Damian. "Trial Shows Efficacy of Lifestyle Changes for BP: More Intensive Than Typical Office Visit." Family Practice News July 1, 2003: 1-2.
"New BP Guidelines Establish Diagnosis of Pre-hypertension: Level Seeks to Identify At-risk Individuals Early." Case Management Advisor July 2003: S1.
"New Hypertension Guidelines: JNC-7." Clinical Cardiology Alert July 2003: 54-63.
Organizations
American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.
National Heart, Lung and Blood Institute. PO Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.
Texas Heart Institute. Heart Information Service. PO Box 20345, Houston, TX 77225-0345. http://www.tmc.edu/thi.
Key terms
Arteries — Blood vessels that carry blood to organs and other tissues of the body.
Arteriosclerosis — Hardening and thickening of artery walls.
Cushing's syndrome — A disorder in which too much of the adrenal hormone, cortisol, is produced; it may be caused by a pituitary or adrenal gland tumor.
Diastolic blood pressure — Blood pressure when the heart is resting between beats.
Hypertension — High blood pressure.
Renal artery stenosis — Disorder in which the arteries that supply blood to the kidneys constrict.
Sphygmomanometer — An instrument used to measure blood pressure.
Systolic blood pressure — Blood pressure when the heart contracts (beats).
Vasodilator — Any drug that relaxes blood vessel walls.
Ventricle — One of the two lower chambers of the heart.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
hy·per·ten·sion (HTN), (hī'pĕr-ten'shŭn),
High blood pressure; transitory or sustained elevation of systemic arterial blood pressure to a level likely to induce cardiovascular damage or other adverse consequences. Hypertension has been arbitrarily defined as a systolic blood pressure above 140 mmHg or a diastolic blood pressure above 90 mmHg. Consequences of uncontrolled hypertension include retinal vascular damage (Keith-Wagener-Barker changes), cerebrovascular disease and stroke, left ventricular hypertrophy and failure, myocardial infarction, dissecting aneurysm, and renovascular disease. An underlying disorder (for example, renal disease, Cushing syndrome, pheochromocytoma) is identified in fewer than 10% of all cases of hypertension. The remainder, traditionally labeled "essential" hypertension, probably arise from a variety of disturbances in normal pressure-regulating mechanisms (which involve baroreceptors, autonomic influences on the rate and force of cardiac contraction and vascular tone, renal retention of salt and water, formation of angiotensin II under the influence of renin and angiotensin-converting enzyme, and other factors known and unknown), and most are probably genetically conditioned.
Synonym(s): hyperpiesis, hyperpiesia
[hyper- + L. tensio, tension]
Because of its wide prevalence and its impact on cardiovascular health, hypertension is recognized as a major cause of disease and death in industrialized societies. It is estimated that 24% of the U.S. population, including about 50% of all people over age 60, have hypertension, but that only about one third of these are aware of their condition and are under appropriate treatment. People who have normal blood pressure at age 55 still have a 90% lifetime risk of becoming hypertensive. The treatment of this disorder and its complications in the U.S. is estimated to cost $37 billion annually. Hypertension causes 35,000 deaths each year in the U.S., and is a contributing factor in a further 180,000 deaths. It is associated with a threefold increase in the risk of heart attack and a seven to tenfold increase in the risk of stroke. The prevalence of hypertension and the incidence of nonfatal and fatal consequences are substantially higher in African-Americans. Essential hypertension is currently recognized as a group of syndromes, induced by a complex interaction of genetic and environmental factors, which may also include obesity, abnormal glucose and lipid metabolism, insulin resistance, diminished arterial compliance, accelerated atherogenesis, and renal disease. Some features of the hypertensive diathesis (left ventricular hypertrophy, decreased arterial compliance) may occur even before blood pressure measurements detect significant elevation. Although people with extremely high diastolic pressure may experience headache, dizziness, and even encephalopathy, uncomplicated hypertension seldom causes symptoms. Hence the diagnosis of hypertension is usually made by screening apparently healthy people or those under treatment for another condition. Risk factors for hypertension include a family history of the condition, African-American race, advancing age, the postmenopausal state, obesity, obstructive sleep apnea, excessive use of alcohol, sedentary lifestyle, and chronic emotional stress. Treatment options include lifestyle changes (maintenance of healthful weight; a diet low in saturated and total fat and rich in fruits, vegetables, and low-fat dairy products; at least 30 minutes of aerobic exercise several days a week; limitation of sodium intake to 2.4 g daily and of ethanol to 1 oz daily; consumption of adequate potassium, calcium, and magnesium; and avoidance of excessive emotional stress) and a broad range of drugs, including diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor antagonists, α-1 adrenergic antagonists, centrally acting α-agonists, and others. One large study found a thiazide diuretic superior to a calcium channel blocker and an ACE inhibitor in reducing cardiovascular mortality in people with hypertension and one additional cardiovascular risk factor. In recent decades, early detection and aggressive treatment of hypertension have reduced associated morbidity and mortality. Control of hypertension lowers the risk of stroke by 30-50%. Current practice standards call for diligent efforts at prevention through avoidance of known risk factors, particularly in people with a family history of hypertension, and control of cofactors known to increase the risk of cardiovascular damage in people with hypertension (smoking, hypercholesterolemia, diabetes mellitus). Some studies suggest that the goal of treatment should be a diastolic blood pressure of 80 mmHg or lower.
Farlex Partner Medical Dictionary © Farlex 2012
hypertension /hy·per·ten·sion/ (-ten´shun) persistently high arterial blood pressure; it may have no known cause (essential, idiopathic, or primary h.) or may be associated with other diseases (secondary h.) .
accelerated hypertension progressive hypertension with the funduscopic vascular changes of malignant hypertension but without papilledema.
adrenal hypertension that associated with an adrenal tumor which secretes mineralocorticoids.
borderline hypertension a condition in which the arterial blood pressure is sometimes within the normotensive range and sometimes within the hypertensive range.
Goldblatt hypertension that caused experimentally by a Goldblatt kidney.
labile hypertension borderline h.
malignant hypertension a severe hypertensive state with papilledema of the ocular fundus and vascular hemorrhagic lesions, thickening of the small arteries and arterioles, left ventricular hypertrophy, and poor prognosis.
ocular hypertension persistently elevated intraocular pressure in the absence of any other signs of glaucoma; it may or may not progress to chronic simple glaucoma.
portal hypertension abnormally increased pressure in the portal circulation.
pulmonary hypertension abnormally increased pressure in the pulmonary circulation.
renal hypertension that associated with or due to renal disease with a factor of parenchymatous ischemia.
renovascular hypertension that due to occlusive disease of the renal arteries.
systemic venous hypertension elevation of systemic venous pressure, usually detected by inspection of the jugular veins.
Dorland's Medical Dictionary for Health Consumers. © 2007 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
hypertension (hī′pər-tĕn′shən)
n.
1.
a. Abnormally elevated arterial blood pressure.
b. Arterial disease marked by chronic high blood pressure.
2. Elevated pressure or tension of a body fluid, as of the intraocular or cerebrospinal fluids.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
hypertension
[-ten′shən]
Etymology: Gk, hyper + L, tendere, to stretch
a common disorder that is a known cardiovascular disease risk factor, characterized by elevated blood pressure over the normal values of 120/80 mm Hg in an adult over 18 years of age. This elevation in blood pressure can be divided into three classes of hypertension. Prehypertension describes blood pressure measurements of greater than 120 mm Hg systolic or 80 mm Hg diastolic and less than 130 mm Hg systolic or 90 mm Hg diastolic. Persons exhibiting prehypertension are encouraged to explore life-style modifications to lower blood pressure, but blood-pressure lowering agents are not generally prescribed without compelling indications. The second classification of hypertension is Stage 1 hypertension and is defined by a blood pressure of over 130 mm Hg systolic or 90 mm Hg diastolic but less than 160 mm Hg systolic or 100 mm Hg diastolic. Patients with Stage 1 hypertension are also encouraged to make life-style modifications, and initial drug therapy may include thiazide-type diuretics, ACE inhibitors, calcium channel blockers, beta blockers, and angiotensin-receptor blockers, or a combination of these. Stage 2 hypertension is defined by a blood pressure greater than 160 mm Hg systolic or 100 mm Hg diastolic. Persons with Stage 2 hypertension are encouraged to make life-style modifications. Two-drug combination therapies (of thiazide-type diuretics, ACE inhibitors, calcium channel blockers, beta blockers, and angiotensin-receptor blockers) are indicated for these patients. Essential hypertension, the most common kind, has no single identifiable cause, but risk for the disorder is increased by obesity, a high serum sodium level, hypercholesterolemia, and a family history of high blood pressure. Known causes of secondary hypertension include sleep apnea, chronic kidney disease, primary aldosteronism, renovascular disease, chronic steroid therapy, Cushing's syndrome, pheochromocytoma, coarctation of the aorta, and thyroid or parathyroid disease. The incidence of hypertension is higher in men than in women and is twice as great in African-Americans as in Caucasians. People with mild or moderate hypertension may be asymptomatic or may experience suboccipital headaches, especially on rising; tinnitus; lightheadedness; ready fatigability; and palpitations. With sustained hypertension, arterial walls become thickened, inelastic, and resistant to blood flow, and the left ventricle becomes distended and hypertrophied as a result of its efforts to maintain normal circulation against the increased resistance. Inadequate blood supply to the coronary arteries may cause angina or myocardial infarction. Left ventricular hypertrophy may lead to congestive heart failure. Malignant hypertension, characterized by a diastolic pressure higher than 120 mm Hg, severe headaches, blurred vision, and confusion, may result in fatal uremia, myocardial infarction, congestive heart failure, or a cerebrovascular accident. Patients with high blood pressure are advised to follow a low-sodium, low-saturated-fat diet; to control obesity by reducing caloric intake; to exercise; to avoid stress; and to have adequate rest. Also called high blood pressure. See also blood pressure.
enlarge picture
Hypertrophy of the left ventricle in hypertension
Mosby's Medical Dictionary, 9th edition. © 2009, Elsevier.
hypertension High blood pressure Cardiovascular disease An abnormal ↑ systemic arterial pressure, corresponding to a systolic BP of > 160 mm Hg and/or diastolic BP of 95 mm Hg and graded according to intensity of ↑ diastolic BP; HTN affects ± 60 million in the US Workup Evaluation of HTN requires clinical Hx for Pt, family Hx, 2 BP determinations, funduscopy, ID of bruits in neck & abdominal aorta, evaluation of peripheral edema, peripheral pulses and residual neurologic defects in stroke victims, chest films to determine cardiac size and lab parameters to rule out causes of secondary HTN Risk factors Race–blacks more common, ♂, family history of HTN, obesity, defects of lipid metabolism, DM, sedentary lifestyle, cigarette smoking, electrolyte imbalance–eg, ↑ sodium, phosphorus, ↓ potassium, tin Treatment Diet–eg, sodium restriction, ↓ calories, alcohol and cigarettes–the weight gain accompanying smoking cessation tends to offset the minimal ↓ in BP, calcium supplements, lifestyle manipulation–eg, biofeedback, ↑ exercise; antihypertensives–eg, diuretics–benzothiadiazines, loop diuretics, potassium-sparing diuretics, sympatholytic agents–central and peripheral-acting α-adrenergics, β-adrenergics, mixed α- and β-blockers, direct vasodilators, ACE inhibitors–the preferred agent to use ab initio, dihydropiridine CCBs. See ACCT, ACE inhibitor, Borderline hypertension, Borderline isolated systolic hypertension, Calcium channel blocker, Drug-induced hypertension, Essential hypertension, Exercise hypertension, Familial dyslipemic hypertension, Gestational hypertension, Idiopathic intracranial hypertension, Isolated systolic hypertension, Malignant hypertension, MRC, Obetension, Paradoxic hypertension, Pill hypertension, Pregnancy-induced hypertension, Pseudohypertension, Pulmonary hypertension, Refractory hypertension, Renovascular hypertension, SHEP, STOP-Hypertension, TAIM, TOHP-1, TOMHSTyramine hypertension, White coat hypertension.
Hypertension
Class I–mild Diastolic pressure 90-104 mm Hg
Class II–moderate Diastolic pressure 105-119 mm Hg
Class III–severe Diastolic pressure > than 120 mm Hg
Hypertension types
Essential hypertension Idiopathic HTN The major form comprising 90% of all HTN
Malignant hypertension A sustained BP > 200/140 mm Hg, resulting in arteriolar necrosis, most marked in the brain, eg. cerebral hemorrhage, infarcts, and hypertensive encephalopathy, eyes, eg papilledema and hypertensive retinopathy and kidneys, eg acute renal failure and hypertensive nephropathy; if malignant HTN is uncorrected or therapy refractory, Pts may suffer a hypertensive crisis in which prolonged high BP causes left ventricular hypertrophy and CHF
Paroxysmal hypertension Transient or episodic waves of ↑ BP of any etiology, punctuated by periods of normotension, typical of pheochromocytoma
Portal hypertension ↑ portal vein pressure caused by a backflow of blood through splenic arteries, resulting in splenomegaly and collateral circulation, resulting in esophageal varices and/or hemorrhoids; PH may be intra- or extrahepatic, and is often due to cirrhosis, or rarely portal vein disease, venous thrombosis, tumors or abscesses
Pulmonary hypertension A condition defined as a 'wedge' systolic/diastolic pressure > 30/20 mm Hg–Normal: 18-25/12-16 mm Hg, often secondary to blood stasis in peripheral circulation, divided into passive, hyperkinetic, vasoocclusive, vasoconstrictive and secondary forms. See Pulmonary HTN.
Renovascular hypertension see there.
Secondary hypertension
• Aging
• Cardiovascular Open heart surgery, coarctation of aorta, ↑ cardiac output–anemia, thyrotoxicosis, aortic valve insufficiency
• Cerebral ↑ Intracranial pressure
• Endocrine Mineralocorticoid excess, congenital adrenal hyperplasia, glucocorticoid excess, eg Cushing syndrome, hyperparathyroidism, acromegaly
• Gynecologic Pregnancy, oral contraceptives
• Neoplasia Renin-secreting tumors, pheochromocytoma
• ↓ Peripheral vascular resistance AV shunts, Paget's disease of bone, beri-beri
• Renal disease Vascular, parenchymal
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
hy·per·ten·sion (HTN) (hī'pĕr-ten'shŭn)
Persisting high arterial blood pressure; generally established guidelines are values exceeding 140 mmHg systolic or exceeding 90 mmHg diastolic blood pressure. Despite many discrete and inherited but rare forms that have been identified, the evidence is that for the most part blood pressure is a multifactorial, perhaps galtonian, trait. Hypertension is considered a risk factor for developing heart disease, stroke, and kidney disease. Its signs and symptoms include dizziness and headache.
[hyper- + L. tensio, tension]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
hypertension Abnormally high blood pressure. A pressure of 135/85 or less is considered normal. A sustained pressure of 159/99 or over that fails to respond to weight loss, salt reduction, dietary adjustment and smking and stress avoidance, requires drug treatment. Hypertension seldom causes symptoms until an advanced stage is reached in which secondary complications affecting the arteries, kidneys, brain or eyes develop. The condition is, however, potentially dangerous as it can induce a vicious circle of arterial damage resulting in higher blood pressure. Hypertension is a principal cause of STROKE and cardiovascular disease and of DIABETES. Everyone should have regular routine checks of blood pressure. See also KOROTKOFF SOUNDS.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
hypertension abnormally high arterial blood pressure.
Dictionary of Sport and Exercise Science and Medicine by Churchill Livingstone © 2008 Elsevier Limited. All rights reserved.
hypertension persistent raised blood pressure, i.e. >120/80 mmHg (e.g. >150/94 mmHg, recorded over three consecutive occasions)
drug treatment of hypertension Table 1
essential hypertension hypertension without pre-existing renal disease or other known cause
malignant hypertension rapidly progressive, severe hypertension; poor prognosis
Table 1: Drug treatment of hypertension
Drug type Examples Comments
Thiazide diuretics Bendroflumethiazide
Chlortalidone (Hygroton)
Cyclopenthiazide (Navidrex)
Indapamide (Natrilix)
Metolazone (Metenix 5)
Xipamide (Diurexan) Indicated for hypertension in elderly patients
Tend to exacerbate diabetes, gout, systemic lupus erythematosus
May cause postural hypotension
Beta-blockers ('.…lol') Propranolol (Inderal)
Acebutolol (Sectral)
Atenolol (Tenormin)
Bisoprolol (Cardicor)
Carvedilol (Eucardic)
Celiprolol (Celectol)
Esmolol (Brevibloc)
Labetalol (Transdate)
Metoprolol (Betaloc)
Nadolol (Corgard)
Nebivol (Nebilet)
Oxprenolol (Trasicor)
Pindolol (Visken)
Sotalol (Beta-Cardone)
Timolol (Betim) Should not be used by patients with asthma or bradycardia or hypotension
Should be avoided in patients with a history of Raynaud's
May cause distal paraesthesia, impotence, dizziness and exacerbation of psoriasis
Angiotensin-converting enzyme (ACE) inhibitors ('..…pril') Captopril
Cilazapril (Vascace)
Enalapril (Innovace)
Fosinopril (Staril)
Imidapril (Tanatril)
Lisinpril (Carace; Zestril)
Moexipril (Perdix)
Perindopril (Coversyl)
Quinapril (Accupro)
Ramipril (Tritace)
Trandolapril (Gopten) Used only with care in patients taking diuretics, or those with peripheral vascular disease, generalized atherosclerosis and kidney disease
May cause profound hypotension, persistent cough, renal impairment, angioedema and pruritic rashes
Angiotensin II receptor antagonists ('.…sartan') Candesartan (Animax)
Eprosartan (Teveten)
Irbesartan (Aprovel)
Losartan (Cozaar)
Olmesartan (Olmetec)
Telmisartan (Micardis)
Valsartan (Diovan) Used only with caution in patients with aortic or mitral valve stenosis, or renal artery disease
Tend not to be effective in Afro-Caribbean patients with left ventricular hypertrophy
Calcium-channel blockers ('.…dipine') Amlodipine (Istin)
Diltiazem (Calcicard)
Felodipine (Plendil)
Isradipine (Prescal)
Lacidipine (Motens)
Lercadidipine (Zanidip)
Nicardipine (Cardene)
Nifedipine (Adalat)
Nimodipine (Nimotrop)
Nisoldipine (Syscor MR)
Verapamil (Cordilox) May cause abdominal pain, nausea, flushing, oedema, headache, dizziness, constipation and sleep disturbance
Alpha-blockers ('.…zosin') Doxazosin (Cardura)
Indoramin (Baratol)
Prazosin (Hypovase)
Terazosin (Hytrin) Should not be used in patients with urinary incontinence
Tend to cause hypotension, dizziness, vertigo, headache, fatigue
Where antihypertensive drugs are used in combination, a rule-of-thumb guide indicates:
A + C (ACE inhibitors + calcium channel blockers)
B + D (beta-blockers + diuretics)
Illustrated Dictionary of Podiatry and Foot Science by Jean Mooney © 2009 Elsevier Limited. All rights reserved.
hypertension,
n high blood pressure; a condition in which an individual's blood pressure regularly exceeds 140/90 mm Hg. Risk factors include family history of hypertension, excessive alcohol intake, high sodium levels, and obesity.
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Hypertension.
Jonas: Mosby's Dictionary of Complementary and Alternative Medicine. (c) 2005, Elsevier.
hypertension
Abnormally high blood pressure beyond 140-150 mmHg for systolic blood pressure or beyond 90-95 mmHg for diastolic blood pressure. These figures are higher for older people. Elevated blood pressure can give rise to hypertensive retinopathy. See paralysis of the sixth nerve; paralysis of the third nerve; retinal vein occlusion; sphygmomanometer.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
hy·per·ten·sion (HTN) (hī'pĕr-ten'shŭn)
Persisting high arterial blood pressure; generally established guidelines are values exceeding 140 mmHg systolic or exceeding 90 mmHg diastolic blood pressure.
[hyper- + L. tensio, tension]
Medical Dictionary for the Dental Professions © Farlex 2012
hypertension
(hī´purten´shən) (high blood pressure),
n an abnormal elevation of systolic and/or diastolic arterial pressure. Systolic level is generally related to emotional stress, sclerosis of the aorta and large arteries, or aortic insufficiency. Diastolic level may result from obscure causes (essential), renal disease, or endocrine disorders. See also blood pressure.
hypertension, essential,
n a type with an unknown cause.
hypertension, malignant,
n an elevated blood pressure characterized by a progressive course uncontrollable by medication.
hypertension, orthostatic,
n plummeting blood pressure that occurs upon standing up which may be accompanied by dizziness or fainting.
hypertension, portal,
n a type originating in the portal system as occurring in cirrhosis of the liver and other conditions caused by an obstruction of the portal vein.
hypertension pulmonary,
n a type resulting from pulmonary or cardiac disease such as fibrosis of the lung or mitral stenosis.
Mosby's Dental Dictionary, 2nd edition. © 2008 Elsevier, Inc. All rights reserved.
hypertension
persistently high blood pressure. Detected sporadically in animals partly due to the technical difficulties in diagnosis and the lack of recognizable signs. Greyhounds normally have a higher blood pressure than is found in crossbred dogs with features resembling essential hypertension in humans. Secondary hypertension due to advanced renal disease, hyperthyroidism and hyperadrenocorticism does occur in dogs and cats. Temporary episodes of hypertension occur in all animals suffering severe pain, and in horses with acute laminitis.
endocrine hypertension
that occurring in association with diseases of the endocrine glands.
Goldblatt hypertension
see Goldblatt kidney.
inherited hypertension
see rat hypertension (below).
neurogenic hypertension
produced experimentally in laboratory animals by the imposition of surgical and psychological insults on the central nervous system.
ocular hypertension
persistently elevated intraocular pressure in the absence of any other signs of glaucoma; it may or may not progress to chronic simple glaucoma.
portal hypertension
abnormally increased pressure in the portal circulation caused by impedance of blood flow through a diseased liver or portal vein.
pulmonary hypertension
results from high-pressure blood flow from the right ventricle or impedance to blood flow through the lungs or through the left heart. Chronic hypertension causes endothelial degeneration and fibroplasia of vessel walls. The end result may be cor pulmonale or pulmonary edema. See also altitude sickness, cor pulmonale.
rat hypertension
several strains of spontaneously hypertensive rats have been bred.
renal hypertension
secondary hypertension.
systemic venous hypertension
elevation of systemic venous pressure, usually detected by inspection of the jugular veins.
Saunders Comprehensive Veterinary Dictionary, 3 ed. © 2007 Elsevier, Inc. All rights reserved
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Hypertension And High Blood Pressure:
Hypertension is high blood pressure. Blood pressure is the force of blood pushing against the walls of arteries as it flows through them. Arteries are the blood vessels that carry oxygenated blood from the heart to the body's tissues.
Description
As blood flows through arteries it pushes against the inside of the artery walls. The more pressure the blood exerts on the artery walls, the higher the blood pressure will be. The size of small arteries also affects the blood pressure. When the muscular walls of arteries are relaxed, or dilated, the pressure of the blood flowing through them is lower than when the artery walls narrow, or constrict.
Blood pressure is highest when the heart beats to push blood out into the arteries. When the heart relaxes to fill with blood again, the pressure is at its lowest point. Blood pressure when the heart beats is called systolic pressure. Blood pressure when the heart is at rest is called diastolic pressure. When blood pressure is measured, the systolic pressure is stated first and the diastolic pressure second. Blood pressure is measured in millimeters of mercury (mm Hg). For example, if a person's systolic pressure is 120 and diastolic pressure is 80, it is written as 120/80 mm Hg. The American Heart Association has long considred blood pressure less than 140 over 90 normal for adults. However, the National Heart, Lung, and Blood Institute in Bethesda, Maryland released new clinical guidelines for blood pressure in 2003, lowering the standard normal readings. A normal reading was lowered to less than 120 over less than 80.
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Hypertension is a major health problem, especially because it has no symptoms. Many people have hypertension without knowing it. In the United States, about 50 million people age six and older have high blood pressure. Hypertension is more common in men than women and in people over the age of 65 than in younger persons. More than half of all Americans over the age of 65 have hypertension. It also is more common in African-Americans than in white Americans.
Hypertension is serious because people with the condition have a higher risk for heart disease and other medical problems than people with normal blood pressure. Serious complications can be avoided by getting regular blood pressure checks and treating hypertension as soon as it is diagnosed.
If left untreated, hypertension can lead to the following medical conditions:
arteriosclerosis, also called atherosclerosis
heart attack
stroke
enlarged heart
kidney damage.
Arteriosclerosis is hardening of the arteries. The walls of arteries have a layer of muscle and elastic tissue that makes them flexible and able to dilate and constrict as blood flows through them. High blood pressure can make the artery walls thicken and harden. When artery walls thicken, the inside of the blood vessel narrows. Cholesterol and fats are more likely to build up on the walls of damaged arteries, making them even narrower. Blood clots also can get trapped in narrowed arteries, blocking the flow of blood.
Arteries narrowed by arteriosclerosis may not deliver enough blood to organs and other tissues. Reduced or blocked blood flow to the heart can cause a heart attack. If an artery to the brain is blocked, a stroke can result.
Hypertension makes the heart work harder to pump blood through the body. The extra workload can make the heart muscle thicken and stretch. When the heart becomes too enlarged it cannot pump enough blood. If the hypertension is not treated, the heart may fail.
The kidneys remove the body's wastes from the blood. If hypertension thickens the arteries to the kidneys, less waste can be filtered from the blood. As the condition worsens, the kidneys fail and wastes build up in the blood. Dialysis or a kidney transplant are needed when the kidneys fail. About 25% of people who receive kidney dialysis have kidney failure caused by hypertension.
Causes and symptoms
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Many different actions or situations can normally raise blood pressure. Physical activity can temporarily raise blood pressure. Stressful situations can make blood pressure go up. When the stress goes away, blood pressure usually returns to normal. These temporary increases in blood pressure are not considered hypertension. A diagnosis of hypertension is made only when a person has multiple high blood pressure readings over a period of time.
The cause of hypertension is not known in 90 to 95 percent of the people who have it. Hypertension without a known cause is called primary or essential hypertension.
When a person has hypertension caused by another medical condition, it is called secondary hypertension. Secondary hypertension can be caused by a number of different illnesses. Many people with kidney disorders have secondary hypertension. The kidneys regulate the balance of salt and water in the body. If the kidneys cannot rid the body of excess salt and water, blood pressure goes up. Kidney infections, a narrowing of the arteries that carry blood to the kidneys, called renal artery stenosis, and other kidney disorders can disturb the salt and water balance.
Cushing's syndrome and tumors of the pituitary and adrenal glands often increase levels of the adrenal gland hormones cortisol, adrenalin, and aldosterone, which can cause hypertension. Other conditions that can cause hypertension are blood vessel diseases, thyroid gland disorders, some prescribed drugs, alcoholism, and pregnancy.
Even though the cause of most hypertension is not known, some people have risk factors that give them a greater chance of getting hypertension. Many of these risk factors can be changed to lower the chance of developing hypertension or as part of a treatment program to lower blood pressure.
Risk factors for hypertension include:
age over 60
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male sex
race
heredity
salt sensitivity
obesity
inactive lifestyle
heavy alcohol consumption
use of oral contraceptives
Some risk factors for getting hypertension can be changed, while others cannot. Age, male sex, and race are risk factors that a person can't do anything about. Some people inherit a tendency to get hypertension. People with family members who have hypertension are more likely to develop it than those whose relatives are not hypertensive. People with these risk factors can avoid or eliminate the other risk factors to lower their chance of developing hypertension. A 2003 report found that the rise in incidence of high blood pressure among children is most likely due to an increase in the number of overweight and obese children and adolescents.
Diagnosis
Because hypertension doesn't cause symptoms, it is important to have blood pressure checked regularly. Blood pressure is measured with an instrument called a sphygmomanometer. A cloth-covered rubber cuff is wrapped around the upper arm and inflated. When the cuff is inflated, an artery in the arm is squeezed to momentarily stop the flow of blood. Then, the air is let out of the cuff while a stethoscope placed over the artery is used to detect the sound of the blood spurting back through the artery. This first sound is the systolic pressure, the pressure when the heart beats. The last sound heard as the rest of the air is released is the diastolic pressure, the pressure between heart beats. Both sounds are recorded on the mercury gauge on the sphygmomanometer.
Normal blood pressure is defined by a range of values. Blood pressure lower than 120/80 mm Hg is considered normal. A number of factors such as pain, stress or anxiety can cause a temporary increase in blood pressure. For this reason, hypertension is not diagnosed on one high blood pressure reading. If a blood pressure reading is 120/80 or higher for the first time, the physician will have the person return for another blood pressure check. Diagnosis of hypertension usually is made based on
two or more readings after the first visit.
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Systolic hypertension of the elderly is common and is diagnosed when the diastolic pressure is normal or low, but the systolic is elevated, e.g.170/70 mm Hg. This condition usually co-exists with hardening of the arteries (atherosclerosis).
Blood pressure measurements are classified in stages, according to severity:
normal blood pressure: less than less than 120/80 mm Hg
pre-hypertension: 120-129/80-89 mm Hg
Stage 1 hypertension: 140-159/90-99 mm Hg
Stage 2 hypertension: at or greater than 160-179/100-109 mm Hg
A typical physical examination to evaluate hypertension includes:
medical and family history
physical examination
ophthalmoscopy: Examination of the blood vessels in the eye
chest x ray
electrocardiograph (ECG)
blood and urine tests.
The medical and family history help the physician determine if the patient has any conditions or disorders that might contribute to or cause the hypertension. A family history of hypertension might suggest a genetic predisposition for hypertension.
The physical exam may include several blood pressure readings at different times and in different positions. The physician uses a stethoscope to listen to sounds made by the heart and blood flowing through the arteries. The pulse, reflexes, and height and weight are checked and recorded. Internal organs are palpated, or felt, to determine if they are enlarged.
Because hypertension can cause damage to the blood vessels in the eyes, the eyes may be checked with a instrument called an ophthalmoscope. The physician will look for thickening, narrowing, or hemorrhages in the blood vessels.
A chest x ray can detect an enlarged heart, other vascular (heart) abnormalities, or lung disease.
An electrocardiogram (ECG) measures the electrical activity of the heart. It can detect if the heart muscle is enlarged and if there is damage to the heart muscle from blocked arteries.
Urine and blood tests may be done to evaluate health and to detect the presence of disorders that might cause hypertension.
Treatment
There is no cure for primary hypertension, but blood pressure can almost always be lowered with the correct treatment. The goal of treatment is to lower blood pressure to levels that will prevent heart disease and other complications of hypertension. In secondary hypertension, the disease that is responsible for the hypertension is treated in addition to the hypertension itself. Successful treatment of the underlying disorder may cure the secondary hypertension.
Guidelines advise that clinicians work with patients to agree on blood pressure goals and develop a treatment plan for the individual patient. Actual combinations of medications and lifestyle changes will vary from one person to the next. Treatment to lower blood pressure may include changes in diet, getting regular exercise, and taking antihypertensive medications. Patients falling into the pre-hypertension range who don't have damage to the heart or kidneys often are advised to make needed lifestyle changes only. A 2003 report of a clinical trial showed that adults with elevated blood pressures lowered them as mush as 38% by making lifestyle changes and participating in the DASH diet, which encourages eating more fruit and vegetables.
Lifestyle changes that may reduce blood pressure by about 5 to 10 mm Hg include:
reducing salt intake
reducing fat intake
losing weight
getting regular exercise
quitting smoking
reducing alcohol consumption
managing stress
Patients whose blood pressure falls into the Stage 1 hypertension range may be advised to take antihypertensive medication. Numerous drugs have been developed to treat hypertension. The choice of medication will depend on the stage of hypertension, side effects, other medical conditions the patient may have, and other medicines the patient is taking.
If treatment with a single medicine fails to lower blood pressure enough, a different medicine may be tried or another medicine may be added to the first. Patients with more severe hypertension may initially be given a combination of medicines to control their hypertension. Combining antihypertensive medicines with different types of action often controls blood pressure with smaller doses of each drug than would be needed for just one.
Antihypertensive medicines fall into several classes of drugs:
diuretics
beta-blockers
calcium channel blockers
angiotensin converting enzyme inhibitors (ACE inhibitors)
alpha-blockers
alpha-beta blockers
vasodilators
peripheral acting adrenergic antagonists
centrally acting agonists
Diuretics help the kidneys eliminate excess salt and water from the body's tissues and the blood. This helps reduce the swelling caused by fluid buildup in the tissues. The reduction of fluid dilates the walls of arteries and lowers blood pressure. New guidelines released in 2003 suggest diuretics as the first drug of choice for most patients with high blood pressure and as part of any multi-drug combination.
Beta-blockers lower blood pressure by acting on the nervous system to slow the heart rate and reduce the force of the heart's contraction. They are used with caution in patients with heart failure, asthma, diabetes, or circulation problems in the hands and feet.
Calcium channel blockers block the entry of calcium into muscle cells in artery walls. Muscle cells need calcium to constrict, so reducing their calcium keeps them more relaxed and lowers blood pressure.
ACE inhibitors block the production of substances that constrict blood vessels. They also help reduce the build-up of water and salt in the tissues. They often are given to patients with heart failure, kidney disease, or diabetes. ACE inhibitors may be used together with diuretics.
Alpha-blockers act on the nervous system to dilate arteries and reduce the force of the heart's contractions.
Alpha-beta blockers combine the actions of alpha and beta blockers.
Vasodilators act directly on arteries to relax their walls so blood can move more easily through them. They lower blood pressure rapidly and are injected in hypertensive emergencies when patients have dangerously high blood pressure.
Peripheral acting adrenergic antagonists act on the nervous system to relax arteries and reduce the force of the heart's contractions. They usually are prescribed together with a diuretic. Peripheral acting adrenergic antagonists can cause slowed mental function and lethargy.
Centrally acting agonists also act on the nervous system to relax arteries and slow the heart rate. They are usually used with other antihypertensive medicines.
Prognosis
There is no cure for hypertension. However, it can be well controlled with the proper treatment. Therapy with a combination of lifestyle changes and antihypertensive medicines usually can keep blood pressure at levels that will not cause damage to the heart or other organs. The key to avoiding serious complications of hypertension is to detect and treat it before damage occurs. Because antihypertensive medicines control blood pressure, but do not cure it, patients must continue taking the medications to maintain reduced blood pressure levels and avoid complications.
Prevention
Prevention of hypertension centers on avoiding or eliminating known risk factors. Even persons at risk because of age, race, or sex or those who have an inherited risk can lower their chance of developing hypertension.
The risk of developing hypertension can be reduced by making the same changes recommended for treating hypertension:
reducing salt intake
reducing fat intake
losing weight
getting regular exercise
quitting smoking
reducing alcohol consumption
managing stress
Resources
Periodicals
McNamara, Damian. "Obesity Behind Rise in Incidence of Primary Hypertension." Family Practice News April 1, 2003: 45-51.
McNamara, Damian. "Trial Shows Efficacy of Lifestyle Changes for BP: More Intensive Than Typical Office Visit." Family Practice News July 1, 2003: 1-2.
"New BP Guidelines Establish Diagnosis of Pre-hypertension: Level Seeks to Identify At-risk Individuals Early." Case Management Advisor July 2003: S1.
"New Hypertension Guidelines: JNC-7." Clinical Cardiology Alert July 2003: 54-63.
Organizations
American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.
National Heart, Lung and Blood Institute. PO Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.
Texas Heart Institute. Heart Information Service. PO Box 20345, Houston, TX 77225-0345. http://www.tmc.edu/thi.
Key terms
Arteries — Blood vessels that carry blood to organs and other tissues of the body.
Arteriosclerosis — Hardening and thickening of artery walls.
Cushing's syndrome — A disorder in which too much of the adrenal hormone, cortisol, is produced; it may be caused by a pituitary or adrenal gland tumor.
Diastolic blood pressure — Blood pressure when the heart is resting between beats.
Hypertension — High blood pressure.
Renal artery stenosis — Disorder in which the arteries that supply blood to the kidneys constrict.
Sphygmomanometer — An instrument used to measure blood pressure.
Systolic blood pressure — Blood pressure when the heart contracts (beats).
Vasodilator — Any drug that relaxes blood vessel walls.
Ventricle — One of the two lower chambers of the heart.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
hy·per·ten·sion (HTN), (hī'pĕr-ten'shŭn),
High blood pressure; transitory or sustained elevation of systemic arterial blood pressure to a level likely to induce cardiovascular damage or other adverse consequences. Hypertension has been arbitrarily defined as a systolic blood pressure above 140 mmHg or a diastolic blood pressure above 90 mmHg. Consequences of uncontrolled hypertension include retinal vascular damage (Keith-Wagener-Barker changes), cerebrovascular disease and stroke, left ventricular hypertrophy and failure, myocardial infarction, dissecting aneurysm, and renovascular disease. An underlying disorder (for example, renal disease, Cushing syndrome, pheochromocytoma) is identified in fewer than 10% of all cases of hypertension. The remainder, traditionally labeled "essential" hypertension, probably arise from a variety of disturbances in normal pressure-regulating mechanisms (which involve baroreceptors, autonomic influences on the rate and force of cardiac contraction and vascular tone, renal retention of salt and water, formation of angiotensin II under the influence of renin and angiotensin-converting enzyme, and other factors known and unknown), and most are probably genetically conditioned.
Synonym(s): hyperpiesis, hyperpiesia
[hyper- + L. tensio, tension]
Because of its wide prevalence and its impact on cardiovascular health, hypertension is recognized as a major cause of disease and death in industrialized societies. It is estimated that 24% of the U.S. population, including about 50% of all people over age 60, have hypertension, but that only about one third of these are aware of their condition and are under appropriate treatment. People who have normal blood pressure at age 55 still have a 90% lifetime risk of becoming hypertensive. The treatment of this disorder and its complications in the U.S. is estimated to cost $37 billion annually. Hypertension causes 35,000 deaths each year in the U.S., and is a contributing factor in a further 180,000 deaths. It is associated with a threefold increase in the risk of heart attack and a seven to tenfold increase in the risk of stroke. The prevalence of hypertension and the incidence of nonfatal and fatal consequences are substantially higher in African-Americans. Essential hypertension is currently recognized as a group of syndromes, induced by a complex interaction of genetic and environmental factors, which may also include obesity, abnormal glucose and lipid metabolism, insulin resistance, diminished arterial compliance, accelerated atherogenesis, and renal disease. Some features of the hypertensive diathesis (left ventricular hypertrophy, decreased arterial compliance) may occur even before blood pressure measurements detect significant elevation. Although people with extremely high diastolic pressure may experience headache, dizziness, and even encephalopathy, uncomplicated hypertension seldom causes symptoms. Hence the diagnosis of hypertension is usually made by screening apparently healthy people or those under treatment for another condition. Risk factors for hypertension include a family history of the condition, African-American race, advancing age, the postmenopausal state, obesity, obstructive sleep apnea, excessive use of alcohol, sedentary lifestyle, and chronic emotional stress. Treatment options include lifestyle changes (maintenance of healthful weight; a diet low in saturated and total fat and rich in fruits, vegetables, and low-fat dairy products; at least 30 minutes of aerobic exercise several days a week; limitation of sodium intake to 2.4 g daily and of ethanol to 1 oz daily; consumption of adequate potassium, calcium, and magnesium; and avoidance of excessive emotional stress) and a broad range of drugs, including diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor antagonists, α-1 adrenergic antagonists, centrally acting α-agonists, and others. One large study found a thiazide diuretic superior to a calcium channel blocker and an ACE inhibitor in reducing cardiovascular mortality in people with hypertension and one additional cardiovascular risk factor. In recent decades, early detection and aggressive treatment of hypertension have reduced associated morbidity and mortality. Control of hypertension lowers the risk of stroke by 30-50%. Current practice standards call for diligent efforts at prevention through avoidance of known risk factors, particularly in people with a family history of hypertension, and control of cofactors known to increase the risk of cardiovascular damage in people with hypertension (smoking, hypercholesterolemia, diabetes mellitus). Some studies suggest that the goal of treatment should be a diastolic blood pressure of 80 mmHg or lower.
Farlex Partner Medical Dictionary © Farlex 2012
hypertension /hy·per·ten·sion/ (-ten´shun) persistently high arterial blood pressure; it may have no known cause (essential, idiopathic, or primary h.) or may be associated with other diseases (secondary h.) .
accelerated hypertension progressive hypertension with the funduscopic vascular changes of malignant hypertension but without papilledema.
adrenal hypertension that associated with an adrenal tumor which secretes mineralocorticoids.
borderline hypertension a condition in which the arterial blood pressure is sometimes within the normotensive range and sometimes within the hypertensive range.
Goldblatt hypertension that caused experimentally by a Goldblatt kidney.
labile hypertension borderline h.
malignant hypertension a severe hypertensive state with papilledema of the ocular fundus and vascular hemorrhagic lesions, thickening of the small arteries and arterioles, left ventricular hypertrophy, and poor prognosis.
ocular hypertension persistently elevated intraocular pressure in the absence of any other signs of glaucoma; it may or may not progress to chronic simple glaucoma.
portal hypertension abnormally increased pressure in the portal circulation.
pulmonary hypertension abnormally increased pressure in the pulmonary circulation.
renal hypertension that associated with or due to renal disease with a factor of parenchymatous ischemia.
renovascular hypertension that due to occlusive disease of the renal arteries.
systemic venous hypertension elevation of systemic venous pressure, usually detected by inspection of the jugular veins.
Dorland's Medical Dictionary for Health Consumers. © 2007 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
hypertension (hī′pər-tĕn′shən)
n.
1.
a. Abnormally elevated arterial blood pressure.
b. Arterial disease marked by chronic high blood pressure.
2. Elevated pressure or tension of a body fluid, as of the intraocular or cerebrospinal fluids.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
hypertension
[-ten′shən]
Etymology: Gk, hyper + L, tendere, to stretch
a common disorder that is a known cardiovascular disease risk factor, characterized by elevated blood pressure over the normal values of 120/80 mm Hg in an adult over 18 years of age. This elevation in blood pressure can be divided into three classes of hypertension. Prehypertension describes blood pressure measurements of greater than 120 mm Hg systolic or 80 mm Hg diastolic and less than 130 mm Hg systolic or 90 mm Hg diastolic. Persons exhibiting prehypertension are encouraged to explore life-style modifications to lower blood pressure, but blood-pressure lowering agents are not generally prescribed without compelling indications. The second classification of hypertension is Stage 1 hypertension and is defined by a blood pressure of over 130 mm Hg systolic or 90 mm Hg diastolic but less than 160 mm Hg systolic or 100 mm Hg diastolic. Patients with Stage 1 hypertension are also encouraged to make life-style modifications, and initial drug therapy may include thiazide-type diuretics, ACE inhibitors, calcium channel blockers, beta blockers, and angiotensin-receptor blockers, or a combination of these. Stage 2 hypertension is defined by a blood pressure greater than 160 mm Hg systolic or 100 mm Hg diastolic. Persons with Stage 2 hypertension are encouraged to make life-style modifications. Two-drug combination therapies (of thiazide-type diuretics, ACE inhibitors, calcium channel blockers, beta blockers, and angiotensin-receptor blockers) are indicated for these patients. Essential hypertension, the most common kind, has no single identifiable cause, but risk for the disorder is increased by obesity, a high serum sodium level, hypercholesterolemia, and a family history of high blood pressure. Known causes of secondary hypertension include sleep apnea, chronic kidney disease, primary aldosteronism, renovascular disease, chronic steroid therapy, Cushing's syndrome, pheochromocytoma, coarctation of the aorta, and thyroid or parathyroid disease. The incidence of hypertension is higher in men than in women and is twice as great in African-Americans as in Caucasians. People with mild or moderate hypertension may be asymptomatic or may experience suboccipital headaches, especially on rising; tinnitus; lightheadedness; ready fatigability; and palpitations. With sustained hypertension, arterial walls become thickened, inelastic, and resistant to blood flow, and the left ventricle becomes distended and hypertrophied as a result of its efforts to maintain normal circulation against the increased resistance. Inadequate blood supply to the coronary arteries may cause angina or myocardial infarction. Left ventricular hypertrophy may lead to congestive heart failure. Malignant hypertension, characterized by a diastolic pressure higher than 120 mm Hg, severe headaches, blurred vision, and confusion, may result in fatal uremia, myocardial infarction, congestive heart failure, or a cerebrovascular accident. Patients with high blood pressure are advised to follow a low-sodium, low-saturated-fat diet; to control obesity by reducing caloric intake; to exercise; to avoid stress; and to have adequate rest. Also called high blood pressure. See also blood pressure.
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Hypertrophy of the left ventricle in hypertension
Mosby's Medical Dictionary, 9th edition. © 2009, Elsevier.
hypertension High blood pressure Cardiovascular disease An abnormal ↑ systemic arterial pressure, corresponding to a systolic BP of > 160 mm Hg and/or diastolic BP of 95 mm Hg and graded according to intensity of ↑ diastolic BP; HTN affects ± 60 million in the US Workup Evaluation of HTN requires clinical Hx for Pt, family Hx, 2 BP determinations, funduscopy, ID of bruits in neck & abdominal aorta, evaluation of peripheral edema, peripheral pulses and residual neurologic defects in stroke victims, chest films to determine cardiac size and lab parameters to rule out causes of secondary HTN Risk factors Race–blacks more common, ♂, family history of HTN, obesity, defects of lipid metabolism, DM, sedentary lifestyle, cigarette smoking, electrolyte imbalance–eg, ↑ sodium, phosphorus, ↓ potassium, tin Treatment Diet–eg, sodium restriction, ↓ calories, alcohol and cigarettes–the weight gain accompanying smoking cessation tends to offset the minimal ↓ in BP, calcium supplements, lifestyle manipulation–eg, biofeedback, ↑ exercise; antihypertensives–eg, diuretics–benzothiadiazines, loop diuretics, potassium-sparing diuretics, sympatholytic agents–central and peripheral-acting α-adrenergics, β-adrenergics, mixed α- and β-blockers, direct vasodilators, ACE inhibitors–the preferred agent to use ab initio, dihydropiridine CCBs. See ACCT, ACE inhibitor, Borderline hypertension, Borderline isolated systolic hypertension, Calcium channel blocker, Drug-induced hypertension, Essential hypertension, Exercise hypertension, Familial dyslipemic hypertension, Gestational hypertension, Idiopathic intracranial hypertension, Isolated systolic hypertension, Malignant hypertension, MRC, Obetension, Paradoxic hypertension, Pill hypertension, Pregnancy-induced hypertension, Pseudohypertension, Pulmonary hypertension, Refractory hypertension, Renovascular hypertension, SHEP, STOP-Hypertension, TAIM, TOHP-1, TOMHSTyramine hypertension, White coat hypertension.
Hypertension
Class I–mild Diastolic pressure 90-104 mm Hg
Class II–moderate Diastolic pressure 105-119 mm Hg
Class III–severe Diastolic pressure > than 120 mm Hg
Hypertension types
Essential hypertension Idiopathic HTN The major form comprising 90% of all HTN
Malignant hypertension A sustained BP > 200/140 mm Hg, resulting in arteriolar necrosis, most marked in the brain, eg. cerebral hemorrhage, infarcts, and hypertensive encephalopathy, eyes, eg papilledema and hypertensive retinopathy and kidneys, eg acute renal failure and hypertensive nephropathy; if malignant HTN is uncorrected or therapy refractory, Pts may suffer a hypertensive crisis in which prolonged high BP causes left ventricular hypertrophy and CHF
Paroxysmal hypertension Transient or episodic waves of ↑ BP of any etiology, punctuated by periods of normotension, typical of pheochromocytoma
Portal hypertension ↑ portal vein pressure caused by a backflow of blood through splenic arteries, resulting in splenomegaly and collateral circulation, resulting in esophageal varices and/or hemorrhoids; PH may be intra- or extrahepatic, and is often due to cirrhosis, or rarely portal vein disease, venous thrombosis, tumors or abscesses
Pulmonary hypertension A condition defined as a 'wedge' systolic/diastolic pressure > 30/20 mm Hg–Normal: 18-25/12-16 mm Hg, often secondary to blood stasis in peripheral circulation, divided into passive, hyperkinetic, vasoocclusive, vasoconstrictive and secondary forms. See Pulmonary HTN.
Renovascular hypertension see there.
Secondary hypertension
• Aging
• Cardiovascular Open heart surgery, coarctation of aorta, ↑ cardiac output–anemia, thyrotoxicosis, aortic valve insufficiency
• Cerebral ↑ Intracranial pressure
• Endocrine Mineralocorticoid excess, congenital adrenal hyperplasia, glucocorticoid excess, eg Cushing syndrome, hyperparathyroidism, acromegaly
• Gynecologic Pregnancy, oral contraceptives
• Neoplasia Renin-secreting tumors, pheochromocytoma
• ↓ Peripheral vascular resistance AV shunts, Paget's disease of bone, beri-beri
• Renal disease Vascular, parenchymal
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
hy·per·ten·sion (HTN) (hī'pĕr-ten'shŭn)
Persisting high arterial blood pressure; generally established guidelines are values exceeding 140 mmHg systolic or exceeding 90 mmHg diastolic blood pressure. Despite many discrete and inherited but rare forms that have been identified, the evidence is that for the most part blood pressure is a multifactorial, perhaps galtonian, trait. Hypertension is considered a risk factor for developing heart disease, stroke, and kidney disease. Its signs and symptoms include dizziness and headache.
[hyper- + L. tensio, tension]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
hypertension Abnormally high blood pressure. A pressure of 135/85 or less is considered normal. A sustained pressure of 159/99 or over that fails to respond to weight loss, salt reduction, dietary adjustment and smking and stress avoidance, requires drug treatment. Hypertension seldom causes symptoms until an advanced stage is reached in which secondary complications affecting the arteries, kidneys, brain or eyes develop. The condition is, however, potentially dangerous as it can induce a vicious circle of arterial damage resulting in higher blood pressure. Hypertension is a principal cause of STROKE and cardiovascular disease and of DIABETES. Everyone should have regular routine checks of blood pressure. See also KOROTKOFF SOUNDS.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
hypertension abnormally high arterial blood pressure.
Dictionary of Sport and Exercise Science and Medicine by Churchill Livingstone © 2008 Elsevier Limited. All rights reserved.
hypertension persistent raised blood pressure, i.e. >120/80 mmHg (e.g. >150/94 mmHg, recorded over three consecutive occasions)
drug treatment of hypertension Table 1
essential hypertension hypertension without pre-existing renal disease or other known cause
malignant hypertension rapidly progressive, severe hypertension; poor prognosis
Table 1: Drug treatment of hypertension
Drug type Examples Comments
Thiazide diuretics Bendroflumethiazide
Chlortalidone (Hygroton)
Cyclopenthiazide (Navidrex)
Indapamide (Natrilix)
Metolazone (Metenix 5)
Xipamide (Diurexan) Indicated for hypertension in elderly patients
Tend to exacerbate diabetes, gout, systemic lupus erythematosus
May cause postural hypotension
Beta-blockers ('.…lol') Propranolol (Inderal)
Acebutolol (Sectral)
Atenolol (Tenormin)
Bisoprolol (Cardicor)
Carvedilol (Eucardic)
Celiprolol (Celectol)
Esmolol (Brevibloc)
Labetalol (Transdate)
Metoprolol (Betaloc)
Nadolol (Corgard)
Nebivol (Nebilet)
Oxprenolol (Trasicor)
Pindolol (Visken)
Sotalol (Beta-Cardone)
Timolol (Betim) Should not be used by patients with asthma or bradycardia or hypotension
Should be avoided in patients with a history of Raynaud's
May cause distal paraesthesia, impotence, dizziness and exacerbation of psoriasis
Angiotensin-converting enzyme (ACE) inhibitors ('..…pril') Captopril
Cilazapril (Vascace)
Enalapril (Innovace)
Fosinopril (Staril)
Imidapril (Tanatril)
Lisinpril (Carace; Zestril)
Moexipril (Perdix)
Perindopril (Coversyl)
Quinapril (Accupro)
Ramipril (Tritace)
Trandolapril (Gopten) Used only with care in patients taking diuretics, or those with peripheral vascular disease, generalized atherosclerosis and kidney disease
May cause profound hypotension, persistent cough, renal impairment, angioedema and pruritic rashes
Angiotensin II receptor antagonists ('.…sartan') Candesartan (Animax)
Eprosartan (Teveten)
Irbesartan (Aprovel)
Losartan (Cozaar)
Olmesartan (Olmetec)
Telmisartan (Micardis)
Valsartan (Diovan) Used only with caution in patients with aortic or mitral valve stenosis, or renal artery disease
Tend not to be effective in Afro-Caribbean patients with left ventricular hypertrophy
Calcium-channel blockers ('.…dipine') Amlodipine (Istin)
Diltiazem (Calcicard)
Felodipine (Plendil)
Isradipine (Prescal)
Lacidipine (Motens)
Lercadidipine (Zanidip)
Nicardipine (Cardene)
Nifedipine (Adalat)
Nimodipine (Nimotrop)
Nisoldipine (Syscor MR)
Verapamil (Cordilox) May cause abdominal pain, nausea, flushing, oedema, headache, dizziness, constipation and sleep disturbance
Alpha-blockers ('.…zosin') Doxazosin (Cardura)
Indoramin (Baratol)
Prazosin (Hypovase)
Terazosin (Hytrin) Should not be used in patients with urinary incontinence
Tend to cause hypotension, dizziness, vertigo, headache, fatigue
Where antihypertensive drugs are used in combination, a rule-of-thumb guide indicates:
A + C (ACE inhibitors + calcium channel blockers)
B + D (beta-blockers + diuretics)
Illustrated Dictionary of Podiatry and Foot Science by Jean Mooney © 2009 Elsevier Limited. All rights reserved.
hypertension,
n high blood pressure; a condition in which an individual's blood pressure regularly exceeds 140/90 mm Hg. Risk factors include family history of hypertension, excessive alcohol intake, high sodium levels, and obesity.
Enlarge picture
Hypertension.
Jonas: Mosby's Dictionary of Complementary and Alternative Medicine. (c) 2005, Elsevier.
hypertension
Abnormally high blood pressure beyond 140-150 mmHg for systolic blood pressure or beyond 90-95 mmHg for diastolic blood pressure. These figures are higher for older people. Elevated blood pressure can give rise to hypertensive retinopathy. See paralysis of the sixth nerve; paralysis of the third nerve; retinal vein occlusion; sphygmomanometer.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
hy·per·ten·sion (HTN) (hī'pĕr-ten'shŭn)
Persisting high arterial blood pressure; generally established guidelines are values exceeding 140 mmHg systolic or exceeding 90 mmHg diastolic blood pressure.
[hyper- + L. tensio, tension]
Medical Dictionary for the Dental Professions © Farlex 2012
hypertension
(hī´purten´shən) (high blood pressure),
n an abnormal elevation of systolic and/or diastolic arterial pressure. Systolic level is generally related to emotional stress, sclerosis of the aorta and large arteries, or aortic insufficiency. Diastolic level may result from obscure causes (essential), renal disease, or endocrine disorders. See also blood pressure.
hypertension, essential,
n a type with an unknown cause.
hypertension, malignant,
n an elevated blood pressure characterized by a progressive course uncontrollable by medication.
hypertension, orthostatic,
n plummeting blood pressure that occurs upon standing up which may be accompanied by dizziness or fainting.
hypertension, portal,
n a type originating in the portal system as occurring in cirrhosis of the liver and other conditions caused by an obstruction of the portal vein.
hypertension pulmonary,
n a type resulting from pulmonary or cardiac disease such as fibrosis of the lung or mitral stenosis.
Mosby's Dental Dictionary, 2nd edition. © 2008 Elsevier, Inc. All rights reserved.
hypertension
persistently high blood pressure. Detected sporadically in animals partly due to the technical difficulties in diagnosis and the lack of recognizable signs. Greyhounds normally have a higher blood pressure than is found in crossbred dogs with features resembling essential hypertension in humans. Secondary hypertension due to advanced renal disease, hyperthyroidism and hyperadrenocorticism does occur in dogs and cats. Temporary episodes of hypertension occur in all animals suffering severe pain, and in horses with acute laminitis.
endocrine hypertension
that occurring in association with diseases of the endocrine glands.
Goldblatt hypertension
see Goldblatt kidney.
inherited hypertension
see rat hypertension (below).
neurogenic hypertension
produced experimentally in laboratory animals by the imposition of surgical and psychological insults on the central nervous system.
ocular hypertension
persistently elevated intraocular pressure in the absence of any other signs of glaucoma; it may or may not progress to chronic simple glaucoma.
portal hypertension
abnormally increased pressure in the portal circulation caused by impedance of blood flow through a diseased liver or portal vein.
pulmonary hypertension
results from high-pressure blood flow from the right ventricle or impedance to blood flow through the lungs or through the left heart. Chronic hypertension causes endothelial degeneration and fibroplasia of vessel walls. The end result may be cor pulmonale or pulmonary edema. See also altitude sickness, cor pulmonale.
rat hypertension
several strains of spontaneously hypertensive rats have been bred.
renal hypertension
secondary hypertension.
systemic venous hypertension
elevation of systemic venous pressure, usually detected by inspection of the jugular veins.
Saunders Comprehensive Veterinary Dictionary, 3 ed. © 2007 Elsevier, Inc. All rights reserved
