Hypertension

high blood pressure; transitory or sustained elevation of systemic arterial blood pressure to a level likely to induce cardiovascular damage or other adverse consequences

Description
Hypertension has been arbitrarily defined as a systolic blood pressure above 140 mm Hg or a diastolic blood pressure above 90 mm Hg. 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 (e.g., 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. Syn hyperpiesis, hyperpiesia

Because of its wide prevalence and its impact on cardiovascular health, hypertension is a major cause of disease and death in industrialized societies. It is estimated that 50–70 million Americans, 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. Hypertension causes 35,000 deaths annually in the U.S., and is a contributing factor in a further 180,000 deaths. It is associated with a 3-fold increase in the risk of heart attack and a 7- to 10-fold increase in the risk of stroke. The prevalence of hypertension and the incidence of nonfatal and fatal consequences are substantially higher in African-Americans. 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 persons or those under treatment for another condition. Risk factors for hypertension include a family history of hypertension, African-American race, advancing age, the postmenopausal state, excessive dietary sodium, obesity, excessive use of alcohol, sedentary lifestyle, and chronic emotional stress.

Treatment options include lifestyle changes (maintenance of healthful weight; 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, &#946;-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, angiotensin II receptor antagonists, 1-adrenergic antagonists, centrally acting &#945;-agonists, and others. In recent decades, early detection and aggressive treatment of hypertension have reduced associated morbidity and mortality. Current practice standards call for still more diligent management, including prevention through avoidance of known risk factors, particularly in persons with a family history of hypertension, and control of cofactors known to increase the risk of cardiovascular damage in persons 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. In patients with sickle cell disease, a systolic pressure of 130 mmHg is thought to represent relative hypertension and must be prudently lowered, not less than 110 mmHg though, and not by restricting the intake of salt.