Sunday, January 15, 2006

hypertension (high blood pressure)

Hypertension is increased vascular resistance, especially in the arterioles and small muscular arteries. Hypertension may be associated with Cushing syndrome (excessive secretion of adrenal cortical hormones), hyperthyroidism, coarctation of the aorta (constriction of the major channel of the arterial trunk), pheochromocytoma (encapsulated vascular tumor of the inner portion of the kidney), renal failure, increased intracranial pressure, and hyperaldosteronism (abnormality of electrolyte metabolism causing water retention). The most common type is essential hypertension in which the exact cause is unknown.
Hypertension occurs in 20 percent to 33 percent of the population over age 55, peaking at 55 to 64 years of age. The symptoms of hypertension may include headache and palpitation, but more likely the person is asymptomatic. Hypertension is characterized by a sustained elevation in arterial pressure, but the systolic, diastolic, and mean arterial pressure may all be elevated. Ventricle hypertrophy, congestive heart failure, and strokes may be consequences of undetected or poorly controlled hypertension. A diagnostic workup is important to determine the cause of the hypertension. Finding the exact cause allows more accurate treatment. The treatment for hypertensive patients consists of four classes of drugs:
1. Diuretics--drugs that have a compensatory increased renin activity, presumably causing a depletion of intravascular fluid volume
2. Sympatholytics--drugs that decrease sympathetic nervous system activity often leading to an increase in intravascular fluid volume
3. Vasodilators--drugs that produce tachycardia, which can offset the blood pressure lowering effects of the other drugs
4. Beta blockers
With all the effects of these drugs, a combination of drug therapy permits the greatest therapeutic effects with lowered doses of any one drug, thus decreasing the chance or likelihood of dose-related side effects. Placing the patient on a weight-reduction and low-sodium diet lowered the blood pressure in a number of patients. As little as a 10-pound weight loss can lower the pressure to a normal level in some cases.
Scherer, J. C. Introductory Medical Surgical Nursing, 3rd ed. Philadelphia: J. B. Lippincott Co., 1982.
Steinberg, F. U. Care of the Geriatric Patient, 6th ed. St. Louis: C. V. Mosby Co., 1983.

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