Hypertension
I. Measurement of Blood Pressure
II. How High Is High?
III. Causes of Hypertension
IV. Pathogenesis of Primary Essential Hypertension
V. Complications
VI. Symptoms
VII. Investigations
VIII. Nondrug Treatment
IX. Drug Treatment
GLOSSARY
afterload arterial impedance, restriction to blood flow delivered
from the left ventricle; force against which the myocardium
contracts in systole; a major determinant of ventricular wall
stress. atherosclerosis same as atheroma, raised plaques filled with
cholesterol, calcium, and other substances on the inner wall
of arteries that obstruct the lumen and the flow of blood;
the plaque of atheroma hardens the artery, hence, the term
atherosclerosis (sclerosis ¼ hardening). heart failure a failure of the heart to pump sufficient blood
from the chambers into the aorta, inadequate supply of blood
reaches organs and tissues. hypertrophy increase in thickness of muscle. myocardial infarction death of an area of heart muscle due to
blockage of a coronary artery by blood clot and atheroma;
medical term for a heart attack or coronary thrombosis. renoprotection protection of the nephrons of the kidney from
damage, destruction, and amelioration of albuminuria. generally very few symptoms associated with high blood pressure. Dizziness and headaches may occur in some patients but generally health complaints may not surface for 5–20 years, thus the term ‘‘the silent killer.’’
- I. MEASUREMENT OF BLOOD PRESSURE
The instrument used to measure blood pressure is called a sphygmomanometer. It measures the air pressure needed to raise a column of mercury (Hg). The instrument consists of an inflatable cuff connected to a small bulb pump and a pressure gauge. By means of the inflatable cuff, which encircles the limb (usually the upper arm), air pressure within the cuff is balanced against the pressure in the artery (usually the brachial artery at the elbow). The pressure is estimated by means of a mercury or aneroid manometer. The mercury manometer is the most accurate pressure gauge. The aneroid gauge is frequently used instead of the mercury manometer because it is more compact and is convenient as a portable instrument. Some electronic instruments may give falsely high diastolic readings, but manufacturers will improve these to meet market demands. - II. HOW HIGH IS HIGH?
The World Health Organization (WHO) and many experts agree that in individuals under age 65, a systolic blood pressure equal to or greater than 140 mmHg and a diastolic blood pressure of 90 mmHg or above is ab¬normal. Optimal systolic blood pressure is less than 120 mmHg and optimal diastolic blood pressures are less than 80 mmHg. In patients age 65–80 a systolic pressure greater than 165 on three or more readings weeks or months apart is considered hypertension. The Framingham Study and other studies indicate a significant increase in car¬diovascular risk in individuals with a blood pressure in the borderline range. An individual is considered to have high blood pressure if several readings exceed 140/90, especially if three consecutive readings are elevated. The risk at any level of hypertension, including borderline hypertension, is greatly increased by smoking or a high blood cholesterol. Mild hypertension is extremely common, and over a 10- to 15-year period increases the risk of stroke, heart attack, and heart failure. Clinical studies have documented that blacks develop organ damage (stroke, heart failure, and damage to the kidneys) much quicker than whites at the same level of hypertension. - III. CAUSES OF HYPERTENSION A. Primary (Essential) Hypertension
In the majority of cases of hypertension, no detectable underlying disease is present. There are several theories as to why the blood pressure may be increased. This type - IV. PATHOGENESIS OF PRIMARY ESSENTIAL HYPERTENSION
A. Salt Hypothesis - V. COMPLICATIONS
A. Effects on Arteries and Heart - VI. SYMPTOMS
There is little doubt that hypertension either leads to early death or inflicts serious physical handicaps to millions. Blood pressure may be mildly or moderately elevated for several years without symptoms until the occurrence of stroke, heart attack, or heart failure. - VII. INVESTIGATIONS
Blood, urine, and other tests are performed to determine if hypertension is primary, that is, without a cause, or secondary to diseases of organs, especially the kidney. These tests will also serve as a baseline for future com¬parison and as a means for detecting side effects of some antihypertensive drugs. The tests and the reasons for their use are listed below. - VIII. NONDRUG TREATMENT
The majority of patients with mild primary hypertension are advised to persist with a one-year trial of nondrug treatment. It is important to understand the essential requirements of the program. The hypertensive must be aware of the dangers of the so-called silent killer to become sufficiently motivated to comply with self-imposed treatment. Individuals who persist with nondrug treatment - IX. DRUG TREATMENT
A. Number of Drugs Available - BIBLIOGRAPHY
ALLHAT: Officers and Coordinators for the ALLHAT Collabo¬rative Research Group. JAMA, 288:2981–2997, 2002. ALLHAT: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial. Major cardiovascular events in hypertensive patients randomized to doxazosin vs. chlorthalidone. The ALLHAT