In this article we will discuss about the Hypertension:- 1. Meaning of Hypertension 2. Classification of Blood Pressure 3. Treatment 4. Prevention.
Meaning of Hypertension:
Hypertension is an important cause of several major disease and it is amenable to treatment. Hence, measurement of blood pressure is a part of all routine clinical examinations of adults. Hypertension is a major risk factor for the development of cardiovascular disease.
It is defined as systolic blood pressure of 140 mm of Hg or greater and/or diastolic blood pressure of 90 mm of Hg or greater or any level of blood pressure in patients taking antihypertensive medications.
The pathological changes accompanied by hypertension are a thickening of the arterioles with hyaline material and, later, hypertrophy of the myocardium of the left ventricle. If untreated, moderate hypertension eventually leads to cardiac failure, with dilatation of the left ventricle and congestion of the pulmonary or systemic veins. It also causes ischaemic changes in the kidney, nephrosclerosis.
The blood pressure if very high is said to be malignant hypertension. The heart, kidneys, retinal and other arteries are quickly affected and it shows immediate risk of a dangerous vascular accident. Therefore, vigorous treatment is most essential.
80 per cent of cases suffer from essential hypertension. Treatment has to be symptomatic. In the remaining cases the hypertension is usually secondary to renal disease, e.g., glomerulonephritis or pyelonephritis, and less commonly, to an endocrine disorder, e.g., Cushing’s syndrome, acromegaly, pregnancy also show hypertension.
Classification of Blood Pressure:
a. Hypertension frequently affects several members of a family and there is a high correlation between the blood pressures of identical twins.
b. Individual susceptible to hypertension is related to decreased activity of (Na+, K+) ATPase, the enzyme that through the sodium pump maintains intracellular concentrations of Na+ and K+. The activity of the enzyme is genetically determined.
a. Hypertension commonly accompanies obesity though it may occur in thin people.
b. Obese patients with hypertension, if reduce their weight to normal value, their blood pressure frequently returns to normal without any other treatment. This indicates that in susceptible individuals obesity is a direct cause of hypertension.
High salt intake in some countries causes hypertension; but in some other countries high salt intake shows no effect. It is, therefore, assumed that there is a threshold for salt intake, as yet undefined, above which hypertension commonly arises in susceptible individuals and that susceptibility is genetically determined.
D. Other Possible Risk Factors:
a. Stress, either mental or physical, raises the blood pressure immediately but this is only temporarily.
b. Environmental stresses may contribute to hypertension and of the theory that individuals with a poor capacity for relaxation are more prone to hypertension indicate that stress is not a major risk factor.
c. Inactivity may be a risk factor but is only a minor one.
d. Alcohol intake (> 3 units/day for men; > 2 units/day for women).
e. Physical activity.
g. Drags (e.g., NSAID, Oral contraceptives).
h. Renal diseases.
j. Conn’s syndrome (tetany, muscle weakness, polyuria, hypokalemia).
Factors involved in pathogenesis of hypertension:
i. Laboratory Investigations:
Urine for protein, glucose and microscopic (RBCs/other segments) haemoglobin, fasting blood glucose, serum creatinine, potassium and total cholesterol.
ii. Additional Investigations:
Lipid profile, Uric acid
Treatment of Hypertension:
Life style measures:
a. Maintain normal weight for adults (body mass index 20-25 kg/m2).
b. Reduce salt intake to < 100 mmol/day (< 6 gm. NaCl or < 2.4 gm. Na+/d).
c. Limit alcohol consumption to < 3 units for men and < 2 units/day for women.
d. Aerobic exercise (e.g., walking, cycling, swimming) > 3 min/day (at least three days of the week).
e. Consume at least five portions/day of fresh fruits and vegetables. Fish consumption rather than meat should be recommended. High intake of fibres, grains, vegetables and fruits improve BP control.
f. Reduce the intake of total and saturated fat.
a. Achieve gradual reduction of blood pressure.
b. Use low doses of antihypertensive drugs to initial therapy.
c. Choice of an antihypertensive agent is influenced by age, concomitant risk factors, pressure of target organ damage, other coexistence diseases and socio-economic condition.
d. Use of long acting drugs providing 24 hr efficacy ensures smooth and sustained control of blood pressure. Once daily application also improves patient compliance.
Prevention of Hypertension:
a. The dietary restriction is the reduced intake of salt.
b. It is advised widely not to use table salt and to use a minimum salt in home cooking. It is more important for the public to know that prepared meats contain about 20 times as much salt as is present in the original fresh meat.
Chips and crisp potatoes are very rich sources of salts. Salted and canned fish are fine for an occasion but if eaten frequently may increase salt intake greatly. Many snack foods are rich in salt.
c. As a preservative, salt is added to manufactured foods. But it should be such as to be ineffective. Manufacturers are not unresponsive to medical opinion and have greatly reduced the previously high salt content of infant foods when it was shown that this was a cause of hyperosmolar dehydration, a serious disorder in infants.
A significant amount of salt is added to bread, butter and cheese. It is to be looked upon as medicinal products that low salt bread, butter and cheese are obtained easily. If there is a popular demand for low salt foods of all sorts, manufacturers will produce and advertise them.
d. Legislation to restrict the addition of salt to foods will be difficult to enforce. A more practical approach will be to provide more money and support for appropriate health education.