Hypertension
2010-02-25

Hypertension, commonly called High Blood Pressure is difficult to define as there are variation in terms of Age, sex, race, ethnicity etc. However, Hypertension may be defined as a persistent rise in Blood pressure readings of at least three consecutive times for an individual who is previously normotensive.

Blood pressure is always the product of cardiac output and total peripheral resistance. There are various factors that affect or influence the Blood Pressure. Among these are the chemical changes in the blood and the volume changes. These changes affect the determinants of Blood Pressure, thus cardiac output and TPR. For instance a rise in blood volume may cause or increase renal perfusion and by a regulatory mechanism known as the Renin Angiotensin Aldosterone pathway the Blood pressure is restored.

All factors that cause hypertension in one way or the other affect the normal regulation of Blood pressure in the body.

Causes of Hypertension include

renal causes like renal failure, polycystic kidney disease, chronic renal infections such as pyelonephritis, glomerulonephritis etc, hydronephrosis, hypernephroma

endocrine causes like Diabetes Mellitus, Phaechromocytoma, Hyperthyroidism, Acromegaly, Hypercalcemia, Cushing syndrome etc

Drug abuse (steroidal or contraceptives)

Pregnancy thus toxemia in pregnancy

cardia causes like coarctation of the aorta

Symptoms of HPT

Most people with HPT do not show classical symptoms. Common symptoms like Headache, Palpitation, Chest pains, dizziness and tiredness. Other symptoms and signs may be due to underlying causes. For instance anuria, dysuria, hematuria may be present if HPT is due to renal causes. Blood sugar may be elevated if DM is present.

Risk factors of HPT include

Obesity

Family History

Atherosclerosis

Ethnicity

Lack of Exercise

Alcohol consumption

High salt diet

Management of Hypertension

a) Calcium Channel Blocker

These are agent that block the entry of calcium into the heart muscle. The heart muscle needs calcium to contract and therefore if calcium is blocked the muscle somehow relax. This effect reduces the rate at which the heart beat (HR) and so the BP goes down

b)Vasodilators

These are agents that cause the blood vessels to open up. When the vessels open, they offer poor resistance to the flow of blood. The reduction in resistance leads to lowered BP

c) ACE Inhibitors

These are agents that interferes with the Renin Angiotensin Pathway in the regulation of Blood pressure. The agents block the action of ACE, thus the angiotensin converting enzyme, thereby preventing sodium or salt retention. It promotes diuresis through the loss of Sodium and water.

d) Adrenergic antagonist

these agents block the synthesis or the release of adrenalin in the body. Adrenalin is known to increase heart rate as well as constrict blood vessels to increase the BP. with these agents the actions of adrenalin is inhibited.

Preventive Measure

Avoid High sodium diet , avoid smoking and alcoholism, reduce or avoid high cholesterol diets, Reduce weight, Exercise.