High Blood Pressure or Hypertension Causes.

April 23, 2010 110 comments

High Blood Pressure Causes or Risk Factors.

Read “What is Blood pressure” so as to get an idea of the basic knowledge of this subject, wherein the normal levels of the blood pressures are explained. However, blood pressure levels are tabulated below and this will give you an idea of where you stand. High Blood Pressure or Hypertension as it called, is some thing you do not want to have, because its effects can be very dangerous. Knowing each cause of high blood pressure therefore becomes important so that you can avoid these high blood pressure causes or Hypertension Risk factors and thereby avoid having high blood pressure. These Reasons for High Blood Pressure are explained below.

What is High Blood Pressure or Hypertension.

High Blood pressure is diagnosed when the blood pressure is above the normal. The chart below is self explanatory.

High Blood Pressure Chart.

showing High Blood Pressure readings.

————————————-Systolic——————– Diastolic

(mm of hg) ( mm of hg)

Normal 100 to 120 60 to 80

Pre hypertensive 120 to 140 80 to 90

Hypertensive (stage 1) 140 to 160 90 to 100

Hypertensive (stage 2) > 160 > 100

Classification of hypertension (High Blood Pressure).

There are two types of hypertension:

1) Essential hypertension : Found in more than 95% of the cases and wherein the cause is unknown .

2) Secondary hypertension : Found in 5% of cases and which is caused by a kidney pathology or a tumour of the adrenal glands. The adrenal glands are situated on top of the kidneys.

There are cases where blood pressure may rise to above 200 mm hg during exercise only. This is called exercise hypertension and such cases are potential candidates for secondary hypertension.

What Causes High Blood Pressure|High Blood Pressure Risk Factors.

1) Essential hypertension causes are not known, but there is found to be an association of certain predisposing factors.

a) Age and High Blood Pressure. At an advanced age, you become more prone.
b) Salt intake and High Blood pressure. A normal salt intake of 3.8 gms daily is recommended for individuals of age between 20 to 50 yrs. Some of the cases of essential hypertension have been found to take a higher salt intake of more than 5gms daily.
c) Hereditary predisposition to High Blood Pressure is an important factor and is seen in about 30 % of the cases. An individual with either one or both parents of hyper tension carries twice the risk of getting hypertension.
d) Loss of elasticity of the peripheral or distal arterioles (small arteries) is another factor as this condition causes resistance to the blood flow and thus increases the pressure of the blood inside the arterioles .
e) Smoking causes High Blood Pressure.
f) High alcohol intake causes High Blood Pressure.
g) Long standing diabetes is associated with High Blood Pressure.
h) Certain medicines like steroids cause High Blood Pressure.

2) Secondary hypertension is due to some pathology and is found in 5% of the hypertensive cases.

a) Renal artery stenosis causes High Blood Pressure.

Renal artery narrowing may be caused by thickening of the arterial wall due to a condition called fibromyalgia or it may result from increased deposit of cholesterol plaques inside its walls due to increased level of cholesterol in the blood. Narrowing of the renal artery causes restricted blood flow to the kidney. This stimulates the kidney to secrete two hormones called rennin and angiotensin. These along with aldosterone from the adrenal gland cause the peripheral arterioles in the body to become stiff thus increasing the resistance to the blood flow and rise in blood pressure.

Diagram of Renal artery stenosis

b) Adrenal gland tumors cause High Blood Pressure.

Adrenal gland tumors cause stimulation of the adrenal glands to secrete excessive aldosterone which causes blood pressure rise. One of these tumors causes excessive loss of potassium in urine and thus can be diagnosed by decreased levels of potassium in the blood in a hypertensive patient.

Pheochromocytoma is another tumour of the adrenal gland which causes hypertension by increasing secretion of catecholamines. This tumor causes recurrent bouts of hypertension along with flushing of the skin, palpitations and excessive sweating.

These tumours can be diagnosed by blood and urine tests and imaging in cases suspected due to their symptoms as described above.

These tumours are to be removed surgically and most of the time the hypertension corrects itself after the surgery.

c) Coarctation of the aorta causes High Blood Pressure.

This is a constriction of the aorta occurring usually just above the renal arteries. The aorta is the main blood vessel into which the heart pumps the blood . This constriction causes reduced blood supply to the kidneys and rise in blood pressure as explained above in (a). Treatment is surgical and occasionally balloon angioplasty may also help.

Diagram of coarctation of aorta

d) Obesity is a major cause of High Blood Pressure.

Hypertension due to obesity is many a time associated with diabetes and increased cholesterol levels.

Action Step: If you identify any of these causes of essential hypertension in your case, you would do well to improve your life style habits and keep periodically checking your blood pressure. Try and rule out the High Blood Pressure Cause if you are associated with one.