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Definition of high blood pressure
What to do in case of hypertension?
For a better understanding of blood pressure The follow-up of a high blood pressure
High blood pressure damage High blood pressure and special cases
Why does high blood pressure exist? The self-measurement of blood pressure
How to measure high blood pressure? About Us
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IV - Why does high blood pressure exist?

4.1 - Most of the time, there is no explanation for this high blood pressure
But sometimes a disease is responsible for hypertension:
the secondary arterial hypertensions

4.2 - The medical procedure
4.3 - Causes
        4.3.1 - Drugs
        4.3.2 - An hormonal disorder

        4.3.3 - High blood pressure induced by the kidney
        4.3.4 - A rare cause: presence of an obstacle in the aorta


4.3.3 - High blood pressure induced by the kidney

Two kinds of kidney diseases can be the cause of high blood pressure: renal artery disease, which supplies blood to the kidney, and the disease of the kidney itself.

1 - Disease of the renal artery which supplies the blood to the kidney


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Sometimes, the artery supplying the blood to the kidney is blocked and causes a stenosis, often due to an arteriosclerosis. As the kidney is less supplied in blood, it synthesizes substances supporting the supply of blood in the kidney. These substances are called renin, angiotensin, and aldosterone, and involve a rise in the blood pressure.

In this case, physicians speak of a secondary hyperaldosteronism, i.e. that the aldosterone is not secreted directly by the suprarenal gland but indirectly by a cascade of chemical reactions due to the obstruction of the renal artery.

The causes of this renal artery obstruction is often a thickening of the renal artery in women, in particular young women; and in men, arteriosclerosis is more likely to be responsible for the occlusion of the renal artery, especially if the man is a smoker, older, or presenting other factors of cardiovascular risk (too much cholesterol, diabetes mellitus).

What is the physician doing?

He first confirms the diagnosis of stenosis of the renal arteries which supply blood to the kidney. A renal echography with doppler of the renal arteries is then practiced and a renal arteriography is done afterwards if necessary.

With the results of these investigations, the doctor either chooses to treat his patient by anti-hypertensive drugs alone if the renal artery stenosis is not very significant, or he may decide to open this artery.

For that, he has the possibility of dilating the artery by using a small balloon directly placed in contact with the stenosis and then inflated. Sometimes a small spiral spring is introduced to maintain the renal artery in an open position.

Treatment is rarely surgical using the use of a bridging i.e. a surgical by-pass of an artery taken in another part of the body and installed after the renal artery stenosis.

The long-term complications of a renal artery obstruction are primarily the destruction of the kidney, which will secrete many toxic substances responsible for high blood pressure. At this stage, the treatment consists in surgically extracting the kidney which is not effective anymore.


2 - Kidney disease

All the serious and chronic diseases of the kidney can induce a high blood pressure. The mechanisms for a high blood pressure are mixed: on the one hand the kidney filters less water and thus increases the pressure in the arteries, and on the other hand, the kidney secretes substances which induce a contraction of the arteries responsible for an increase in the blood pressure.

What is the physician doing?

He detects the kidney disease using biological tests in blood and in the urine, and adapts his treatment to suit. Very often the treatment of the cause is not so effective and the doctor has to use antihypertensive drugs in tablet form.

At a very advanced stage, the treatment of a renal insufficiency by dialysis is necessary, which reduces the high blood pressure.

File last reviewed on : 18 dec 2011
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