Health Authority

Kidney disease can cause secondary hypertension. This type of secondary hypertension is called renal hypertension because it is caused by a problem in the kidneys. An important cause of renal hypertension is narrowing (stenosis) of the artery that feeds the kidneys (renal artery). Among young people, especially women, the narrowing caused by a thickening of the muscular wall of the arteries will kidneys (fibromuscular hyperplasia). In the elderly, generally narrowing due to heavy, fat-containing (atherosclerotic) plaques that block the renal artery.







How does the narrowing of the renal artery causes blood pressure? First, the reduced renal arteries reduce the blood flow and affects the kidneys. This lack of blood then stimulates the kidneys produce hormones, renin and angiotensin. These hormones and aldosterone by the adrenal gland, causes constriction and increased stiffness (resistance) of the peripheral arteries throughout the body, leading to high blood pressure.

Renal hypertension is usually first suspected when high blood pressure was a young or new onset of hypertension found in an older person. Screening for renal artery narrowing then may include renal isotope (radioactive) imaging, ultrasonographic (sound wave) imaging, or magnetic resonance imaging (MRI) and renal arteries. The purpose of these tests is to determine whether the restricted blood flow to the kidneys and whether angioplasty (the restriction of the renal arteries) is likely to benefit. However, if the ultrasound evaluation reveals a high resistive index within the kidney (high resistance to blood flow), angioplasty can improve blood pressure in hypertension due to chronic long-term damage is already there.

If any of these tests are suspicious or unusual medical renal artery stenosis is high enough, renal angiography (X-ray study, in which dye is injected into the renal artery) is performed. Angiography is the ultimate test to see really small renal artery.

A narrowing of the renal artery can be treated with balloon angioplasty. In this procedure, the doctor's son from a long narrow tube (catheter) into the renal artery. Once the catheter is there, the renal artery is expanded by inflating a balloon at the tip of the catheter and placing a permanent stent (a device that extends the narrowing) of the artery at the site of stenosis. This procedure usually results in improved blood flow to the kidneys and lower blood pressure. Moreover, the procedure also preserves kidney function that he was deprived of its normal blood supply. This is rarely needed today to open surgery for renal artery narrowing.

Any other chronic kidney disease, which reduces the kidney can also cause low blood pressure due to hormonal disorders and / or maintenance of salt.

It is important to remember that not only can cause high blood pressure, kidney disease, hypertension, but can also cause kidney disease. Therefore, all patients with hypertension should be evaluated for the presence of kidney disease so they can be properly treated.