What Is Renal Hypertension?
Renal hypertension, also called renovascular hypertension, is elevated blood pressure caused by kidney disease. It can usually be controlled by blood pressure drugs. Some people with renal hypertension can be helped by angioplasty, stenting, or surgery on the blood vessels of the kidney.
Causes of Renal Hypertension
Renal hypertension is caused by a narrowing in the arteries that deliver blood to the kidney. One or both kidneys' arteries may be narrowed. This is a condition called renal artery stenosis.
When the kidneys receive low blood flow, they act as if the low flow is due to dehydration. So they respond by releasing hormones that stimulate the body to retain sodium and water. Blood vessels fill with additional fluid, and blood pressure goes up.
The narrowing in one or both renal arteries is most often caused by atherosclerosis, or hardening of the arteries. This is the same process that leads to many heart attacks and strokes. A less common cause of the narrowing is fibromuscular dysplasia. This is a condition in which the structure of the renal arteries develops abnormally for unclear reasons.
Symptoms of Renal Hypertension
Renal hypertension usually causes no symptoms. The narrowing in the arteries can't be felt. Unless it's dangerously high, high blood pressure causes no symptoms either. Symptoms of severely elevated blood pressure include:
- Blurry or double vision
- Bloody (pink-colored) urine
The vast majority of people with renal hypertension never experience these (or any) symptoms. High blood pressure is dangerous partly because there are no symptoms, so organ damage can occur slowly without being recognized.
Renal hypertension can cause chronic kidney disease. This is a slow decline in kidney function. Until the condition is well advanced, chronic kidney disease also causes no symptoms.
Because there are usually no symptoms, a doctor may suspect renal hypertension when someone has uncontrolled high blood pressure despite multiple medications or has unexplained chronic kidney disease.