Renal hypertension

Alternative names

Renovascular hypertension; Hypertension - renovascular

Definition

Renovascular hypertension (high blood pressure) is caused by narrowing of the arteries that carry blood to the kidneys.

Causes, incidence, and risk factors

Blood pressure is determined by the amount of blood pumped by the heart and the size and condition of the arteries. Many other factors can affect blood pressure, including the volume of water in the body; salt content of the body; condition of the kidneys; nervous system, or blood vessels; and levels of various hormones in the body.

Renovascular hypertension is a form of secondary hypertension (hypertension caused by another condition in the body). It occurs in less than 5% of all people with hypertension. Symptoms usually begin before age 30 or after age 50, depending on the cause of the damage to the kidney blood vessels.

Narrowing of the renal artery reduces blood flow to the kidney. Stenosis is often related to atherosclerosis but may be caused by injury to the artery that causes scarring. Reduced blood flow to the kidney leads to an excessive release of the hormone renin, a potent hormone that increases blood pressure.

Symptoms

headache is an occasional symptom. If your hypertension is severe, symptoms may include:

• tiredness
  
• confusion
  
• vision changes
  
• nausea and vomiting
  
• angina-like chest pain (crushing chest pain)
  
• congestive heart failure
  

Note: Usually, no symptoms are present.

Signs and tests

Elevated blood pressure measurements , repeated over time, confirm hypertension. Renovascular hypertension is often severely high and difficult to treat. Diastolic blood pressure (the "bottom" number, a reflection of the pressure in blood vessels when the heart is at rest) is often higher than 104 (normal is less than 80 to 90).

Renovascular hypertension is suspected when:

• The onset of hypertension occurs at an advanced age
  
• Stable, controlled hypertension suddenly becomes more difficult to treat
  
• Hypertension requires multiple medications for its satisfactory control
  

There may be signs of complications. Bruits ("whooshing" noises over an artery) may be heard with a stethoscope over the abdomen or flank areas.