Condition Basics
What is secondary high blood pressure?
Secondary high blood pressure (secondary hypertension) is high blood pressure that's caused by another disease or condition. It can also be caused by certain medicines. If your doctor can treat what's causing the high blood pressure, it might lower your blood pressure.
What causes it?
Causes of secondary high blood pressure may include:
- Kidney disease, such as narrowing of the kidney arteries.
- Certain medicines, such as birth control pills, amphetamines, some antidepressants, steroids, and some nonsteroidal anti-inflammatory drugs (NSAIDs).
- Hormone related diseases, such as thyroid problems or a condition in which the adrenal glands make too much of the hormone aldosterone (hyperaldosteronism).
- Sleep apnea.
- Narrowing of the aorta (coarctation).
- Drinking a lot of alcohol.
- Drugs, such as cocaine or methamphetamine.
How hormones affect blood pressure
Hormones play a big role in controlling your blood pressure. They help control the amount of blood flow through your heart and arteries. For example, your body releases certain hormones (such as adrenaline) when it is under stress and needs more blood and oxygen.
How kidneys affect blood pressure
Your kidneys play a big role in controlling your blood pressure. As blood passes through your kidneys, they can adjust the amount of hormones produced. The hormones affect how much water and sodium move out of the body, which affects your blood pressure.
Your kidneys are essential for blood pressure control. As blood passes through your kidneys, special cells "measure" blood pressure in the blood vessels leading to your kidneys (renal arteries) and adjust the amount of the hormone renin that they secrete. Renin controls the production of two other hormones, angiotensin and aldosterone. And these hormones control the width of your arteries and how much water and salt is moved out of the body. Both of these affect blood pressure.
If your renal arteries become narrowed from a buildup of fat and calcium (called plaque), less blood flows to the kidneys, which causes blood pressure to rise.
How is it diagnosed?
If your doctor thinks that you may have secondary high blood pressure, you may need tests to diagnose other health problems. Your doctor will also check the medicines that you take, because some medicines can cause high blood pressure as a side effect.
Your doctor may think that you have secondary high blood pressure if:
- Your blood pressure has suddenly gone up since it was last checked.
- You are younger than 30 and have high blood pressure.
- You have tried different types of medicines and lifestyle changes such as healthy eating and being active, and you still have high blood pressure.
- You have symptoms of health problems that may raise your blood pressure.
- Your kidneys aren't working as well as they should.
How is secondary high blood pressure treated?
Secondary high blood pressure is typically treated by treating the cause of the high blood pressure. Your treatment depends on what is causing your high blood pressure and whether the high blood pressure should be lowered as soon as possible to prevent problems.
If a health problem is the cause, then high blood pressure may return to normal when the other health problem is treated. But treating the condition that has caused your secondary high blood pressure may not always lower blood pressure back to a normal level. In this case, you may need to treat the high blood pressure too.
If a medicine is the cause, then high blood pressure may return to normal if the medicine is stopped or the dose is adjusted.