Secondary hypertension (secondary high blood pressure) is high blood pressure that is a result of another medical condition. Essential hypertension, also known as primary hypertension, has no known cause and is thought to be linked to genetics, being physically inactive, being overweight and poor diet.
Secondary hypertension can be caused by conditions that affect the kidneys, arteries, heart or endocrine system. It can also occur during pregnancy.
Proper treatment of secondary hypertension typically involves controlling high blood pressure and the underlying condition that prompted it in order to reduce the risk of serious complications, including heart disease, kidney failure and stroke.
Secondary hypertension usually has no specific signs or symptoms, even if your blood pressure has reached extremely high levels. A few signs that can determine whether the condition is secondary hypertension include:
- Blood pressure that doesn’t respond to blood pressure medication
- Previous blood pressure medication that no longer works
- Extremely high blood pressure (160mmHg/100mmHg)
- Sudden high blood pressure levels before the age of 30 and after the age of 55
- No family history of high blood pressure
- Not being overweight
There are a number of conditions that can cause secondary hypertension. These include:
- The use of birth control pills
- The use of certain medications and supplements
- Being overweight
- Being pregnant
- Excessive alcohol consumption
- Diabetes complications
- Thyroid dysfunction
- Glomerular disease
- Renovascular hypertension
- Cushing syndrome
- Coarctation of the aorta
- Chronic kidney disease
- Sleep apnea
The greatest risk factor for having secondary hypertension is having a medical condition that can cause high blood pressure, in turn affecting the function of the kidneys, arteries, heart and endocrine system.
If left untreated, possible complications that can arise from secondary hypertension include:
- Metabolic syndrome: A cluster of disorders of the body’s metabolism that can increase the risk of developing diabetes, heart disease or stroke.
- Weakening and bulging of blood vessels
- Hardening and thickening of the arteries
- Weakened and narrowed blood vessels in the kidneys
- Thickened, narrowed or torn blood vessels in the eyes (can result in blindness)
- Memory troubles
- Poor concentration
- Heart failure
Secondary hypertension treatments often require taking blood pressure medications as well as making lifestyle changes to keep blood pressure levels low. These changes may include eating healthy foods, maintaining a healthy weight and exercising regularly.
Treating any underlying medication condition that affects high blood pressure levels is also important in order to stabilize blood pressure and reduce the risk of developing further complications.
Possible drug choices include:
- Thiazide diuretics: Diuretics (water pills) are medications that act on the kidneys to help rid the body of excess levels of sodium and water, in turn reducing blood volume. Possible side effects can include frequent urination and a higher risk of sexual dysfunction.
- Beta blockers: Beta blockers are medications that work to open blood vessels and reduce the workload on the heart. Possible side effects can include tiredness, a slowed heart rate, sleep disturbances and coldness on the hands and feet.
- Angiotensin-converting enzyme (ACE) inhibitors: Angiotensin-converting enzyme inhibitors are medications that help calm blood vessels by blocking the formation of a natural chemical that narrows blood vessels. Possible side effects may include dizziness and cough.
- Angiotensin II receptor blockers: Angiotensin II receptor blockers are medications that help calm blood vessels by blocking the action of a natural chemical that narrows blood vessels.
- Calcium channel blockers: Calcium channel blockers are medications used to help relax the muscles of the blood vessels and increase the supply of blood and oxygen to the heart while also reducing the heart’s workload. Possible side effects may include water retention, dizziness and constipation.
- Direct renin inhibitors: Direct renin inhibitors are a group of pharmaceutical drugs used to block the enzyme rennin from triggering the process that helps regulate blood pressure. Possible side effects include dizziness and diarrhea.