When hypertension occurs as a result of another condition, it’s known as secondary hypertension. Chronic kidney disease is a common cause. Treatment involves treating the underlying cause.

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Hypertension, or high blood pressure, occurs when the pressure inside blood vessels is too high. High blood pressure can lead to a number of complications if not treated. These include stroke, heart disease, and kidney damage.

Hypertension can be categorized as either primary or secondary hypertension. Primary hypertension, also known as essential hypertension, can be the result of factors like diet, genetics, and stress.

Secondary hypertension is caused by an underlying issue. One common cause of secondary hypertension is damage to kidney tissue. If kidneys are damaged, they may not be able to process fluids well enough to maintain healthy blood pressure.

This type of hypertension may be treated, even cured, if the underlying cause is identified and treated. But if it isn’t, it can lead to complications, including aneurysm and organ damage.

Here, learn more about secondary hypertension, what causes it, and how it’s treated. Plus, find out what symptoms may indicate you have this condition.

Primary hypertension and secondary hypertension both cause high blood pressure. They can both have serious complications, including stroke and aneurysm. But they’re caused by different things, and treatments vary. Here’s a closer look.

Primary hypertension

Primary hypertension does not have a clear cause, but some risk factors increase a person’s chance of developing it. These include:

  • having excess weight
  • eating a diet high in salt
  • a family history of the condition
  • older age
  • drinking too much alcohol

Secondary hypertension

Secondary hypertension has an underlying cause. It’s responsible for the high blood pressure. However, it’s not always identified, which means it’s not always treated properly.

Secondary hypertension is less common than primary hypertension, but certain groups of people are more frequently impacted than others. This includes younger patients under 18. In fact, 70–85% of hypertension cases in children under 12 years old are the result of secondary hypertension.

It’s also responsible for about 17% of hypertension diagnoses in adults over 65. Primary hypertension is more common in this age group.

The most common cause of secondary hypertension is renal parenchymal disease which is scarring or damage to kidney tissue. Several types of disorders are grouped in this category, including diabetic nephropathy and polycystic kidney disease.

More than half of people with renal parenchymal disease will have hypertension, and more than two thirds of people with advanced chronic kidney disease have hypertension as well. Hypertension becomes more common as the condition worsens.

It can be a bit of a double-edged sword: High blood pressure accelerates the deterioration of kidney function.

Other possible causes of secondary hypertension include:

  • Hormone disorders: The endocrine system regulates the hormones in the body. Issues within this system may cause higher-than-average blood pressure. These disorders include primary aldosteronism and Cushing syndrome.
  • Physical changes to the kidneys: The blood vessels that carry blood between the heart and kidneys can become narrowed by plaque, tumors, or other conditions. This reduces blood flow and increases blood pressure. The heart has to work hard to properly supply the body with blood.
  • Blood vessel abnormalities: In some cases, the narrowed artery is present at birth, but it may not be found until high blood pressure is diagnosed. This is a leading cause of secondary hypertension in young people and children.
  • Tumors: Tumors on the adrenal glands, which are located on top of the kidney, can cause hypertension. These tumors impact the way the endocrine system works. They may also restrict blood flow.
  • Other possible causes of secondary hypertension: Several other conditions are linked to this issue. These include obstructive sleep apnea, preeclampsia (high blood pressure while you’re pregnant), and the use of some medications, drugs, and alcohol.

Like primary hypertension, secondary hypertension does not cause any specific symptoms. You may not know you have this condition until you have a blood pressure exam.

There are signs or symptoms that could indicate to your doctor that the hypertension is the result of another condition, however. These include:

  • hypertension that’s resistant to medication
  • hypertension that no longer responds to medication, even if it previously worked
  • hypertension in a non-Black patient younger than 30 years old without any other risk factors (such as family history or obesity)
  • hypertension in a person before puberty
  • the presence of high blood pressure complications, such as acute kidney damage, headache, or nausea

Secondary hypertension may not respond to medication alone. If the underlying cause is not identified, your blood pressure may remain high. In that case, it can still cause complications.

If the cause is identified, treatment is usually successful. The specific treatment for secondary hypertension will depend on what the cause is. Some of these possible treatments include:

  • Medications: Several types of medication may be helpful in treating high blood pressure. Diuretics, for example, help the kidneys eliminate water and sodium. This reduces the amount of fluid cycling through blood vessels. That can lower blood pressure.
  • Surgery: If a tumor is found, surgery may be needed to remove it.
  • Lifestyle changes: Certain changes to behavior and choices may help reduce high blood pressure. These changes are usually done along with other treatments. These include eating less salt, exercising regularly, drinking only in moderation, and maintaining a healthy weight.

Secondary hypertension is high blood pressure that’s caused by an underlying health issue. Common causes include kidney disease, tumors, and hormone disorders.

Finding the underlying cause of secondary hypertension can help determine a possible treatment. It can also reduce the risk of complications.

Secondary hypertension may be resistant to standard treatments, such as medication. If the underlying issue is found and addressed, the treatments are usually very successful.

Early detection of high blood pressure is important for many reasons. Adding this routine test to regular exams is a good way to find this issue and begin treatment.