High blood pressure is a type of low renin hypertension. It describes hypertension with low levels of an enzyme.

Renin works with other molecules in the body to keep your electrolytes balanced. If you have low renin levels, you may have too much salt in your body.

According to one 2018 study, LRH may affect up to 30 percent of people with hypertension.

It is important to determine the best course of treatment for high blood pressure. Your doctor will want to check for other factors.

Hypertension and the RAAS

To understand LRH, you first need to understand the renin-angiotensin-aldosterone system (RAAS).

  1. Renin is made in the kidneys. It starts the process.
  2. Angiotensinogen is a piece of the body that is broken down by renin.
  3. Another enzyme converts angiotensin I to angiotensin II, a protein hormone that can narrow your blood vessels to increase your blood pressure.
  4. Angiotensin II causes the adrenal glands above your kidneys to release aldosterone, another hormone. Aldosterone helps to manage the amount of salt in your blood.

The RAAS is responsible for controlling your blood volume and other vital factors.

When the RAAS works, high levels of renin increase your blood pressure. Even with low or typical renin levels, you experience high blood pressure with LRH. You may not have enough renin to help set off the processes that control your blood pressure.

Causes of LRH vary based on subtype. This 2018 study suggests it may be caused by:

  • There are genetic syndromes.
  • Genetic changes were acquired.
  • Environmental factors can affect the environment.

To determine the exact cause of your LRH, your doctor will consider your aldosterone level. The level of aldosterone in your blood can narrow down a search for the cause of your LRH.

High aldosterone levels

If your renin levels are low, but your aldosterone levels are high, you may have primary aldosteronism. It‘s also called hyperaldosteronism or Conn‘s syndrome.

Primary aldosteronism is the most common cause of LRH. A 2018 study indicates that it affects an estimated 6 percent of people with hypertension.

It can sometimes run in families according to the same study. A rare inherited gene abnormality can cause a condition called hyperaldosteronism.

Hyperaldosteronism can be caused by tumors on the adrenal glands.

Standard aldosterone levels

If your renin levels are low while your aldosterone levels are standard, the most likely cause is low renin essential hypertension (LREH). This is a form of primary or essential hypertension, meaning that no other health condition is responsible for your high blood pressure.

When other causes are ruled out, the case of low or high aldosterone may be diagnosed.

According to a 2012 study, low renin levels are seen more often in the Black community and in older adults.

Low aldosterone levels

If your renin and aldosterone levels are both low, research suggests there might be a number of acquired or genetic causes. Acquired causes include:

Genetic causes can be found.

  • Liddle syndrome. Liddle syndrome is a rare genetic disorder that causes high blood pressure due to atypical kidney function.
  • Mineralocorticoid receptor (MR) activating mutation. This is a genetic disorder that may interfere with your body‘s ability to regulate electrolytes. This leads to an inability to regulate your blood pressure.
  • Apparent mineralocorticoid excess (AME) syndrome. A 2018 study suggested that AME syndrome, which is a rare disease, is primarily linked to LRH in children.
  • Congenital adrenal hyperplasia (CAH). CAH is a rare inherited disorder that interferes with adrenal gland function.
  • Glucocorticoid resistance (Chrousos syndrome). Glucocorticoid resistance is a rare genetic condition that causes an insensitivity to glucocorticoids. This can lead to hypertension.
  • Gordon‘s syndrome. Gordon‘s syndrome is a rare genetic condition that may cause hypertension and high potassium levels.

Some of the genetic causes of LRH may not cause high blood pressure.

For example, CAH is a family of disorders with classical and nonclassical forms. According to the Children‘s Hospital of Philadelphia, its classical form usually presents with low blood pressure. Research from 2018 suggests that about two-thirds of people with CAH will have LRH with low aldosterone.

The underlying cause of the symptoms of LRH is unknown. You may not know you have it until your doctor orders a blood test.

The National Heart, Lung, and Blood Institute (NHLBI) notes hypertension itself also doesn’t cause symptoms until it causes serious complications, such as The heart disease is very serious..

Aside from high blood pressure, primary aldosteronism is usually associated with muscle weakness and low potassium levels in your blood (hypokalemia). This can cause increased thirst, cramps, and weakness.

People with LRH due to primary aldosteronism are also at higher risk of cardiovascular issues, according to a 2012 study. These can include:

Your doctor will ask you about your family history of hypertension and any symptoms you are experiencing before making a diagnosis. They may ask about any genetic disorders in your family.

Blood or urine testing is required to diagnose LRH. Your doctor will be looking at levels.

  • renin, with typical levels ranging from 1.9 to 3.7 nanograms per milliliter per hour (ng/ml/hour) according to the University of California, Los Angeles
  • To determine the type.
  • To check for hypokalemia.
  • cortisol, to check for steroid production by the adrenal glands

Your doctor may also perform a kidney function test.

“Doctors won’t know the cause of your LRH until they see how you respond to medication.”

Certain factors may affect your renin levels. Your doctor will consider these when evaluating your results. One 2018 study says these factors can include:

  • Taking certain drugs.
  • high salt intake
  • The first phase of the menstrual cycle is thefollicular.

If your doctor thinks that certain conditions in your family can be linked to hypertension, he might recommend genetic counseling.

You can treat your LRH with a combination of drugs and home management techniques. You may need surgery depending on the type. The goal of treatment is to improve the RAAS and lower your blood pressure.

Medications

Medication options for LRH depend on the subtype. According to the NHLBI, options may include the following:

Surgery

Doctors may recommend a surgery to treat tumors. The tumors on your adrenal glands are removed in this procedure.

Results may vary. However, the Society for Endocrinology estimates that surgery may help reduce blood pressure in over 70 percent of participants with primary hyperaldosteronism. Some people may also have a reduced need for their blood pressure medications.

Home management

Reducing your sodium intake could offset high blood sodium levels in LRH. It may also be helpful if you have salt-sensitive hypertension. To help you make dietary changes, your doctor may recommend the Dietary Approaches to Stop Hypertension (DASH) eating plan.

The NHLBI has funded studies that suggest the DASH diet reduces high blood pressure. Research from 2019 also indicates that this eating plan may have hypotensive effects on the RAAS.

Per the NHLBI, the DASH diet focuses on low sodium foods such as:

  • There are fruits.
  • vegetables
  • whole grains
  • There are nuts.
  • There are seeds.
  • The beans are legumes.

The DASH diet allows low fat poultry, fish, and dairy products. Your daily intake of salt should be between 1,500 and 2,300.

In addition to the DASH diet, your doctor may recommend other home care strategies to help control your blood pressure. The NHLBI lists lifestyle changes, including:

  • Managing stress.
  • quitting smoking
  • exercising.
  • Maintaining your ideal weight.
  • limiting the amount of alcohol consumed.
  • It takes 7 to 9 hours of sleep a night.

The RAAS is related to LRH. Most cases of low renin are acquired, with the risk increasing with age.

“You may not know you have LRH until your doctor gives you a blood test. LRH doesn’t usually cause any noticeable symptoms unless there are related problems.”

You can make changes to your diet and lifestyle to help manage LRH. Depending on the underlying cause, you may need certain medications. In rare cases, your doctor may suggest surgery.