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Primary aldosteronism
By Mayo Clinic staffMayo Clinic Health Manager
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Definition
Your adrenal glands produce a number of essential hormones. One of these is aldosterone, which balances sodium and potassium in your blood. In primary aldosteronism, your adrenal glands produce too much aldosterone, causing you to lose potassium and retain sodium. The excess sodium in turn holds onto water, increasing your blood volume and blood pressure.
Doctors once considered primary aldosteronism rare. But as screening for primary aldosteronism becomes more common, it appears that the condition may be responsible for a number of cases of high blood pressure, especially those that are severe and hard to control.
Treatment for primary aldosteronism depends on the underlying cause. Options for people with primary aldosteronism include medications, lifestyle modifications and surgery.
Symptoms
The main signs of primary aldosteronism are:
- High blood pressure that takes several medications to control
- High blood pressure along with a low potassium level (hypokalemia)
When to see a doctor
Have your blood pressure checked regularly, especially if you have risk factors for hypertension, such as older age, diabetes, overweight, smoking or a family history of high blood pressure. Talk to your doctor about how often you should be screened.
Causes
Although your adrenal glands are each only about half the size of your thumb, these tiny titans dictate much of what happens in your body. Perched atop each of your kidneys, they produce hormones that help regulate your metabolism, immune system, blood pressure and other essential functions.
One of these hormones is aldosterone, which regulates the balance of sodium and potassium in your blood. In primary aldosteronism, your adrenal glands produce too much aldosterone, causing you to reabsorb sodium and excrete potassium.
Common conditions causing the overproduction of aldosterone include:
- A benign growth (aldosteronoma) in an adrenal gland — a condition also known as Conn's syndrome
- Overactivity of both adrenal glands (bilateral adrenal hyperplasia)
In rare cases, primary aldosteronism may be caused by:
- Cancerous (malignant) growths in the outer layer (cortex) of the adrenal gland
- Genetic mutations
- A rare type of primary aldosteronism called glucocorticoid-remediable aldosteronism (GRA) that runs in families and causes high blood pressure in children and young adults
Complications
The most serious complication of primary aldosteronism is high blood pressure. Untreated high blood pressure can lead to:
- Heart attack
- Heart failure
- Left ventricular hypertrophy — enlargement of the muscle that makes up the wall of the left ventricle, your heart's main pumping chamber
- Stroke
- Kidney disease or kidney failure
- Premature death
Some, but not all, people with primary aldosteronism have low potassium levels, which can cause fatigue, muscle cramps, excess urination and cardiac arrhythmias.
Preparing for your appointment
Your doctor may first suspect primary aldosteronism if you have high blood pressure and low blood potassium, although many people with this condition have normal potassium levels, especially in the early stages of the disease.
To diagnose primary aldosteronism, you'll need certain tests. Your doctor is likely to begin by measuring the levels of aldosterone and renin in your blood. Renin is an enzyme released by your kidneys that helps regulate blood pressure. The combination of a very low renin level with a high aldosterone level indicates that primary aldosteronism may be the cause of your high blood pressure.
This test can be performed while you're taking most blood pressure medications, but you'll need to discontinue taking drugs such as spironolactone and eplerenone six weeks before testing. Your doctor may also recommend avoiding other medications, including some over-the-counter pain relievers, and following a low-sodium diet before you take the test.
Tests and diagnosis
If the aldosterone-renin test suggests that you might have primary aldosteronism, you'll need another test to confirm the diagnosis, such as one of the following:
- Oral salt loading. You'll follow a high-sodium diet for three days before your doctor measures aldosterone and sodium levels in your urine.
- Saline loading. Your aldosterone levels are tested after sodium mixed with water (saline) is infused into your bloodstream for several hours.
- Fludrocortisone suppression test (FST). After you've followed a high-sodium diet and taken fludrocortisone — which mimics the action of aldosterone — for three days, aldosterone levels in your blood are measured.
Additional tests
If you receive a diagnosis of primary aldosteronism, your doctor will run additional tests to determine whether the underlying cause is an aldosteronoma or overactive adrenal glands. Tests may include:
- Abdominal computerized tomography (CT) scan. A CT scan can help identify a tumor on your adrenal gland or an enlargement that suggests overactivity. You may still need additional testing after a CT scan because this imaging test may miss small but important abnormalities or find tumors that don't produce aldosterone.
- Adrenal vein sampling. This is the most reliable test for determining the cause of primary aldosteronism. A radiologist draws blood from both your right and left adrenal veins and compares the two samples. Aldosterone levels that are significantly higher on one side indicate the presence of an aldosteronoma on that side. Aldosterone levels that are similar on both sides point to overactivity in both glands. Though essential for determining the appropriate treatment, this test increases your risk of a blood clot at the site where the blood is drawn.
Treatments and drugs
Treatment for primary aldosteronism depends on the underlying cause.
Bilateral adrenal hyperplasia
A combination of medications and lifestyle modifications can effectively treat primary aldosteronism caused by overactivity of both adrenal glands.
-
Medications. Mineralocorticoid receptor antagonists block the action of aldosterone in your body. Your doctor may first prescribe spironolactone (Aldactone). This medication helps correct high blood pressure and low potassium, but it may cause problems. In addition to blocking aldosterone receptors, spironolactone blocks androgen and progesterone receptors and may inhibit the action of these hormones. Side effects can include male breast enlargement (gynecomastia), decreased sexual desire (libido), impotence, menstrual irregularities and gastrointestinal distress.
A newer, more expensive mineralocorticoid receptor antagonist called eplerenone acts just on aldosterone receptors, eliminating the sex-hormone side effects associated with spironolactone. Your doctor may recommend eplerenone if you experience serious side effects with spironolactone. In addition to spironolactone or eplerenone, you may need further treatment for high blood pressure.
- Lifestyle changes. High blood pressure medications are more effective when combined with a healthy diet and lifestyle. Work with your doctor to create a plan to reduce the sodium in your diet and maintain a healthy body weight. Getting regular exercise, limiting your alcohol intake and stopping smoking also may improve your response to medications.
Aldosteronoma
Primary aldosteronism caused by a benign tumor on your adrenal gland also can be effectively treated with mineralocorticoid receptor antagonists and lifestyle changes, but high blood pressure and low potassium will return if you stop taking your medications.
Surgical removal of the adrenal gland containing the aldosteronoma (adrenalectomy) is usually recommended because it may permanently resolve both high blood pressure and potassium deficiency. Blood pressure usually drops gradually after a unilateral adrenalectomy. Your doctor will follow you closely after surgery and progressively adjust or eliminate your high blood pressure medications.
Lifestyle and home remedies
Effective treatments are available for primary aldosteronism, but don't count on these therapies keeping your blood pressure low on their own. A healthy lifestyle is essential for maintaining long-term heart health. Here are some healthy lifestyle suggestions:
- Follow a healthy diet. Limit the sodium in your diet by focusing on fresh foods and reduced-sodium products, avoiding condiments, and removing salt from recipes. Diets that also emphasize a healthy variety of foods — including grains, fruits, vegetables and low-fat dairy products — can promote weight loss and help to lower blood pressure. Try the Dietary Approaches to Stop Hypertension (DASH) diet — it has proven benefits for your heart.
- Achieve a healthy weight. If your body mass index (BMI) is 25 or more, losing as few as 10 pounds may reduce your blood pressure.
- Exercise. Regular aerobic exercise seems to lower blood pressure in some people, even without weight loss. You don't have to hit the gym — taking vigorous walks most days of the week can significantly improve your health. Try walking with a friend at lunch instead of dining out.
- Don't smoke. If you smoke, stop. Nicotine in tobacco makes your heart work harder by temporarily constricting your blood vessels and increasing your heart rate and blood pressure. Talk to your doctor about medications that can help you stop smoking.
- Limit alcohol and caffeine. Both substances can raise your blood pressure, and alcohol can interfere with the effectiveness of some blood pressure medications. Ask your doctor whether moderate alcohol consumption is safe for you.
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