Primary aldosteronism is a condition which your body's adrenal glands produce too much of the hormone aldosterone, causing you to retain sodium and lose potassium.
Sodium and potassium normally work together to help maintain the right balance of fluids in your body, transmit nerve impulses, and contract and relax your muscles. But excess aldosterone causes sodium retention, which in turn retains excess water, increasing your blood volume and blood pressure.
Doctors once considered primary aldosteronism rare. However, as screening for primary aldosteronism becomes more common, evidence is emerging that it may be responsible for as many as one in eight cases of high blood pressure.
Primary aldosteronism is more common in people with severe, uncontrolled high blood pressure. Treatment for primary aldosteronism depends on the underlying cause. Treatment options include medications, lifestyle modifications and surgery.
Though 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 such hormone is aldosterone, which manages your body's balance of sodium and potassium. In primary
aldosteronism, your body produces too much of this hormone, causing you to retain sodium and lose potassium.
The most common known cause of primary aldosteronism is a benign growth (aldosteronoma) in an adrenal gland — a condition also known as Conn's syndrome.
Other causes include :
- Overactivity of both adrenal glands (bilateral adrenal hyperplasia)
- Rarely, cancerous (malignant) growths in the outer layer (cortex) of the adrenal gland
- Rarely, genetic mutations
A rare type of primary aldosteronism called glucocorticoid-remediable aldosteronism (GRA) runs in families. This condition may cause high blood pressure in children and young adults. Genetic testing can identify people at risk.
When to seek medical advice :
If you have any of the following signs or symptoms, see your doctor :
- Muscle cramps and weakness not explained by physical activity
- Temporary paralysis
- Unexplained, excessive thirst or urination
Have your blood pressure checked regularly in order to catch high blood pressure in its early stages, before serious damage occurs to your heart or kidneys. Have a screening at least every two years, depending on your current age and health, medical history and other risk factors for cardiovascular disease. Ask your doctor about the best interval for you.
High blood pressure that doesn't respond completely to medication is the most common sign of primary aldosteronism. Other common signs include low potassium levels (hypokalemia) and the presence of a noncancerous (benign) tumor on one or both of the adrenal glands.
Less common signs and symptoms of this condition may include :
- Muscle weakness and cramps
- Temporary paralysis
- Pricking, tingling sensation
- Excessive thirst
- Excessive urination
Your doctor may first suspect primary aldosteronism if you have high blood pressure and low blood potassium, but many people with this condition — especially those in the early stages of the disease — have normal potassium levels.
To diagnose primary aldosteronism, your doctor may measure the levels of aldosterone and renin in your blood. Renin is an enzyme released by your kidneys that helps regulate blood pressure. Many people with high blood pressure have low renin levels, but few also have the very high aldosterone levels that point to primary aldosteronism.
Dietary sodium, posture, blood potassium levels and certain medications can alter the results of this test. Your doctor will recommend a number of changes before the test to control these factors, including following a low-sodium diet, taking medications to control your potassium levels, and adjusting your current medications to eliminate those that can interfere with test results.
To confirm the diagnosis, your doctor also may attempt to suppress your aldosterone levels by artificially increasing your sodium levels. If you have primary aldosteronism, your aldosterone levels will remain high. Your doctor may use one of three tests :
- 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.
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.
Untreated high blood pressure may lead to heart attack; heart failure; another heart condition known as left ventricular hypertrophy; stroke; kidney disease or failure; and premature death.
Complications of low potassium levels include fatigue, muscle cramps, excess urination and cardiac arrhythmias.
Adrenal vein sampling increases your risk of a blood clot (thrombosis) developing at the site where blood is drawn.
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 may 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. Researchers are comparing the two drugs in clinical studies, but don't yet know whether eplerenone manages blood pressure and potassium levels as well as spironolactone does. Your doctor may recommend eplerenone if you experience serious side effects with spironolactone.
Lifestyle changes. All 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.
Primary aldosteronism caused by a benign tumor on your adrenal gland also can be effectively treated with mineralocorticoid receptor antagonists and lifestyle changes. However, high blood pressure and low potassium will return if you stop taking your medications.
Surgical removal of the adrenal gland containing the aldosteronoma (adrenalectomy) may permanently resolve both high blood pressure and potassium deficiency. Some people continue to have less severe high blood pressure after surgery, especially if they had chronic, uncontrolled high blood pressure before. Medications can help manage this condition.
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.