Primary Aldosteronism (Conn's Syndrome)
What is Primary Aldosteronism (Conn's Syndrome)?
Primary aldosteronism is a condition where your adrenal glands make too much aldosterone. This hormone normally helps control blood pressure by managing sodium and potassium levels. When your body produces too much, sodium builds up and potassium drops.
This hormone imbalance leads to high blood pressure that does not respond well to standard medications. About 5 to 10 percent of people with high blood pressure have primary aldosteronism. Many cases go undiagnosed because the symptoms can be subtle or mistaken for regular high blood pressure.
The condition is sometimes called Conn's syndrome, named after the doctor who first described it in 1955. It typically results from a benign tumor on one adrenal gland or from overactive tissue in both glands. Early detection matters because this form of high blood pressure can be treated more effectively when the root cause is identified.
Symptoms
Common symptoms of primary aldosteronism include:
- High blood pressure that is difficult to control with medication
- Muscle weakness or cramping
- Frequent urination, especially at night
- Excessive thirst
- Fatigue or feeling tired without clear reason
- Headaches
- Numbness or tingling sensations
- Temporary paralysis in severe cases
Many people with primary aldosteronism have no obvious symptoms beyond high blood pressure. Low potassium levels cause most of the noticeable symptoms, but about 40 percent of patients maintain normal potassium levels. This makes the condition harder to spot without specific testing.
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Causes and risk factors
Primary aldosteronism happens when one or both adrenal glands produce excess aldosterone. The most common cause is a benign tumor called an aldosterone-producing adenoma, which affects one gland. The second common cause is bilateral adrenal hyperplasia, where both glands become overactive. Rare causes include adrenal cancer or inherited genetic conditions that run in families.
Risk factors include having high blood pressure before age 40, resistant high blood pressure that requires three or more medications, or low potassium levels without clear explanation. A family history of early-onset high blood pressure or stroke before age 40 also increases risk. Sleep apnea appears more common in people with primary aldosteronism, though the connection is not fully understood.
How it's diagnosed
Diagnosis begins with blood tests that measure aldosterone and renin levels. Doctors look for an elevated ratio between these two hormones. High aldosterone with low renin strongly suggests primary aldosteronism. Potassium levels are also checked, though normal levels do not rule out the condition. Your doctor may ask you to stop certain blood pressure medications before testing since they can affect results.
Specialized confirmatory testing is typically needed beyond standard blood panels. These tests help distinguish primary aldosteronism from other causes of high blood pressure. If blood tests suggest the condition, imaging studies like CT scans help identify tumors or gland enlargement. Talk to your doctor about whether specialized aldosterone testing is appropriate for your situation.
Treatment options
Treatment approaches for primary aldosteronism include:
- Medications called mineralocorticoid receptor antagonists that block aldosterone effects
- Surgical removal of the affected adrenal gland when a single adenoma is identified
- Potassium supplements to restore normal levels
- Sodium restriction to help control blood pressure
- Regular monitoring of blood pressure, potassium, and kidney function
- Medications to manage blood pressure if surgery is not an option
Surgery can cure primary aldosteronism when a single tumor is the cause. About 30 to 60 percent of patients no longer need blood pressure medication after surgery. When both glands are affected or surgery is not suitable, medication management works well for most people. Lifestyle changes like reducing sodium intake, maintaining a healthy weight, and regular exercise support treatment effectiveness.
Frequently asked questions
Primary aldosteronism is a specific cause of high blood pressure due to excess aldosterone hormone from the adrenal glands. Regular high blood pressure has no single identifiable cause. Primary aldosteronism often resists standard blood pressure medications and may cause low potassium levels. Identifying this condition matters because treatment targets the root cause rather than just managing symptoms.
Primary aldosteronism affects about 5 to 10 percent of people with high blood pressure. This makes it one of the most common causes of secondary high blood pressure. The condition is more prevalent than previously thought because many cases go undiagnosed. It appears more frequently in people with resistant high blood pressure, affecting up to 20 percent of that group.
Primary aldosteronism can be cured with surgery when a single adrenal tumor is the cause. About 30 to 60 percent of surgical patients no longer need blood pressure medication afterward. When both glands are involved or surgery is not possible, medication can effectively control the condition. Early diagnosis improves treatment outcomes and reduces long-term complications.
Untreated primary aldosteronism increases risk for heart disease, stroke, kidney damage, and irregular heart rhythms. The excess aldosterone causes more cardiovascular damage than regular high blood pressure at the same severity level. People with untreated primary aldosteronism have higher rates of heart attack and atrial fibrillation. Early treatment reduces these risks significantly.
Excess aldosterone tells the kidneys to hold onto sodium and release potassium into urine. This causes potassium levels in blood to drop over time. Low potassium leads to muscle weakness, fatigue, and cramping. Not everyone with primary aldosteronism develops low potassium, which can make diagnosis more challenging.
Diagnosis requires specialized blood tests measuring aldosterone and renin levels, typically calculated as a ratio. An elevated aldosterone-to-renin ratio suggests the condition. Confirmatory tests help verify the diagnosis since initial screening can show false positives. Imaging studies like CT scans identify tumors or gland abnormalities once blood tests indicate primary aldosteronism.
Some blood pressure medications interfere with aldosterone and renin testing. Your doctor may ask you to switch medications or stop certain ones for two to four weeks before testing. Never stop medications without medical guidance, as uncontrolled blood pressure poses immediate risks. Your healthcare provider will create a safe testing plan based on your specific situation.
Mineralocorticoid receptor antagonists like spironolactone and eplerenone are first-line medications. These drugs block aldosterone effects and help control blood pressure and potassium levels. Additional blood pressure medications may be needed for full control. Potassium supplements help restore levels in people with deficiency.
Lifestyle changes support medical treatment but cannot cure primary aldosteronism. Reducing sodium intake helps control blood pressure and reduces aldosterone effects. Regular exercise, maintaining a healthy weight, and limiting alcohol support cardiovascular health. These changes work best alongside medication or surgery rather than as standalone treatment.
Most cases of primary aldosteronism are not inherited and occur randomly. Rare familial forms exist where genetic mutations cause early-onset disease that runs in families. These inherited types account for less than 5 percent of cases. If you have primary aldosteronism and a family history of early high blood pressure, genetic testing may be recommended.