Primary Hyperaldosteronism

Primary aldosteronism, Conn’s syndrome

Primary hyperaldosteronism is a condition where your adrenal glands produce too much of a hormone called aldosterone, leading to high blood pressure and potentially serious health problems. Once considered rare, it is now recognized as one of the most common causes of high blood pressure that doesn’t respond well to medication, affecting up to 10% of people with hypertension.

Table of contents

• What is primary hyperaldosteronism?
• Associated anatomy
• How common is the condition?
• Signs and symptoms
• Causes and types
• Who is at higher risk?
• Possible complications
• How is it diagnosed?
• Treatment options
• Outlook with treatment

What is primary hyperaldosteronism?

Primary hyperaldosteronism, also known as Conn’s syndrome, is a condition that occurs when your adrenal glands (small glands sitting on top of your kidneys) make too much aldosterone. Aldosterone is a steroid hormone that helps control the balance of salt and water in your body by regulating sodium and potassium levels in your blood.^[1]

When your body produces too much aldosterone, it causes your body to hold onto more sodium (salt) and lose potassium. This leads to increased blood pressure and can upset the balance of important minerals in your body called electrolytes.^[4] The condition is called “primary” because the problem starts in the adrenal glands themselves, not somewhere else in the body.^[3]

Associated anatomy

• Adrenal glands
• Kidneys

How common is the condition?

Primary hyperaldosteronism used to be considered a rare disorder, but today we know it affects many more people than previously thought. Studies suggest that 5% to 10% of all adults with high blood pressure have this condition.^[1] Among people with medication-resistant high blood pressure (blood pressure that doesn’t improve even with three or more medications), as many as 25% may have primary hyperaldosteronism.^[3]

The condition is more common in women than in men. Most people receive their diagnosis between the ages of 30 and 50, though it can occur at any age.^[1][4]

Signs and symptoms

Some people with mild cases of primary hyperaldosteronism have no noticeable symptoms. However, most people experience high blood pressure, which is often the main and sometimes only sign of the condition.^[3][4] The high blood pressure associated with primary hyperaldosteronism is usually hard to control and often requires four or more blood pressure medications.^[5]

While the classic description of primary hyperaldosteronism includes low potassium levels in the blood (called hypokalemia), this actually appears in only about a quarter of people with the condition.^[2][6] When low potassium does occur, it can cause its own set of problems.

Additional symptoms that may occur include:

• Fatigue or feeling extremely tired^[1]
• Headaches^[1][4]
• Muscle weakness and muscle cramps^[1][4]
• Excessive thirst^[1]
• Frequent urination (needing to pee more than usual)^[1]
• Blurred vision^[1]
• Dizziness^[3]
• Tingling and numbness^[3]
• Muscle spasms^[3]
• Temporary paralysis in severe cases^[3]

Causes and types

Primary hyperaldosteronism happens when something goes wrong within the adrenal glands themselves, causing them to produce too much aldosterone. The two main causes are aldosterone-producing adenomas (noncancerous tumors) and bilateral adrenal hyperplasia (enlargement of both adrenal glands).^[2]

About 35% of cases are caused by a single tumor in one adrenal gland that produces aldosterone. This specific situation is sometimes called Conn’s syndrome.^[6] About 66% of cases result from both adrenal glands being overactive.^[6]

Less common causes of primary hyperaldosteronism include:

• Enlargement of only one adrenal gland^[3]
• Cancerous tumors in the adrenal gland (very rare)^[1]
• Inherited disorders such as familial hyperaldosteronism types I, II, and III^[2][5]

It’s important to understand that primary hyperaldosteronism is different from secondary hyperaldosteronism. In secondary hyperaldosteronism, the adrenal glands produce too much aldosterone because of a problem somewhere else in the body, such as reduced blood flow to the kidneys, liver disease, heart failure, or pregnancy.^[1][3]

Who is at higher risk?

Anyone can develop primary hyperaldosteronism, but certain factors make it more likely. You may be at higher risk if you have:^[1]

• Low blood potassium levels
• High blood pressure that started before age 30
• High blood pressure requiring three or more medications to manage
• An adrenal tumor found on imaging

Healthcare providers also recommend screening for primary hyperaldosteronism in people with resistant hypertension (high blood pressure that doesn’t respond to treatment), those with an adrenal incidentaloma (a tumor found by accident on an imaging scan), or those with a family history of early-onset stroke.^[2]

Possible complications

If left untreated, primary hyperaldosteronism can lead to serious and potentially life-threatening complications. The excess aldosterone is toxic to the body and causes damage beyond just raising blood pressure.^[18] Studies show that people with primary hyperaldosteronism face a much higher cardiovascular risk compared to people with regular high blood pressure at the same level.^[6]

The high blood pressure and electrolyte imbalances caused by primary hyperaldosteronism increase your risk for:^[1][5]

• Heart attack or heart failure
• Stroke
• Irregular heartbeat (arrhythmia)
• Kidney failure
• Temporary paralysis or inability to move
• Diabetes and metabolic syndrome^[2]
• Atrial fibrillation^[2]

Research shows that compared to people with regular high blood pressure, those with primary hyperaldosteronism have a 10-fold increased risk of stroke, heart attack, and heart rhythm problems.^[18]

How is it diagnosed?

Diagnosing primary hyperaldosteronism involves several steps. Healthcare providers typically start with blood tests and may need additional testing to confirm the diagnosis and determine the specific cause.^[1]

The initial screening test measures the levels of aldosterone and renin (an enzyme released by the kidneys) in your blood. These samples should be drawn in the morning for the most accurate results.^[5] Doctors calculate the aldosterone-to-renin ratio (ARR). In primary hyperaldosteronism, aldosterone levels are high while renin levels are low or undetectable. A ratio greater than 20:1 strongly suggests primary hyperaldosteronism.^[2][5]

Because some blood pressure medications can interfere with these tests, your doctor may ask you to stop certain medications for 4 to 6 weeks before testing.^[5] Blood tests will also check your potassium levels, though these may be normal in many people with the condition.^[1]

If screening tests suggest primary hyperaldosteronism, confirmatory tests may be needed. These tests try to lower aldosterone production either by giving medication or providing extra salt through diet or intravenous fluids. If aldosterone remains high after these challenges, the diagnosis is confirmed.^[5]

Once primary hyperaldosteronism is confirmed, medical imaging helps determine the underlying cause. A CT scan (computed tomography scan) or MRI scan (magnetic resonance imaging) can show whether there is a tumor or enlargement in one or both adrenal glands.^[1]

In some cases, a specialized procedure called adrenal venous sampling (AVS) may be performed. An experienced radiologist uses a catheter to take blood samples directly from both adrenal glands to measure how much aldosterone each gland is producing. This helps determine whether one gland or both are overactive, which is important for deciding on treatment.^[4]

Treatment options

Treatment for primary hyperaldosteronism depends on the underlying cause. The main goals are to normalize blood pressure, correct potassium and other electrolyte levels, bring aldosterone levels back to normal, and reduce the risk of complications.^[8]

Surgery

When primary hyperaldosteronism is caused by a tumor in one adrenal gland or when only one gland is overactive, surgery is often the preferred treatment. The procedure, called adrenalectomy, removes the affected adrenal gland and any tumor. This is typically done using minimally invasive techniques and takes about 20 to 30 minutes.^[18]

Surgery can often permanently resolve the condition. While hypertension is frequently cured after surgery in patients with a single aldosterone-producing tumor, the average cure rate is about 33% when considering all surgical cases.^[8] Even when blood pressure isn’t completely cured, surgery typically makes it much easier to control with fewer medications.

Medication

Medical treatment is recommended for people who are not candidates for surgery, those who have both adrenal glands affected, or those who choose not to have surgery. The main medications used are called mineralocorticoid receptor antagonists (MRAs), which block the effects of aldosterone.^[2]

Two medications are currently available for treating primary hyperaldosteronism:

• Spironolactone – This medication can cause side effects in some people, including breast tenderness in men and menstrual irregularities in women, because it also blocks other hormone receptors.^[8]
• Eplerenone – This is a more selective medication that typically causes fewer hormonal side effects than spironolactone.^[8]

These medications are often combined with other blood pressure medications and sometimes with thiazide diuretics (water pills) for better blood pressure control.^[8] Some people with familial hyperaldosteronism may be treated with a steroid medication called dexamethasone.^[6]

Lifestyle changes

Regardless of whether you have surgery or take medication, lifestyle adjustments are an important part of managing primary hyperaldosteronism. A low-salt diet is particularly helpful, such as following the DASH diet (Dietary Approaches to Stop Hypertension).^[6] Other healthy lifestyle habits include maintaining a healthy weight, being physically active, reducing stress, and limiting alcohol intake.^[13]

Outlook with treatment

The outlook for people with primary hyperaldosteronism is generally excellent when the condition is properly diagnosed and treated. Prompt treatment can successfully manage the condition and prevent or reduce complications.^[1]

Treatment improves blood pressure control and helps protect against cardiovascular problems. Studies show that targeted therapy reduces cardiovascular morbidity and improves outcomes.^[2] Even when blood pressure isn’t completely normalized, treatment significantly reduces the risk of heart disease, stroke, kidney damage, and other serious complications.

It’s important for all physicians who treat high blood pressure to screen appropriate patients for primary hyperaldosteronism, as early detection and treatment make a significant difference in long-term health outcomes.^[2] However, studies show that fewer than 5% of patients who should be screened are actually evaluated for this condition, meaning many people go undiagnosed.^[18]