Primary hyperaldosteronism is a hormonal disorder that often hides behind persistent high blood pressure, quietly affecting millions of people worldwide while frequently going undiagnosed for years. Understanding this condition can help patients recognize warning signs early and seek proper medical care before serious complications develop.

What is Primary Hyperaldosteronism?

Primary hyperaldosteronism, also known as Conn’s syndrome, is a condition that develops when the adrenal glands produce too much of a hormone called aldosterone, which is a steroid hormone responsible for controlling the balance of sodium and potassium in the blood.^[1] The adrenal glands are small organs that sit on top of each kidney and are part of the body’s endocrine system, which produces hormones needed for everyday body functions.^[3]

When aldosterone levels become too high, the body retains more sodium and loses potassium, which leads to elevated blood pressure.^[4] This happens because aldosterone tells the kidneys to hold onto salt and release potassium from the blood. The increased salt causes blood pressure to rise.^[5] Unlike secondary hyperaldosteronism, where other medical conditions trigger excess aldosterone production, primary hyperaldosteronism stems from a problem within the adrenal glands themselves.^[1]

How Common is Primary Hyperaldosteronism?

Primary hyperaldosteronism used to be considered a rare disorder, but modern research has revealed it is far more common than previously thought.^[1] Today, medical experts estimate that between 5 to 10 percent of all adults with high blood pressure have this condition.^[1][3] Some research suggests the prevalence may be even higher in certain groups.

Among people with medication-resistant high blood pressure, meaning their blood pressure remains elevated despite taking three or more medications, experts estimate that as many as 25 percent may have primary hyperaldosteronism.^[3] This represents a significant portion of the hypertensive population. The condition appears to be more common in women than in men.^[1][3] Most people receive their diagnosis between the ages of 30 and 40, though it can affect individuals between 30 and 50 years old.^[1][4]

What Causes Primary Hyperaldosteronism?

Primary hyperaldosteronism develops when the adrenal glands produce excessive amounts of aldosterone due to problems within the glands themselves.^[1] This overproduction disrupts the body’s normal balance of water, sodium, blood volume, and blood pressure regulation.^[1]

The most common cause is the presence of benign, or noncancerous, tumors in one or both adrenal glands.^[1][4] These are called aldosterone-producing adenomas, and they account for about 35 percent of all primary hyperaldosteronism cases.^[6] When only one adrenal gland is affected by such a tumor, this specific presentation is sometimes called Conn’s syndrome.

Another major cause is bilateral adrenal hyperplasia, which means both adrenal glands have become enlarged or overactive.^[2][5] This condition accounts for approximately 66 percent of cases.^[6] The hyperplasia specifically affects a part of the adrenal gland called the zona glomerulosa.^[2]

Less common causes include inherited genetic disorders. Several types of familial hyperaldosteronism exist, classified as types I, II, and III.^[2][5] These are rare genetic syndromes that may cause both glands to be hyperactive.^[5] In very rare cases, adrenal cancer can cause the condition, though this is uncommon.^[1][4]

Who is at Risk for Primary Hyperaldosteronism?

Anyone can develop primary hyperaldosteronism, but certain groups of people face higher risks.^[1] Understanding these risk factors can help patients and healthcare providers identify who should be screened for the condition.

People with low blood potassium levels, known as hypokalemia, have an increased risk.^[1] Those who develop high blood pressure before age 30 are also at higher risk, as this early onset of hypertension can signal an underlying hormonal problem.^[1] Individuals whose high blood pressure requires three or more medications to manage should be considered at increased risk for primary hyperaldosteronism.^[1]

The presence of an adrenal tumor discovered during imaging for other reasons also indicates higher risk.^[1] People with resistant hypertension, meaning their blood pressure remains difficult to control despite multiple medications, should be screened, as this group has a particularly high prevalence of the condition.^[2] Additionally, those with a family history of early-onset stroke may have increased risk.^[2]

Common Symptoms and How They Affect Daily Life

The hallmark symptom of primary hyperaldosteronism is high blood pressure, which often proves resistant to standard treatments.^[1][4] Many patients find themselves taking four or more blood pressure medications without achieving adequate control.^[5] The hypertension itself typically causes no symptoms initially, which is why high blood pressure is sometimes called a “silent killer.”^[1]

However, it is important to note that while low blood potassium levels are classically described as a defining feature of primary hyperaldosteronism, most patients actually have normal potassium levels.^[2][6] Only about a quarter of people with the condition experience low potassium.^[6] When potassium levels do drop, this can cause a range of troublesome symptoms.

People with low potassium may experience significant muscle weakness, which can be severe enough to cause temporary paralysis in some cases.^[1][3] Muscle cramps and spasms are common complaints.^[1][4] Individuals may feel persistent fatigue that interferes with daily activities.^[1][4] Tingling and numbness sensations can occur.^[3]

Many patients report excessive thirst and frequent urination, needing to urinate more than usual throughout the day and night.^[1][5] Headaches are another common symptom, as are episodes of blurred vision and dizziness.^[1][3][5] Some people experience numbness as well.^[4][5]

Serious Complications Without Treatment

If primary hyperaldosteronism goes untreated, the persistently high blood pressure and electrolyte imbalances can lead to severe and potentially life-threatening complications.^[1] The condition causes more damage to organs than high blood pressure alone, making early detection and treatment crucial.^[1]

Cardiovascular complications are among the most serious risks. People with untreated primary hyperaldosteronism face significantly increased risks of heart attack and heart failure.^[1][4] The excess aldosterone is toxic to the cardiovascular system, causing damage beyond what would be expected from high blood pressure alone.^[6] Studies have shown that individuals with primary hyperaldosteronism have a tenfold increased risk of stroke, heart attack, and heart rhythm problems compared to people with similar blood pressure levels but no aldosterone excess.

Irregular heart rhythms, medically known as arrhythmias, can develop due to low potassium levels.^[1] These abnormal heart rhythms can be dangerous and may lead to atrial fibrillation.^[6] Kidney damage is another major concern, as the kidneys are directly targeted by excessive aldosterone.^[1] Over time, this can progress to kidney failure.^[1][4][5]

Stroke risk is markedly elevated in people with primary hyperaldosteronism.^[1][4][5] In severe cases, temporary paralysis or the complete inability to move can occur.^[1] The condition also increases the risk of developing diabetes and metabolic syndrome.^[6] These complications underscore why screening and early treatment are so important.

How Primary Hyperaldosteronism is Diagnosed

Diagnosing primary hyperaldosteronism involves a series of blood tests that measure hormone levels in the body.^[1] The process typically begins with screening tests, followed by confirmatory tests if initial results suggest the condition.

The first step is usually a blood test called the aldosterone-to-renin ratio, often abbreviated as ARR.^[2][5][6] This test measures the levels of aldosterone hormone and renin, which is an enzyme released by the kidneys that helps regulate blood pressure.^[4][5] Blood samples should ideally be drawn in the morning for the most accurate results.^[2][5]

In people with primary hyperaldosteronism, the aldosterone level will be high while renin will be low or undetectable.^[5] If the ratio exceeds 20 to 1, this strongly suggests that the adrenal gland is the primary source of excess aldosterone production.^[2] The potassium level may be low or normal.^[5]

When screening tests are positive, patients may undergo additional tests to confirm the diagnosis. These confirmatory tests attempt to lower the amount of aldosterone produced, either by giving a medication or providing extra salt through the diet or intravenous fluid.^[5] If the aldosterone level remains high and the renin level stays low after these tests, the diagnosis is confirmed.^[5]

Some blood pressure medications can interfere with these tests, so physicians may ask patients to stop certain medications for four to six weeks before testing.^[5] After the diagnosis is confirmed, medical imaging such as CT scans may be performed to determine the underlying cause and whether one or both adrenal glands are affected.^[6] A specialized procedure called adrenal venous sampling may be used to determine which gland is producing excess aldosterone, particularly when surgery is being considered.^[2]

Is Primary Hyperaldosteronism Preventable?

Currently, there are no known ways to prevent primary hyperaldosteronism from developing, as the condition typically results from spontaneous changes within the adrenal glands, including benign tumors or hyperplasia.^[1] The genetic forms of the condition are inherited and cannot be prevented through lifestyle measures.

However, early detection through screening can prevent the serious complications associated with untreated primary hyperaldosteronism. People at high risk should discuss screening with their healthcare providers. This includes individuals with resistant hypertension, those requiring multiple blood pressure medications, people with low potassium levels, and those diagnosed with high blood pressure before age 30.^[1][2]

Regular blood pressure monitoring is essential for everyone, as high blood pressure itself is often the first clue to the presence of primary hyperaldosteronism. Maintaining a healthy lifestyle with regular exercise, a balanced diet low in salt, stress management, and avoiding excessive alcohol can help manage blood pressure overall, though these measures alone will not cure primary hyperaldosteronism if it is present.^[1]

How the Body Changes with Primary Hyperaldosteronism

Understanding what happens inside the body when primary hyperaldosteronism develops helps explain why the condition causes such serious problems. The disease disrupts several interconnected systems that normally work together to maintain health.

Aldosterone normally plays an important role in regulating blood pressure through its effects on the kidneys and the renin-angiotensin-aldosterone system, a complex chain of hormone reactions.^[3] When aldosterone levels become too high, the hormone instructs the kidneys to retain sodium and excrete potassium.^[4] This causes sodium to accumulate in the blood while potassium is lost.

The retained sodium increases the amount of fluid in the bloodstream, which raises blood volume and blood pressure.^[1] At the same time, the loss of potassium can disrupt normal muscle and nerve function, since potassium is essential for these systems to work properly. This explains why people with low potassium experience muscle weakness, cramps, and abnormal heart rhythms.

Beyond these direct effects, excess aldosterone is directly toxic to several organs. Recent research has shown that aldosterone affects tissues beyond just the kidneys and colon, where it was traditionally thought to work. The hormone can damage the heart muscle directly, leading to stiffening and scarring that increases the risk of heart failure.^[6] Blood vessels can become damaged and less flexible, further contributing to high blood pressure and cardiovascular disease.

The kidneys themselves suffer repeated damage from constant exposure to high aldosterone levels.^[6] Over time, this can lead to permanent kidney damage and progressive loss of kidney function. The central nervous system may also be affected, potentially contributing to stroke risk. These widespread effects on multiple organ systems explain why primary hyperaldosteronism causes more complications than high blood pressure alone.