Young Hypertension/ Primary Hyperaldosteronism

What causes primary hyperaldosteronism?

Primary hyperaldosteronism develops when one or both adrenal glands produce aldosterone in an uncontrolled way. The most common causes are:

• Aldosterone-producing adenoma —a benign (non-cancerous) growth in one adrenal gland that makes excessive aldosterone. 
• Bilateral adrenal hyperplasia — an enlargement and overactivity of both adrenal glands without a distinct tumour.

Less common causes include a single enlarged adrenal gland without a visible tumour, cancer of the adrenal gland, or inherited forms where genetic changes cause the adrenal tissue to overproduce aldosterone.

Regardless of the cause, the overproduction is “primary” because it originates in the adrenal glands themselves, rather than being driven by another condition elsewhere in the body. Identifying the underlying cause is important, as treatment may differ depending on whether one or both glands are involved.

What are the signs and symptoms of primary hyperaldosteronism?

Primary hyperaldosteronism does not always cause obvious symptoms, and some people are diagnosed only after routine blood pressure checks or blood tests. The condition’s effects come mainly from two factors: raised blood pressure and low potassium levels.

Common signs and symptoms include:

• High blood pressure — often moderate to severe and sometimes resistant to standard medication. In younger adults, it may appear earlier than expected for essential hypertension.
• Low blood potassium (hypokalaemia) — not always present, but when it occurs it can cause:
  • Muscle weakness or cramps
  • Fatigue or low energy
  • Tingling sensations or numbness
  • Palpitations or irregular heartbeat

• Frequent urination and excessive thirst — caused by the body’s altered salt and water balance.
• Headaches or blurred vision — sometimes linked to persistently high blood pressure.

In many cases, people feel well and have no symptoms apart from raised blood pressure, which is why screening for primary hyperaldosteronism is important in certain groups, particularly younger patients with unexplained or resistant hypertension.

Who is at risk of primary hyperaldosteronism in Singapore? 

Primary hyperaldosteronism can occur in many different patient groups, but some are at a higher likelihood of having the condition. In Singapore, these risk factors are consistent with international guidelines, and recognising them is important for early detection and treatment.

• Sustained high blood pressure — people with consistently elevated blood pressure, particularly readings above 140/90 mmHg on several occasions, are more likely to have underlying primary hyperaldosteronism compared to those with mild hypertension.
• Resistant hypertension — this refers to blood pressure that remains above target despite taking three antihypertensive medicines, or blood pressure that can only be controlled with four or more medications. This group has a notably higher prevalence of primary hyperaldosteronism.
• Low potassium levels (hypokalaemia) — whether caused by the condition itself or triggered by diuretic use, low potassium alongside hypertension is a classic feature that should prompt testing.
• Adrenal incidentaloma — an adrenal mass found on scans done for unrelated reasons can sometimes be the source of excess aldosterone production, even in patients without obvious symptoms.
• Hypertension with sleep apnoea — obstructive sleep apnoea is linked to hormonal changes that may coexist with or worsen primary hyperaldosteronism, making screening advisable in this group.
• Family history of early-onset hypertension or stroke — having a close relative who developed high blood pressure or suffered a stroke before the age of 40 increases the likelihood of a genetic or inherited form of the condition.
• First-degree relatives of affected patients — close family members of someone diagnosed with primary hyperaldosteronism have a higher-than-average chance of having the condition themselves, even if they feel well.

What complications can arise if primary hyperaldosteronism is left untreated? 

Without proper treatment, primary hyperaldosteronism can lead to serious long-term health problems. Persistent excess aldosterone not only keeps blood pressure high but also directly damages the heart, blood vessels, and kidneys.

• Cardiovascular disease — long-standing high blood pressure and aldosterone excess increase the risk of heart attack, heart failure, atrial fibrillation, and stroke. These risks are higher than in people with essential hypertension of the same severity.
• Kidney damage — excess aldosterone can cause structural and functional changes in the kidneys, leading to chronic kidney disease and, in severe cases, kidney failure.
• Electrolyte imbalance — untreated hypokalaemia can result in muscle weakness, cramps, fatigue, and dangerous heart rhythm disturbances.
• Increased mortality — studies have shown that people with untreated primary hyperaldosteronism have higher rates of cardiovascular and kidney-related deaths compared to those with high blood pressure from other causes. Dr. Dinesh says Primary hyperaldosteronism confers a higher risk than usual and that makes the case for its detection and potential cure.
• Reduced quality of life — persistent symptoms such as headaches, palpitations, and muscle weakness can affect daily activities, work performance, and overall well-being. 

How is primary hyperaldosteronism diagnosed? 

Diagnosing primary hyperaldosteronism involves confirming that the adrenal glands are producing excess aldosterone and determining the underlying cause. This process usually takes place in stages, beginning with screening tests and followed by confirmatory assessments.

• Screening with aldosterone-to-renin ratio — a blood test measures the level of aldosterone and renin, then calculates the ratio between them. A high ratio, particularly when renin is suppressed, suggests autonomous aldosterone production and warrants further evaluation.
• Confirmatory testing — if the screening test is positive, additional tests are performed to confirm the diagnosis. These usually involve saline infusion. Each assesses whether aldosterone levels remain high when they should normally be suppressed.
• Identifying the source — once the diagnosis is confirmed, imaging such as a CT scan of the adrenal glands is used to check for adenomas or enlargement. However, imaging alone cannot always distinguish between unilateral and bilateral disease.
• Adrenal vein sampling — in many cases, blood samples are taken directly from each adrenal vein to compare aldosterone production between the two glands. This is commonly used for deciding whether surgery or medical therapy is more appropriate.
• Additional tests — blood tests to assess potassium levels and kidney function, as well as other hormonal measurements, may be done to guide treatment planning and monitor overall health.

What are the long-term effects of primary hyperaldosteronism?

If primary hyperaldosteronism is not diagnosed and treated early, the continued excess of aldosterone can have lasting effects on multiple organ systems. These effects result from both sustained high blood pressure and the direct harmful actions of aldosterone on the heart, blood vessels, and kidneys.

• Heart and blood vessels — chronic exposure to high aldosterone levels can cause thickening of the heart muscle (left ventricular hypertrophy), stiffening of blood vessels, and increased risk of heart rhythm problems such as atrial fibrillation. Over time, this significantly raises the chance of heart attack, stroke, and heart failure.
• Kidneys — excess aldosterone promotes scarring and loss of kidney tissue, leading to a gradual decline in kidney function. This may progress to chronic kidney disease, even in people whose blood pressure is well controlled later on.
• Metabolic changes — aldosterone excess may contribute to insulin resistance and impaired glucose metabolism, which could increase the risk of developing type 2 diabetes.
• Electrolyte-related problems — persistent low potassium can cause long-standing muscle weakness, fatigue, and in severe cases, irreversible heart rhythm disturbances.
• Overall life expectancy — people with untreated primary hyperaldosteronism have a higher risk of premature death from cardiovascular and kidney causes compared to those with other types of high blood pressure, making timely diagnosis and treatment essential.

What are the treatment options for primary hyperaldosteronism in Singapore? 

Treatment for primary hyperaldosteronism aims to correct the excess aldosterone production, normalise blood pressure, restore potassium balance, and reduce long-term cardiovascular and kidney risks. The approach depends on whether one or both adrenal glands are affected.

• Surgical removal (adrenalectomy) — if the excess aldosterone comes from a single adrenal gland, such as with an aldosterone-producing adenoma, surgery to remove the affected gland is often recommended. This can potentially cure the condition or significantly improve blood pressure control.
• Medication therapy — when both adrenal glands are overactive, or if surgery is not suitable, treatment involves medicines called mineralocorticoid receptor antagonists, such as spironolactone or eplerenone. These block the effects of aldosterone, helping lower blood pressure and maintain normal potassium levels.
• Lifestyle measures — reducing dietary sodium, maintaining a healthy weight, staying physically active, and following other heart-healthy habits can support medical or surgical treatment in controlling blood pressure.
• Monitoring and follow-up — regular check-ups, blood pressure monitoring, and periodic blood tests for potassium and kidney function are important to ensure the treatment remains effective and well-tolerated.

Summary 

Primary hyperaldosteronism is a hormonal condition where the adrenal glands produce excess aldosterone, leading to high blood pressure and sometimes low potassium levels. It can be caused by an adrenal growth, enlargement of one or both glands, or inherited factors, and is a significant cause of hypertension in younger adults. 

If you are experiencing persistent high blood pressure, especially at a young age, or have been told you have low potassium, schedule a consultation with us for a thorough assessment and tailored treatment plan.

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