Health condition
Primary aldosteronism deep dive
Primary aldosteronism (Conn's syndrome) is the commonest curable cause of high blood pressure, affecting perhaps 1 in 10 hypertensives - yet most cases are never tested for; the screen is a simple aldosterone-renin ratio blood test.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
The symptoms to recognise, when to seek help, which specialist to see, and what treatment usually involves.
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Suspect it with resistant hypertension, hypertension with low potassium, an adrenal nodule, or early-onset high blood pressure
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Screening test: the aldosterone-to-renin ratio (ARR); confirmatory suppression testing follows
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Adrenal venous sampling distinguishes one-sided disease (curable by surgery) from two-sided disease (treated with spironolactone)
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It carries higher heart, stroke and kidney risk than ordinary hypertension of the same level
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Specialist: a consultant endocrinologist, working with radiology and adrenal surgery
Understanding the condition
What it is and what happens next.
What causes it, how it is diagnosed, and the treatment routes available in the UK.
What it is and how it feels
Aldosterone excess makes the kidneys retain salt and dump potassium, driving blood pressure that shrugs off standard tablets and quietly injuring heart, vessels and kidneys beyond what the numbers predict. It is startlingly common among people needing three or more antihypertensives, yet testing rates remain low, so most affected people are treated for decades as ordinary hypertension while the treatable cause goes unfound.
Diagnosis and treatment routes
The screen is the aldosterone-renin ratio, ideally with medication adjustments beforehand; positive screens are confirmed with suppression testing, then CT and adrenal venous sampling establish whether one gland or both are responsible. Unilateral disease is often cured by keyhole adrenalectomy; bilateral disease responds well to spironolactone or eplerenone. If your blood pressure is resistant or came with low potassium, ask about the ARR. NHS endocrinology waits commonly run 20-45+ weeks; a private endocrinologist can usually start testing within about two weeks.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a consultant endocrinologist. Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any of the emergency symptoms described above.
Frequently asked
Common questions about Primary aldosteronism deep dive.
Quick, plain-English answers to what people ask us most.
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What is primary aldosteronism?
Primary aldosteronism is a condition where the adrenal glands produce too much aldosterone, a hormone that regulates salt and water balance, leading to high blood pressure and, often, low potassium levels.
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What causes primary aldosteronism?
It's most commonly caused by a benign adrenal adenoma (a small, non-cancerous growth) or overactivity of both adrenal glands (bilateral adrenal hyperplasia), leading to excess aldosterone production.
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What are the symptoms?
High blood pressure, often difficult to control with standard medications, along with symptoms of low potassium such as muscle weakness, cramps, and excessive thirst or urination, are typical.
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Is primary aldosteronism serious?
Yes, beyond causing difficult-to-control high blood pressure, it's associated with an increased risk of cardiovascular complications compared with other causes of high blood pressure at similar levels, making accurate diagnosis important.
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Can primary aldosteronism be treated?
Yes, treatment depends on the cause: surgical removal of an adenoma can be curative, while medications that block aldosterone's effects are used for bilateral disease or when surgery isn't suitable.
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How is primary aldosteronism diagnosed?
Blood tests measuring aldosterone and renin levels (and their ratio) are the initial screening step, followed by confirmatory testing and imaging or specialised vein sampling to determine the exact cause and guide treatment.
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How common is primary aldosteronism?
It's more common than previously thought, representing a meaningful proportion of people with high blood pressure, particularly those with difficult-to-control hypertension or low potassium levels, which is why targeted screening is increasingly recommended.
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How long does treatment take to work?
Surgical treatment for a single adenoma often shows improvement in blood pressure and potassium levels within weeks, while medication for bilateral disease is typically effective within a similar timeframe once the right dose is established.
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Primary aldosteronism vs essential hypertension — what's the difference?
Essential hypertension is common high blood pressure without a single identifiable hormonal cause, while primary aldosteronism is a specific, treatable hormonal cause of high blood pressure, identified through specific blood tests, particularly important to consider in difficult-to-control cases.
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When should I see a specialist, and how quickly can I be seen privately?
See an endocrinologist if you have difficult-to-control high blood pressure or low potassium levels. Private specialist assessment is typically available within about two weeks, considerably faster than standard NHS endocrine referral waiting times.