---
title: Primary aldosteronism
description: What primary aldosteronism (Conn syndrome) is, why too much aldosterone raises blood pressure and lowers potassium, why it matters for the heart, who is tested and how, which treatment approaches clinical guidelines describe, and when to call an ambulance.
type: disease
aliases:
  - primary hyperaldosteronism
  - hyperaldosteronism
  - Conn syndrome
  - Conn's syndrome
  - PA
  - aldosterone-producing adenoma
  - aldosteronoma
sources:
  - tier: guideline
    org: esc
    title: 2024 ESC Guidelines for the management of elevated blood pressure and hypertension
    year: 2024
    doi: 10.1093/eurheartj/ehae178
    url: https://doi.org/10.1093/eurheartj/ehae178
  - tier: guideline
    org: minzdrav-rf
    title: Артериальная гипертензия у взрослых
    year: 2024
    doi: 10.15829/1560-4071-2024-6117
    url: https://cr.minzdrav.gov.ru/view-cr/62_3
  - tier: reference
    org: msd-manuals
    title: Primary Aldosteronism (Conn Syndrome) (MSD Manual Professional Version)
    year: 2026
    url: https://www.msdmanuals.com/professional/endocrine-and-metabolic-disorders/adrenal-disorders/primary-aldosteronism
  - tier: reference
    org: msd-manuals
    title: Hyperaldosteronism (MSD Manual Consumer Version)
    year: 2026
    url: https://www.msdmanuals.com/home/hormonal-and-metabolic-disorders/adrenal-gland-disorders/hyperaldosteronism
  - tier: reference
    org: msd-manuals
    title: Hypertension (MSD Manual Professional Version)
    year: 2026
    url: https://www.msdmanuals.com/professional/cardiovascular-disorders/hypertension/hypertension
  - tier: reference
    org: statpearls
    title: Hyperaldosteronism
    year: 2025
    url: https://pubmed.ncbi.nlm.nih.gov/29763159/
  - tier: review
    title: 'Primary Aldosteronism: An Endocrine Society Clinical Practice Guideline'
    year: 2025
    doi: 10.1210/clinem/dgaf284
    url: https://doi.org/10.1210/clinem/dgaf284
sources_checked: 2026-10-14
review: null
---

Primary aldosteronism (primary hyperaldosteronism, Conn syndrome) is a condition in which the adrenal cortex makes too much of the hormone aldosterone on its own, without the usual control.<Cite n={[3, 6]} /> It is one of the common causes of secondary hypertension, that is, high blood pressure with a specific cause.<Cite n={[1, 5, 7]} /> For high blood pressure in general, see the article on [hypertension](../hypertension/).

The condition often goes unrecognised for years, even though there are good ways to find and treat it.<Cite n={[6, 7]} /> The 2024 European guidelines advise considering a test for it in all adults with confirmed high blood pressure.<Cite n={1} />

<Diagram name="primary-aldosteronism">
  <p slot="normal">
    The diagram shows a kidney with the adrenal gland on top of it. The adrenal gland makes
    aldosterone: this hormone makes the kidneys keep sodium, and water with it, and remove
    potassium.<Cite n={[3, 4]} /> Aldosterone production is controlled by renin from the kidney;
    when there is more sodium and fluid in the blood, less renin is released.<Cite n={[3, 4]} />
  </p>
  <p slot="disease">
    In primary aldosteronism the adrenal gland, for example because of a benign tumour (adenoma),
    makes aldosterone on its own, while renin is suppressed.<Cite n={[1, 3, 4]} /> Sodium and water
    are retained, the volume of blood in the vessels grows and blood pressure rises; potassium is
    lost in the urine, and its level in the blood may fall.<Cite n={[3, 4, 5]} /> The ESC lists
    atrial fibrillation among the signs of the condition, as well as damage to the heart and other
    organs that is greater than would be expected at that blood pressure.<Cite n={1} />
  </p>
</Diagram>

## Why it happens

<Patient>

The cause lies in the adrenal gland itself. It can be a benign tumour of one adrenal gland (adenoma) that makes aldosterone, or enlargement (hyperplasia) of both adrenal glands; adrenal cancer is rare.<Cite n={[1, 3]} /> Most cases are not inherited, but in some people the condition runs in the family.<Cite n={[1, 2]} />

Aldosterone can also be high for another reason, in response to high renin, for example when a kidney artery is narrowed. This is secondary hyperaldosteronism; see the article on [renal artery stenosis](../renal-artery-stenosis/).<Cite n={4} />

Regularly eating large amounts of real liquorice can cause a similar picture, but this is not hyperaldosteronism.<Cite n={[2, 4]} />

</Patient>

<Student>

PA is autonomous hypersecretion of aldosterone by the adrenal cortex (hyperplasia, adenoma or, rarely, carcinoma) with low renin.<Cite n={[3, 6]} /> In its pathophysiology box the ESC names aldosterone-producing adenoma, bilateral hyperplasia and familial forms due to germline mutations.<Cite n={1} /> According to the Russian Ministry of Health guideline, most cases are sporadic, but up to 5% of patients may have a familial form.<Cite n={2} /> Normally aldosterone secretion is regulated by the renin-angiotensin system (renin from the kidneys stimulates the adrenal glands through angiotensin) and, to a lesser extent, by ACTH; sodium and water retention increase blood volume and reduce renin secretion.<Cite n={[3, 4]} /> In secondary hyperaldosteronism both renin and aldosterone are high.<Cite n={[3, 4]} />

Sources estimate the frequency differently. The Russian Ministry of Health guideline gives a prevalence of PA among patients with hypertension of 5–15%, and in a note 3.2% to 12.7% in primary care, 1% to 30% in specialist centres and up to 20% in severe hypertension.<Cite n={2} /> According to MSD, PA occurs in approximately 10–20% of patients with resistant hypertension.<Cite n={5} />

</Student>

## Symptoms

<Patient>

Often the condition causes no symptoms, and its only sign is high blood pressure.<Cite n={[1, 3]} /> Blood pressure can be slightly or very high, and it is often hard to bring down with usual medicines.<Cite n={[3, 6]} />

The classic sign is low potassium in the blood, but potassium often stays normal.<Cite n={[3, 4]} /> Low potassium also often causes no symptoms, but it can cause muscle weakness, tingling, cramps and muscle spasms, and rarely episodes of temporary paralysis.<Cite n={[1, 4]} /> Strong thirst, passing large amounts of urine often, and constipation can occur.<Cite n={[2, 4]} /> Swelling (oedema) is uncommon with this condition.<Cite n={3} />

Too much aldosterone also matters for the heart. The ESC lists [atrial fibrillation](../atrial-fibrillation/) among the signs of the condition, as well as damage to the heart and other organs that is greater than would be expected at that blood pressure.<Cite n={1} /> According to the Endocrine Society guideline, the risk of heart and blood vessel complications is higher with this condition than with ordinary (primary) hypertension.<Cite n={7} />

</Patient>

<Student>

The ESC (Figure 13) lists: mostly asymptomatic course; spontaneous or diuretic-provoked hypokalaemia; atrial fibrillation and disproportionate hypertension-mediated organ damage (HMOD); muscle weakness and tetany; adrenal incidentaloma; family history of PA, early-onset hypertension and/or stroke.<Cite n={1} /> According to MSD, PA is suspected in patients with hypertension and hypokalaemia but is increasingly diagnosed in patients with normokalaemia and resistant hypertension.<Cite n={3} /> The Russian Ministry of Health guideline lists muscle weakness, polyuria, polydipsia and constipation among its clinical features.<Cite n={2} />

</Student>

## How it is diagnosed

<Patient>

Everyone with high blood pressure has their blood potassium and sodium checked: this helps doctors suspect secondary hypertension.<Cite n={[1, 2]} /> The main test for hyperaldosteronism measures aldosterone and renin in the blood and the ratio between them.<Cite n={[1, 2, 3]} />

The result is affected by the potassium level, the amount of salt in the diet and many blood pressure medicines, so the doctor interprets the test taking treatment into account and may adjust the treatment beforehand.<Cite n={[1, 2, 3]} /> Do not stop medicines on your own before the test.

If the test points to the condition, confirmatory tests are usually done, and then doctors find out whether one adrenal gland makes the extra aldosterone or both: for this a CT or MRI scan is done, and blood is often taken from the adrenal veins.<Cite n={[1, 3]} /> The answer decides the type of treatment.<Cite n={[3, 6]} />

</Patient>

<Student>

The 2024 ESC guidelines recommend screening for secondary hypertension in patients with suggestive signs and in all adults diagnosed with hypertension before the age of 40 (I B).<Cite n={1} /> Screening for PA by renin and aldosterone measurements should be considered in all adults with confirmed hypertension (≥140/90 mmHg; IIa B).<Cite n={1} /> The Endocrine Society (2025) also suggests screening everyone with hypertension by determining the aldosterone-to-renin ratio (ARR).<Cite n={7} /> The Russian Ministry of Health guideline points to PA in spontaneous or diuretic-induced hypokalaemia, hypertension combined with an adrenal incidentaloma or sleep apnoea, a family history of early-onset hypertension (before 40) or PA in first-degree relatives.<Cite n={2} />

The ARR is affected by potassium, sodium restriction or loading and many antihypertensive drugs; the ESC lists them in a separate table.<Cite n={1} /> According to MSD, the diagnostic ratio depends on the assay and its units and should be individualised, so thresholds are not given here.<Cite n={3} /> The next steps according to the ESC are confirmatory tests (for example, the saline suppression test), adrenal vein sampling or functional imaging and, where indicated, genetic testing; the Russian Ministry of Health guideline names early onset and family history as indications.<Cite n={[1, 2]} /> According to MSD, CT and MRI are relatively insensitive, so most patients need adrenal vein catheterisation for lateralisation.<Cite n={3} />

</Student>

## How it is treated

<Patient>

Treatment depends on whether one adrenal gland makes the extra aldosterone or both.<Cite n={[1, 6]} /> The doctor makes the decision together with the patient.

If the cause is a tumour of one adrenal gland, that gland is usually removed by keyhole (laparoscopic) surgery.<Cite n={[1, 3]} /> After the operation, potassium almost always returns to normal and blood pressure falls; in many people it returns to normal completely, without medicines.<Cite n={[3, 4]} />

If both adrenal glands are enlarged or surgery is not possible, medicines that block the action of aldosterone are prescribed.<Cite n={[1, 2]} /> Removing both adrenal glands is not recommended in this case: blood pressure often stays high, and without adrenal glands lifelong hormone treatment would be needed.<Cite n={[3, 4]} /> Medicines are chosen and prescribed by the doctor; do not start, stop or change medicines on your own.

The aim of this treatment is not only to lower blood pressure but also to reduce the risk of heart and blood vessel complications linked to the condition.<Cite n={7} />

</Patient>

<Student>

ESC: medical treatment is mineralocorticoid receptor antagonists (MRAs); surgical treatment is unilateral adrenalectomy.<Cite n={1} /> According to the Russian Ministry of Health guideline, steroidal MRAs are the drugs of choice in bilateral adrenal hyperplasia or in unilateral disease when surgery is not possible; they bind competitively to aldosterone receptors and block its effects.<Cite n={2} /> Specific drugs and doses are not given here. According to MSD, after removal of an adenoma potassium normalises and blood pressure falls in all patients; complete normalisation of blood pressure without antihypertensive treatment occurs in 50–70% of patients.<Cite n={3} /> In hyperplasia, 70% remain hypertensive after bilateral adrenalectomy, so surgery is not recommended.<Cite n={3} />

</Student>

## When to call an ambulance

High blood pressure, including in primary aldosteronism, can lead to a hypertensive crisis: a marked rise in blood pressure with acute organ damage, which is often life-threatening.<Cite n={[2, 3]} /> Its signs are described in the article on [hypertensive crisis](../hypertensive-crisis/); if they appear, call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK). The article on [atrial fibrillation](../atrial-fibrillation/) explains when an irregular, fast pulse needs urgent help.

As with any heart or blood vessel condition, call an ambulance for fainting, chest pain or severe breathlessness: this is the site's general safety rule, repeated at the bottom of every page.

<Quiz />