What are the characteristics of primary hyperaldosteronism (Conn's syndrome)?

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From the Guidelines

Primary hyperaldosteronism (Conn's syndrome) is characterized by unilateral or bilateral adrenal lesions, with unilateral forms being amenable to surgical treatment and bilateral forms requiring lifelong medical treatment. The management of primary aldosteronism depends on its subtype, and diagnosis involves distinguishing between unilateral and bilateral primary aldosteronism through adrenal vein sampling or functional imaging with radiolabelled tracers 1.

Key Characteristics

  • Unilateral primary aldosteronism is typically treated with surgical removal of the offending adrenal gland, unless the patient is older or has co-morbidities of concern
  • Bilateral primary aldosteronism requires medical treatment, currently based on mineralocorticoid receptor antagonists (MRAs) such as spironolactone, with an effective dose of 50–100 mg once daily, titrated up to 300–400 mg once daily if necessary 1
  • Familial forms of primary aldosteronism, such as glucocorticoid-remediable primary aldosteronism, can be corrected with dexamethasone, usually with low doses that are free of glucocorticoid effects and can be safely used during pregnancy 1

Treatment Options

  • Surgical removal of the adrenal gland for unilateral primary aldosteronism
  • Medical treatment with MRAs, such as spironolactone or eplerenone, for bilateral primary aldosteronism
  • Genetic testing for germ-line mutations in familial forms of primary aldosteronism 1

Important Considerations

  • Regular monitoring of blood pressure and electrolytes during treatment
  • Potential need for potassium supplements initially
  • Importance of identifying primary hyperaldosteronism to improve blood pressure control and reduce cardiovascular complications associated with long-term aldosterone excess 1

From the FDA Drug Label

  1. 4 Primary Hyperaldosteronism Spironolactone tablets are indicated in the following settings: Short-term preoperative treatment of patients with primary hyperaldosteronism. Long-term maintenance therapy for patients with discrete aldosterone-producing adrenal adenomas who are not candidates for surgery Long-term maintenance therapy for patients with bilateral micro or macronodular adrenal hyperplasia (idiopathic hyperaldosteronism).

The characteristics of primary hyperaldosteronism (Conn's syndrome) are not explicitly described in the provided drug labels. However, the labels do mention the following settings where spironolactone is indicated:

  • Short-term preoperative treatment of patients with primary hyperaldosteronism
  • Long-term maintenance therapy for patients with:
    • Discrete aldosterone-producing adrenal adenomas who are not candidates for surgery
    • Bilateral micro or macronodular adrenal hyperplasia (idiopathic hyperaldosteronism) 2 No conclusion can be drawn about the characteristics of primary hyperaldosteronism.

From the Research

Characteristics of Primary Hyperaldosteronism (Conn's Syndrome)

The characteristics of primary hyperaldosteronism, also known as Conn's syndrome, can be summarized as follows:

  • It is a common cause of secondary hypertension associated with excess cardiovascular morbidities 3, 4
  • It is underdiagnosed due to the lack of specific, easily identifiable features and poor awareness among clinicians 3
  • It is characterized by excess aldosterone production, which can lead to cardiovascular toxicity, cardiac events, glomerular hyperfiltration, and bone/metabolic sequelae 4
  • The etiologies of primary hyperaldosteronism include unilateral (aldosterone-producing adenoma) and bilateral (micro- or macronodular hyperplasia) forms 4, 5
  • Somatic mutations drive autonomous aldosterone production in most adenomas, and germline mutations can cause rare familial forms of aldosteronism 3
  • The diagnosis of primary hyperaldosteronism involves a multistep process of screening, confirmatory testing, and subtype differentiation 3, 6

Diagnostic Features

Some key diagnostic features of primary hyperaldosteronism include:

  • Low serum potassium levels, although this is not a reliable marker and can miss about a third of cases 7
  • Elevated plasma aldosterone concentration to plasma renin activity ratio, which is widely accepted as the test of choice for screening 7
  • Autonomy of aldosterone secretion, which can be demonstrated by tests such as diurnal variations in aldosterone concentration and response to angiotensin II 7
  • Adrenal imaging and adrenal vein sampling to determine the etiology and lateralization of the lesion 5, 6

Treatment Options

Treatment options for primary hyperaldosteronism depend on the subtype and include:

  • Unilateral adrenalectomy for patients with unilateral disease, which can offer a cure and improve blood pressure control 3, 5
  • Mineralocorticoid receptor antagonists for patients with bilateral disease or those who are not surgical candidates 3, 5
  • Spironolactone as the drug of choice for medical treatment 7

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diagnosis and treatment of primary aldosteronism.

The lancet. Diabetes & endocrinology, 2021

Research

Primary Aldosteronism: Diagnosis and Management.

The American journal of the medical sciences, 2016

Research

Evaluation and Management of Primary Hyperaldosteronism.

The Surgical clinics of North America, 2019

Research

Primary hyperaldosteronism.

Annals of clinical biochemistry, 2003

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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