Hyperaldosteronism

Summary

• Aldosterone is part of the renin: aldosterone system that retains Na+ and water to maintain organ perfusion

• Hyperaldosteronism is a sign of raised aldosterone

• Commonest causes are Conn's Syndrome (20%) and bilateral adrenal hyperplasia (70%)

• Presentation: treatment resistant hypertension, Na+ upper limit of normal, hypokalaemia, alkalosis

• Assessment: renin, abdominal CT +/- MRI or PET/ SPECT

Outline

Assessment 

Presentation

• Treatment resistant hypertension

Investigations

• Na + 140-145

• K+ 3.0-4.0

• Raised aldosterone

• Renin- will dictate whether adrenal or non-adrenal issue 

Diagnosis

Hyperaldosteronism: raised aldosterone levels in blood serum

Management: 

1. Assess underlying cause 

Renin: aldosterone ratio. 

Stop ACEi, ARB prior to renin: aldosterone test. 

MRI is more sensitive than CT for adrenal adenoma. 

Venous sampling can be used to detect which side the adrenal adenoma is on. 

2. Management as per underling cause

Differentials

Primary Hyperaldosteronism (source- adrenal gland)

1. Conn's Syndrome

   • Commonest cause of hyperaldosteronism

   • Adrenal adenoma, secrets aldosterone 

   • Investigations

     1. Low renin, raised aldosterone

     2. CTAP imaging- locates growth

2. Bilateral adrenal hyperplasia

   • 20% of hyperaldosteronism

   • Adrenal hyerpplasia secrets aldosterone 

   • Investigations

     1. Low renin, raised aldosterone

     2. CTAP imaging shows bilateral adrenal enlargement

3. Unilateral adrenal hyperplasia

   • 10% of hyperaldosteronism

Secondary hyperaldosteronism (source- not adrenal gland)

Reduction in blood flow causing renin secretion and aldosterone production

1. Renal tumour

2. Renal artery stenosis

3. OSA, nephrotic syndrome, hepatic cirrhosis, CHF, 

4. Bartter or Gitelman Syndromes

Pseudohyperaldosteronism

1. Liddle syndrome

3. • Not a true source of hyperaldosteronism

   • Although presents with HTN, hypokalaemia & raised renin/ aldosterone

   • Presentation: under 18yrs

2. Liquorice abuse

3. • Liquorice has a compound, Glycyrrhiza, that mimics aldosterone

   • Inhibits 11-B-HSD which converts cortisol to cortisone, result: rise in cortisol which binds to aldosterone receptor

   • Presentation: HTN, hypokalaemia, renin & aldosterone low

3. SAME

3. • Syndrome of apparent mineralocorticoid excess

   • Presentation: hypertension with hypokalaemia metabolic alkalosis, with low renin: aldosterone

   • Elevated cortisol: cortisone ratio -> producing HTN

References and Resources

1. Woo K, Waisman J, Melamed J, Lepor H. Primary aldosteronism caused by unilateral adrenal hyperplasia. Rev Urol. 2000 Spring;2(2):100-4. PMID: 16985748; PMCID: PMC1476104.

Written in 2025.