Hyperaldosteronism

• Hyperaldosteronism refers to high levels of aldosterone
• Conn’s syndrome refers to an adrenal adenoma producing too much aldosterone
• Hyperaldosteronism may be present in 5-10% of patients with hypertension
• Hypertension is the key presenting feature of hyperaldosteronism, and many patients are otherwise asymptomatic
• Hyperaldosteronism may cause non-specific symptoms such as headaches, muscle weakness, and fatigue
• The Renin-Angiotensin-Aldosterone System


  Renin is an enzyme secreted by the juxtaglomerular cells in the afferent arterioles in the kidney. Renin converts angiotensinogen (released by the liver) into angiotensin I. Angiotensin I converts to angiotensin II in the lungs with the help of an enzyme called angiotensin-converting enzyme (ACE). Angiotensin II stimulates the release of aldosterone from the adrenal glands. Aldosterone acts on the nephrons in the kidneys to increase sodium reabsorption from the distal tubule, increase potassium secretion from the distal tubule, and increase hydrogen secretion from the collecting ducts
• Aldosterone


  • It is a mineralocorticoid steroid hormone that acts on the nephrons in the kidneys
• Primary Hyperaldosteronism


  • When the adrenal glands are directly responsible for producing too much aldosterone. Serum renin will be low as high blood pressure suppresses it. Possible causes include bilateral adrenal hyperplasia, an adrenal adenoma secreting aldosterone (Conn’s syndrome), and familial hyperaldosteronism
• Secondary Hyperaldosteronism


  • Caused by excessive renin stimulating the release of excessi
• Possible reasons for hyperaldosteronism

  • Bilateral adrenal hyperplasia (most common)
  • Adrenal adenoma secreting aldosterone (Conn’s syndrome)
  • Familial hyperaldosteronism (rare)
  • Secondary Hyperaldosteronism
• Secondary hyperaldosteronism is caused by

  Excessive renin stimulating the release of excessive aldosterone
• Excessive renin is released due to

  Disproportionately lower blood pressure in the kidneys, usually due to: Renal artery stenosis, Heart failure, Liver cirrhosis and ascites
• Renal artery stenosis


  Refers to a narrowing of the artery supplying the kidney, usually due to atherosclerosis, similar to the narrowing of the coronary arteries in angina
• Confirmation of renal artery stenosis

  1. Doppler ultrasound

  2. CT angiogram

  3. Magnetic resonance angiography (MRA)
• Investigations for hyperaldosteronism


  1. Aldosterone-to-renin ratio (ARR) is used as a screening test

  2. Other investigations include: Raised blood pressure (hypertension), Low potassium (hypokalaemia), Blood gas analysis (alkalosis)
• Investigations for underlying cause of hyperaldosteronism

  CT or MRI to look for an adrenal tumour or adrenal hyperplasia, Renal artery imaging for renal artery stenosis (Doppler, CT angiogram or MR angiography), Adrenal vein sampling of blood from both adrenal veins to locate which gland is producing more aldosterone
• Management of hyperaldosteronism


  Medical management with aldosterone antagonists: Eplerenone, Spironolactone, Treating the underlying cause involves: Surgical removal of the adrenal adenoma, Percutaneous renal artery angioplasty via the femoral artery to treat renal artery stenosis
• Hyperaldosteronism is the most common cause of secondary hypertension
• Consider testing for hyperaldosteronism in patients with hypertension, who are younger, fail to respond to treatment, or have low potassium
• Be aware that potassium levels may be normal in hyperaldosteronism