Endocrinology - Hyperaldosteronism

Question 1

What does angiotensin 2 do?

Answer 1

Stimulates the release of aldosterone from the adrenal glands which raises BP

Angiotensin 2 on its own also raises BP

Question 2

What is the function of Aldosterone?

Answer 2

Acts on the kidney to:

• Increase sodium reabsorption from the distal tubule
• Increase potassium secretion from the distal tubule
• Increase hydrogen secretion from the collecting ducts

Question 3

What is primary hyperaldosteronism?

Answer 3

Conn’s syndrome

Adrenal glands produce excess aldosterone

Serum renin is low (as suppressed by high blood pressure)

Question 4

What are the possible causes of Primary hyperaldosteronism?

Answer 4

An adrenal adenoma secreting aldosterone (most common)

Bilateral adrenal hyperplasia

Familial hyperaldosteronism type 1 and type 2 (rare)

Adrenal carcinoma (rare)

Question 5

What is secondary hyperaldosteronism?

Answer 5

Excessive renin stimulating the adrenal glands to produce more aldosterone

Serum renin is high

Question 6

Causes of secondary hyperaldosteronism

Answer 6

When the BP in the kidneys is lower than the BP in the rest of the body

Renal artery stenosis - (cause to remember)
Renal artery obstruction
Heart failure

Question 7

What is renal artery sclerosis? What causes it? Investigations?

Answer 7

Narrowing of the renal artery

Usually due to atherosclerosis

Doppler ultrasound, CTA or MRA

Question 8

Investigations in suspected hyperaldosteronism

Answer 8

Check renin and aldosterone levels

Calculate a renin/aldosterone ratio

BP (hypertension)
Serum electrolytes (hypokalaemia)
Blood gas (alkalosis)

If aldosterone level high, look for cause:

• CT/MRI to look for adrenal tumour
• Renal doppler ultrasound or CT angio for renal artery stenosis/obstruction

Question 9

Management of hyperaldosteronism

Answer 9

Aldosterone antagonists:

• Eplerenone
• Spironolactone

Treat underlying cause:

• Surgical removal of adenoma
• Percutaneous renal artery angioplasty for renal artery stenosis

Question 10

If a patient is not responding to treatment for suspected essential hypertension…

Answer 10

Consider that it may be secondary hypertension

Perform a renin:aldosterone ratio

Hyperaldosteronism is the most common cause of secondary hypertension