Aldosterone

Question 1

What is Conn’s syndrome?

Answer 1

Primary hyperaldosteronism

Question 2

Briefly describe primary hyperaldosteronism

Answer 2

Primary hyperaldosteronism is when the adrenal glands are directly responsible for producing too much aldosterone.

Question 3

What happens to serum renin in primary hyperaldosteronism

Answer 3

Serum renin will be low as it is suppressed by the high blood pressure.

Question 4

What are some 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?

What happens to serum renin?

Answer 5

Secondary hyperaldosteronism is where excessive renin stimulating the adrenal glands to produce more aldosterone.
Serum renin will be high.

Question 6

What is the cause of high renin levels?

Answer 6

There are several causes of high renin levels and they occur when the blood pressure in the kidneys is disproportionately lower than the blood pressure in the rest of the body:
Renal artery stenosis
Renal artery obstruction
Heart failure

Question 7

How is hyperaldosteronism diagnosed?

How will the results differ in primary and secondary?

Answer 7

Renin / aldosterone ratio:
High aldosterone and low renin indicates primary hyperaldosteronism
High aldosterone and high renin indicates secondary hyperaldosteronism

Question 8

What investigations can be done in hyperaldosteronism?

Answer 8

Blood pressure (hypertension)
Serum electrolytes (hypokalaemia)
Blood gas analysis (alkalosis)
Renin/aldosterone ratio
Investigate cause:
CT / MRI to look for an adrenal tumour
Renal doppler ultrasound, CT angiogram or MRA for renal artery stenosis or obstruction

Question 9

How is hyperaldosteronism managed?

Answer 9

Aldosterone antagonists:
Eplerenone
Spironolactone
Treat the underlying cause:
Surgical removal of adenoma
Percutaneous renal artery angioplasty via the femoral artery to treat in renal artery stenosis

Question 10

What is the significance of hyperaldosteronism in secondary hypertension?

Answer 10

Hyperaldosteronism is worth remembering as the most common cause of secondary hypertension. If you have a patient with a high blood pressure that is not responding to treatment consider screening for hyperaldosteronism with a renin:aldosterone ratio. One clue that could prompt you to test for hyperaldosteronism might be a low potassium however be aware that potassium levels may be normal.