Primary Hyperaldosteronism

Question 1

What is Conn’s syndrome and what causes it?

Answer 1

Excess production of aldosterone by the adrenal glands due to:

• aldosterone secreting adenoma
• bilateral adrenal hyperplasia/idiopathic hyperaldosteronism= excessive Ag2 production
• familial hyperaldosteronism (type 1 and 2)
• adrenal carcinoma

Question 2

How can you differentiate between primary and secondary hyperaldosteronism?

Answer 2

Renin:aldosterone ratio I.e. aldosterone will be high in each
Primary= low renin due to high blood pressure detected in afferent arterioles causing decreased secretion

Secondary= high renin due to excessive production of renin

Question 3

How would someone with primary hyperaldosteronism present?

Answer 3

Weakness and fatigue
Hypokalaemia= excess loss
Polyuria, nocturia and polydipsia= due to hypokalaemic induced diabetes insipidus
Headaches= due to high BP
Tetany (involuntary contractions of muscles)= due to metabolic alkalosis
Hypertension= NOTE: hyperaldosteronism is the most common cause of secondary hypertension

Question 4

What biochemical changes would you expect to see with primary hyperaldosteronism?

Answer 4

Hypokalaemia
Metabolic alkalosis= increased hydrogen ion secretion from collecting duct leads to fall in serum hydrogen and apparent excess of HCO- i.e. alkalosis

Question 5

What are the cause of secondary hyperaldosteronism?

Answer 5

Excessively high renin levels due to:

• renal artery stenosis
• renal artery obstruction
• heart failure

I.e. when BP in the kidneys is disproportionately low to the BP in the rest of the body

Question 6

How is primary adrenal insufficiency diagnosed?

Answer 6

Measure renin/aldosterone ratio
-low renin and high aldosterone

Fludrocortisone suppression test

Blood gas analysis
-metabolic alkalosis

CT (indicated when aldosterone:renin ratio indicates primary hyeraldosteronism)
-looking for adrenal tumour or bilateral abnormalities

Question 7

How can primary hyperaldosteronism be treated?

Answer 7

For adenoma

• excision
• spironolactone= aldosterone antagonist

Idiopathic hyperplasia

• spironolactone
• bilateral adrenalectomy if not medically controlled

Low salt diet for both

Question 8

What characteristics of patients blood pressure would make you consider primary hyperaldosteronism?

Answer 8

Hypertension not responding to 3+ medications

Presenting with hypertension before 30 yo

Question 9

What investigations can be done to distinguish between unilateral and bilateral causes?

Answer 9

Adrenal vein sample
-compare the hormone levels in each
Uni= adrenal adenoma
Bi= bilateral adrenal hyperplasia