Conn's syndrome (Primary hyperaldosteronism)

Question 1

What is the definition of Conn’s syndrome? [4]

Answer 1

primary hyperaldosteronism / refers to the excess production of aldosterone / independent of the renin-angiotensin-aldosterone system (RAAS) / increased Na+ and water retention, decreased renin release

Question 2

What is the aetiology of primary hyperaldosteronism? [2]

Answer 2

1. 2/3 due to solitary aldosterone-producing adrenal adenoma (Conn’s syndrome)
2. 1/3 due to bilateral adrenocortical hyperplasia

Question 3

What is the aetiology of secondary hyperaldosteronism? [2]

Answer 3

1. due to excess renin release, and hence angiotensin II which stimulates aldosterone release
2. from decreased renal perfusion, e.g. in renal artery stenosis, accelerated hypertension, diuretics, congestive cardiac failure or hepatic failure

Question 4

What are the risk factors of primary hyperaldosteronism? [4]

Answer 4

Hypertension in patients -

1. <35 years of age with no family history of hypertension
2. hypokalaemia before diuretic therapy
3. accelerated (malignant) hypertension
4. resistant to conventional antihypertensives

Question 5

What is the pathophysiology of primary hyperaldosteronism? [3]

Answer 5

1. disorder of the adrenal cortex characterised by excess aldosterone production
2. leading to increased Na+ and water retention, with low K+
3. combination of hypokalaemia and hypertension due to aldosterone-producing adenoma (Conn’s syndrome) or bilateral adrenocortical hyperplasia

Question 6

What are the symptoms of primary hyperaldosteronism? [6]

Answer 6

1. often asymptomatic

signs of hypokalaemia -

2. weakness
3. cramps
4. paraesthesia
5. polyuria and polydipsia
6. hypertension due to increase in blood volume

Question 7

How can primary hyperaldosteronism be diagnosed? [4]

Answer 7

1. serum hypokalaemia
2. hypokalaemia on ECG - flat T waves, ST depression, long QT
3. plasma aldosterone: renin ratio - aldosterone is much higher
4. increased plasma aldosterone levels that are not suppressed with 0.9% saline infusion or fludrocortisone administration

Question 8

What is the treatment for primary hyperaldosteronism? [2]

Answer 8

1. laparoscopic adrenalectomy

2. aldosterone antagonists, e.g. oral spironolactone