Primary Hyperaldosteronism

Question 1

Define Primary Hyperaldonsteronism?

Answer 1

Characterised by autonomous aldosterone overproduction from the adrenal gland with subsequent suppression of plasma renin activity

Question 2

What is the common aetiology of Primary Hyperaldonsteronism?

Answer 2

Adrenal adenoma (Conn's Syndrome) - responsible for 70% of cases
Adrenal Cortex Hyperplasia (30% of cases)

Question 3

What are the rarer causes of Primary Hyperaldonsteronism?

Answer 3

Glucocorticoid-suppressible hyperaldosteronism

Aldosterone producing adrenal carcinoma

Question 4

What is the pathophysiology of Primary Hyperaldonsteronism?

Answer 4

Excess aldosterone leads to increased Na+ and water retention
This leads to hypertension
It also causes increased renal K+ loss leading to hypokalaemia
Renin is suppressed due to NaCl retention

Question 5

What is the epidemiology of Primary Hyperaldonsteronism?

Answer 5

1-2% of hypertensive patients
Conn’s Syndrome is more common in WOMEN and YOUNG patients
Bilateral adrenal hyperplasia is more common in MEN and presents at an older age

Question 6

What are the presenting symptoms of Primary Hyperaldonsteronism?

Answer 6

Usually Asymptomatic
Tends to be an incidental finding on routine blood tests
Symptoms of Hypokalaemia

Question 7

What are the symptoms of Hypokalaemia?

Answer 7

Muscle weakness
Polyuria and polydipsia (due to nephrogenic DI)
Paraesthesia
Tetany

Question 8

What are the signs of Primary Hyperaldonsteronism on physical examination?

Answer 8

Hypertension

Complications of Hypertension (e.g. hypertensive retinopathy)

Question 9

What are the two types of tests you would do to investigate Primary Hyperaldonsteronism?

Answer 9

Screening Tests

Confirmatory Tests

Question 10

What Screening Tests would you do for Primary Hyperaldonsteronism?

Answer 10

Low Serum K+
High Urine K+
High Plasma Aldosterone Concentration
High aldosterone: renin activity ratio

Question 11

Why do we not investigate Serum Na+ for Primary Hyperaldonsteronism?

Answer 11

Serum Na+ is usually normal because the Na+ reabsorption is matched by water reabsorption

Question 12

What confirmatory tests would you do for Primary Hyperaldonsteronism?

Answer 12

Salt Loading
Postural Test 
CT/MRI
Bilateral Adrenal Vein Catheterisation
Radio-labelled Cholesterol Scanning

Question 13

Why do we do Salt Loading for Primary Hyperaldonsteronism?

Answer 13

Failure of aldosterone suppression following salt load confirms Primary Hyperaldonsteronism

Question 14

What happens in the Postural Test for Primary Hyperaldonsteronism?

Answer 14

Measure plasma aldosterone, renin activity and cortisol when the patient is lying down at 8 am
Measure again after 4 hrs of the patient being upright

Question 15

What results might we see for the Postural Test in some of the different forms of Primary Hyperaldonsteronism?

Answer 15

Aldosterone-producing Adenoma - Aldosterone secretion decreases between 8 am and noon
Bilateral adrenal hyperplasia - adrenals respond to standing posture and increase renin production leading to increased aldosterone secretion

Question 16

What does Bilateral Adrenal Vein Catheterisation do and why do we do to investigate Primary Hyperaldonsteronism?

Answer 16

Measures adrenal vein aldosterone levels and allows you to distinguish between Conn’s Syndrome and bilateral adrenal hyperplasia

Question 17

What might we see in Radio-labelled cholesterol scanning for Primary Hyperaldonsteronism?

Answer 17

Unilateral uptake in adrenal adenomas

Bilateral uptake in bilateral adrenal hyperplasia

Question 18

What is the management plan for Bilateral Adrenal Hyperplasia?

Answer 18

Spironolacotone
Eplerenone can be used if the spironolactone side-effects are intolerable
Amiloride (potassium-sparing diuretic)
Monitor Serum K+, creatinine and BP
ACE inhibitors and CCBs may also be added

Question 19

What is the management plan for Aldosterone Producing Adenomas?

Answer 19

Adrenalectomy

Question 20

What is the management plan for Adrenal Carcinoma?

Answer 20

Surgery

Post-operative mitotane (antineoplastic)

Question 21

What are the possible complications for Primary Hyperaldonsteronism?

Answer 21

Complications of hypertension

Question 22

What is the prognosis for patients with Primary Hyperaldonsteronism?

Answer 22

Surgery may cure hypertension

Or it may make the hypertension easier to treat with anti-hypertensive medication