Conn's syndrome

Question 1

Define Conn’s syndrome

Answer 1

Conn’s syndrome = primary hyperaldosteronism. It is when the adrenal glands are producing too much aldosterone

Question 2

Describe the renin-angiotensin-aldosterone system

Answer 2

When blood pressure is low:

• Juxtaglomerular cells in the kidneys release an enzyme called renin
• The liver releases angiotensinogen
• Renin converts angiotensinogen to angiotensin I
• Angiotensin I is converted to Angiotensin II via ACE enzyme in the lungs
• Angiotensin II stimulates the adrenal glands to secrete aldosterone

Question 3

Describe aldosterone and its main effects on the body

Answer 3

Aldosterone is a mineralocorticoid steroid hormone that aims to increase blood pressure. It does this by acting on the kidney:

• Increases sodium reabsorption in the distal tubule
• Increases potassium secretion in the distal tubule
• Increases hydrogen secretion in the collecting duct

Question 4

Define the two types of hyperaldosteronism

Answer 4

1. ) Primary (aka Conn’s syndrome): when an adenoma is secreting additional aldosterone
2. ) Secondary: when excess renin is secreted causing excessive aldosterone to be secreted

Question 5

Define the risk factors for Conn’s syndrome

Answer 5

HTN

Question 6

Describe the pathology of the two types of hyperaldosteronism

Answer 6

• Conn’s syndrome: when an adenoma present on the adrenal gland produces excess aldosterone, resulting in a high blood pressure. Get K+ loss, Na+ and water retention: all raise blood pressure. Also get decreased rein release and hypokalaemia
• Secondary: when there is renal stenosis, so the kidney detects low BP, resulting in more renin being produced, so more aldosterone is produced to increase B.P. but due to stenosis, kidneys continue to detect a low B.P

Question 7

Describe the cause of hyperaldosteronism

Answer 7

1. ) Adrenal adenoma
2. ) Adrenal carcinoma
3. ) Renal artery obstruction/stenosis
4. ) Familial hyperaldosteronism
5. ) Bilateral adrenal hyperplasia

Question 8

Describe the signs and symptoms

Answer 8

Signs

1. ) High blood pressure/Hypertension
2. ) Metabolic alkalosis
3. ) Increased risk of cardiac arrthymias

Symptoms

1. ) Usually asymptomatic
2. ) Symptoms of hypokalaemia: constipation/muscle weakness/polyuria/polydipsia/paraesthesia

Question 9

How would you investigate and diagnose hyperaldosteronism

Answer 9

1. ) U&Es: Aldosterone ratio
   - Primary: Low renin + high aldosterone
   - Secondary: High renin + high aldosterone
2. ) Blood test: low potassium
3. ) Arterial blood gas: shows alkalosis
4. ) If suspected primary: MRI/CT to diagnose adenoma
5. ) ECG:
   - Flat T waves
   - ST depression
   - Long QT intervals
   - Long PR intervals
   - Pathological U waves
6. ) If suspected secondary: doppler/MRCA/angiogram to detect renal artery obstruction

Question 10

Describe the management of hyperaldosteronism

Answer 10

1. ) Primary: surgical removal of adenoma: laparoscopic adrenalectomy
2. ) Oral spironolactone - aldosterone antagonist (K+ sparing diuretic)

Secondary: fit a stent via the femoral artery