Endocrinology - Hyperaldosteronism Flashcards
What does angiotensin 2 do?
Stimulates the release of aldosterone from the adrenal glands which raises BP
Angiotensin 2 on its own also raises BP
What is the function of Aldosterone?
Acts on the kidney to:
- Increase sodium reabsorption from the distal tubule
- Increase potassium secretion from the distal tubule
- Increase hydrogen secretion from the collecting ducts
What is primary hyperaldosteronism?
Conn’s syndrome
Adrenal glands produce excess aldosterone
Serum renin is low (as suppressed by high blood pressure)
What are the possible causes of Primary hyperaldosteronism?
An adrenal adenoma secreting aldosterone (most common)
Bilateral adrenal hyperplasia
Familial hyperaldosteronism type 1 and type 2 (rare)
Adrenal carcinoma (rare)
What is secondary hyperaldosteronism?
Excessive renin stimulating the adrenal glands to produce more aldosterone
Serum renin is high
Causes of secondary hyperaldosteronism
When the BP in the kidneys is lower than the BP in the rest of the body
Renal artery stenosis - (cause to remember)
Renal artery obstruction
Heart failure
What is renal artery sclerosis? What causes it? Investigations?
Narrowing of the renal artery
Usually due to atherosclerosis
Doppler ultrasound, CTA or MRA
Investigations in suspected hyperaldosteronism
Check renin and aldosterone levels
Calculate a renin/aldosterone ratio
BP (hypertension) Serum electrolytes (hypokalaemia) Blood gas (alkalosis)
If aldosterone level high, look for cause:
- CT/MRI to look for adrenal tumour
- Renal doppler ultrasound or CT angio for renal artery stenosis/obstruction
Management of hyperaldosteronism
Aldosterone antagonists:
- Eplerenone
- Spironolactone
Treat underlying cause:
- Surgical removal of adenoma
- Percutaneous renal artery angioplasty for renal artery stenosis
If a patient is not responding to treatment for suspected essential hypertension…
Consider that it may be secondary hypertension
Perform a renin:aldosterone ratio
Hyperaldosteronism is the most common cause of secondary hypertension