- Primary hyperatdoteronisim is excess production of aldosterone,
- independent of renin-angiotensin ‘system.
- Consider this when the following features are present: hypertension.
- hypokalaemia, alkalosis in someone not on diuretics.
- Sodium tends to be mildly raised or normal.
- >50% due to unilateral adrenocortical adenoma (Conn’s syndrome).
- bilateral adrenocortical hyperplasia:
- adrenal carcinoma (rare);
- glucocorticoids- remediable aldosteronism (Or in GRA) In GRA the ACTH regulatory element of the 11 b-hydroxyiase gene fuses to the aldosterone syntheses gene increasing aldosterone production.
- and bringing it under the control of ACTI.
- U & E (when not on diuretics, hypotensives.
- steroids, K or ‘laxatives for 4 wks): don’t rely on a low K+ (30% are normokalaemic) ↑one and ↓renin – normal or high renin excludes the diagnosis.
- The differential diagnosis relies on assessing the effect of posture on renin, aldosterone, and cortisol (measure at 9AM lying, and at noon standing).
- If ↓ cortisol and aldosterone on standing:
- ACTH - dependents , ie Conn’s or GRA.
- If ↓cortisol and aldosterone↑ : angotensin II –dependent – ie hyperplasia.
- Do abdo CT/MRI for primary hyperaldosteronism to localize tumour.
- For (suspect particularly f family history of early hypertension) genetic testing is available.
- NB renal artery stenos is a more common cause of refractory ↑ BP and ↓K+.
- Evaluate with renal Dopplers. captopril renogram.
- or angiography (the gold standard).
- Surgery spironolactone up to 300mg/24h po for 4 weeks pre- op Hyperplasi : Spironolactone or amiloride.
- dexamethasone lmg/24h po for 4 weeks,
- normalizes biochemistry but not always BP.
- Due to a high renin (eg from renal artery stenosis.
- accelerated hypertension,
- This is a major cause of congenital (recessive) salt
- wasting - via a CC leak un the loop of Henle.
- Presents in childhood with failure to thrive ,
- BP is normal and there is no oedema.
- Look for hypokalaemia, hyochloraemic metabolk alkalosis, and ↑urinary K+ and Cl- ,
- Treatment include K+ replacement, NSAIDs amiloride, captopril.