Treatment of Conn's Syndrome
Fig.1: Specimen of a Conn's tumour within the adrenal glandSurgery
Surgery is indicated in the following situations:
- unilateral adrenal adenoma
- unilateral adrenal hyperplasia
- unilateral adrenocortical carcinoma
- familial hyperaldosteronism type II
The surgical option of choice for treatment of unequivocal adrenal adenoma is laparoscopic (keyhole surgery) removal of the affected gland - laparoscopic adrenalectomy (Fig. 1).
Ideally this should involve only partial adrenalectomy where possible, with selective excision of the tumour alone, preserving the rest of the adrenal tissue. This procedure does not have a higher recurrence rate than removal of the whole adrenal gland and has the virtue of preserving normal adrenal tissue.
Laparoscopic adrenalectomy is not suitable for suspected carcinoma however, which should be removed via a traditional open operation.
Surgery is not used in other causes of primary hyperaldosteronism, where medical therapy with spironolactone is preferred (surgical cure in bilateral adrenal hyperplasia is less than 20%).
Preceding surgery, medical therapy such as spironolactone and amiloride (see below) should be given for 4-6 weeks to control blood pressure and replenish potassium stores. Good blood pressure control preoperatively results in a better long-term outcome.
More detail about laparoscopic adrenal surgery can be found on the main Adrenal Surgery webpage.
Postoperative outcome
Removal of an aldosterone-producing adenoma will return the potassium level to normal in 95% of patients almost immediately. Hypertension is improved in 75% within a month of adenalectomy; of these, one third will come off all antihypertensive tablets, two thirds will require fewer medications than before the surgery.
Long term cure of hypertension is only achieved in 30-60% of patients however, probably due to underlying essential hypertension and pathological damage to blood vessels due to longstanding elevated blood pressure from prior excess aldosterone.
Postoperatively, blood tests are carried out to check the levels of potassium, renin and aldosterone to assess the surgical result.
Medical Treatment
This is used perioperatively to control blood pressure and potassium prior to surgery, but is also indicated in patients with:
- tumours unsuitable for surgery
- bilateral idiopathic adrenal hyperaldosteronism
- glucocorticoid-suppressible aldosteronism (GSA)
Spironolactone
Fig.2: Spironolactone bodies (arrowed)An antagonist of aldosterone (i.e. it blocks aldosterone's actions), it corrects potassium levels quickly and blood pressure and blood pH less quickly. In high doses it can inhibit testosterone production causing gynaecomastia (breast development in men), reduced libido and impotence in men, and irregular periods in women.
After treatment with spironolactone, the histology of the tumour will show evidence of its use by the formation of ‘spironolactone bodies’, visible on light microscopy (Fig. 2).
Amiloride™
A potassium sparing-diuretic, it is used when patients are intolerant of spironolactone. It can rarely cause headaches, lethargy and nausea.
Dexamethasone
This is a glucocorticoid used to suppress ACTH release from the pituitary (see 'Function' webpage), and is used preferentially in glucocorticoid-suppressible aldosteronism (GSA).
Other drugs
- antihypertensives - (drugs lowering blood pressure)
- ACE inhibitors - specifically for IHA which is very sensitive to angiotensin II.