Hyperaldosteronism (primary)

Question 1

def of hyperaldosteronism

Answer 1

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

Question 2

aetiology of hyperaldosteronism

Answer 2

excess aldosterone may be secondary to:
1 adrenal adenoma (Conns syndrome) 70%
2 hyperplasia of the adrenal cortex 30%
3 glucocorticoid suppressible hyperaldosteronism 3%

excess aldosterone results in:

• high Na reabsorption & water retention causing HTN
• high K secretion & hypokalaemia
• suppression of renin because of nacl retention

Question 3

epi of hyperaldosteronism

Answer 3

prevalence in hypertensive patients is very low
aldosterone producing adenomas are more common in women & <50yrs
bilateral adrenal hyperplasia occurs more commonly in men & presents at an older age

Question 4

history of hyperaldosteronism

Answer 4

often asymptomatic
symptoms of hypokalaemia
-muscle weakness
-polyuria & polydipsia
-paraesthesia

Question 5

examination of hyperaldosteronism

Answer 5

HTN

Question 6

investigations performed in suspected hyperaldosteronism

Answer 6

screening tests
-decreased serum K (<4mmol/l) however normal serum Na due to parallel increase in the water content of the blood
-increased urine K
-increased plasma aldosterone concentration: plasma renin activity ratio
confirmatory tests
-salt loading (failure of aldosterone suppression following a salt load confirms primary hyperaldosteronism
-postural test (plasma aldosterone, renin activity & cortisol measured with patient lying flat in morning, after 4 hours standing up right the tests are repeated, ACTH sensitive adenomas cause aldosterone secretion to decrease from, bilateral adrenal hyperplasia, adrenals respond to standing posture by increasing renin & thus aldosterone secretion)
-CT/MRI to visualise adrenals
-bilateral adrenal vein catheterisation for distinction between conns & bilateral adrenal hyperplasia

Question 7

management of hyperaldosteronism

Answer 7

aldosterone producing adenomas
-adrenalectomy
bilateral adrenal hyperplasia
-spironolactone (aldosterone receptor anatagonist)
-change to eplerenone if spironolactone side effects are intolerable (gynaecomastia, impotence, menstrual irregularities)

Question 8

complications of hyperaldosteronism

Answer 8

HTN

Question 9

prognosis of hyperaldosteronism

Answer 9

surgery will cure 50% of HTN OR make it more responsive to anti-hypertensive therapy