Primary hyperaldosteronism Flashcards
What is primary hyperaldosteronism characterised by
an excessive autonomous secretion of aldosterone resulting in a suppression of plasma renin activity
What are the 2 main causes of primary hyperaldosteronism
Unilalateral adenoma secreting excess aldosterone (70%)
Bilateral hyperplasia of the adrenal cortex (30%)
What is secondary hyperaldosteronism due to
Increased plasma renin activity and may be seen in conditions associated with reduced renal perfusion such as renal artery stenosis, congestive cardiac failure and cirrhosis
What sex does aldosterone-producing adenomas occur most commonly in and what age
Females
Younger patients i.e.
Bilateral adrenal hyperplasia occurs more commonly in what sex and what age
Men and at an older age
Who are more like to get an adrenal carcinoma
Females - between 50 and 70 years
What is the function of aldosterone
It stimulates sodium reabsorption and potassium and hydrogen loss by acting on the distal renal tubules
What does excessive aldosterone secretion result in
sodium and water retention
hypertension
hypokalaemia
metabolic acidosis
What condition typically has aldosterone producing adenomas
Conn’s syndrome
Describe the appearance of a aldosterone producing adenoma
Usually 0.5-2cm and have a yellow colour due to their high cholesterol content
What is aldosterone production sensitive to in aldosterone producing adenomas
adrenocorticotrophic hormone (ACTH)
What is bilateral adrenal hyperplasia also known as
idiopathic hyperaldosteronism
Which part of the adrenal gland produces aldosterone
Zona glomerulosa
What is the zone glomerulsa very sensitive to in bilateral adrenal hyperplasia
Angiotensin 2
What is glucocorticoid-suppressible hyperaldosteronism
a rare autosomal dominant condition
What is glucocorticoid-suppressive hyperaldosteronism usually associated with
Bilateral adrenal hyperplasia
What are aldosterone-producing carcinomas associated with
hyper secretion of cortisol, androgens and oestrogen, as well as high levels of aldosterone
How do patients with primary hyperaldosteronism usually present
hypertension and hypokalaemia
What might hypokalaemia cause
fatigue muscle weakness cramps polydipsia polyuria
What is a characteristic presentation of patients with glucocorticoid-suppressible hyperaldosteronism
Early haemorrhagic strokes
What is the initial screening test
what would a positive screen test involve?
a measurement of plasma aldosterone concentration and plasma renin activity
Raised plasma aldosterone concentration to renin ratio
What must be done prior to measuring the aldosterone to renin ratio
stop antihypertensives as they increase plasma renin activity
Hypokalaemia should be corrected (oral potassium chloride supplementation)
In what case might a false negative result of primary hyperaldosteronism be seen
patients with chronic renal failure
What is a normal response following a sodium (salt) load
Aldosterone suppression
What result would confirm primary hyperaldosteronism with a salt (sodium) loading test
Failure of aldosterone suppression
How is a salt loading test carried out
Oral sodium chloride tablets tds. on the 3rd day, a 24 hour urine specimen is collected for measurement of aldosterone, sodium and creatinine
What is the treatment for unilateral adenomas
surgery
What is the treatment for bilateral adrenal hyperplasia
lifelong pharmacotherapy with aldosterone antagonists
In patients with adrenal adenomas, their aldosterone levels are lower at noon. why is this
the circadian secretion of pituitary ACTH releases reaches a nadir during the day
What type of imaging is used for suspected primary hyperaldosteronism
CT or MRI
What test can confirm the difference between a unilateral aldosterone producing adenoma and bilateral hyperplasia
Adrenal vein sampling by an experienced radiologist
Describe the ratio of aldosterone to cortisol in a unilateral aldosterone-producing adenoma
Ratio is 4-5 times greater than that of the opposite side
What is the treatment for bilateral adrenal hyperplasia
Spironolactone (200-400mg/ day) is used to treat hypertension and hypokalaemia
What are some side effects of spironolactone
gynaecomastia impotence menstrual irregularities muscle cramps GI upsets
What is an alternative to spironolactone if there are intolerable side effects
eplerenone
What is the treatment for an aldosterone producing adenoma
Adrenalectomy (laparoscopic is increasingly being used
What drug must be stopped prior to an adrenalectomy and why
Spironolactone - it can cause mineralocorticoid deficiency after this surgery
What is the treatment for adrenal carcinoma
Surgery and postoperative mitotane
What is the prognosis for adrenal carcinoma
poor
What are some other causes of endocrine hypertension
Cushing\s sundrome
Phaeochromocytoma
acromegaly
primary hyperparathyroidism
