hyperaldosteronism

Question 1

definition

Answer 1

overproduction of aldosterone by the adrenal cortex

Question 2

hyperaldosteronism can be

Answer 2

primary or secondary

Question 3

aldosterone is secreted

Answer 3

by the cells of the bona glomerulosa in response to renin via the RAAS system

Question 4

RAAS SYSTEM

Answer 4

draw out the pathway

Question 5

aldosterone stimulates

Answer 5

the Na/K+ pump of the principal cells along the distal convoluted tubule this causes potassium to be pumped from the blood into the cell and down its concentration gradient into the urine, and sodium is pumped from the cell into the blood, water follows sodium via osmosis which increases the blood volume and the blood pressure

Question 6

aldosterone also stimulates

Answer 6

the proton ATPase pump of alpha intercalated cells causing more protons to be excreted into the urine, at the same time an ion exchanged on the basal surface of the cell transports negatively charged bicarbonate ions into the extracellular space which causes a metabolic alkalosis by increasing the pH

Question 7

primary hyperaldosteronism is otherwise known as

Answer 7

CONNS syndrome

Question 8

causes of primary hyperaldosteronis

Answer 8

• bilateral adrenal hyperplasia (most common cause)
• adrenal adenoma which secretes aldosterone
• familial hyperaldosteronism: genetic mutation in which the cells of the zona glomerulosa innaproprately secrete aldosterone in response to ACTH as well as secreting aldosterone in response to renin

Question 9

causes of secondary hyperaldosteronism

Answer 9

most commonly is caused by excess aldosterone produced in response to chronic hypotension which activates the RAAS system
- can occur in congestive heart failure and liver cirrhosis

Question 10

symptoms of hyperaldosteronism

Answer 10

• hypokalaemia and hypernatraemia
• metabolic alkalosis
• hypertension due to the increased blood volume
• muscle weakness, paraesthesia and constipation caused by the hypokalaemia

Question 11

initial diagnostic tests for hyperaldosteronism

Answer 11

measure aldosterone and renin levels

• in primary hyperaldosteronism: aldosterone levels are high and renin levels are low due to negative feedback affect
• in secondary hyperaldosteronism: aldosterone levels are high and renin levels are also high

Question 12

if levels of aldosterone are abnormal diagnostic test (but only for primary hyperaldosteronism)

Answer 12

• express aldosterone and renin levels as a ratio (aldosterone to renin ratio) if ratio is elevated carry out a saline suppression test

Question 13

saline suppression test

Answer 13

failure of plasma aldosterone levels to fall by 50% on administration of 2 litres of normal saline confirms diagnosis of primary hyperaldosteronism

Question 14

after diagnosis of primary hyperaldosteronism is confirmed

Answer 14

abdominal CT to determine the cause, a MET PET scan is gold standard to determine whether or not an adrenal adenoma is functional

Question 15

treatment of primary hyperaldosteronism

Answer 15

• if caused by an adenoma: unilateral laparoscopic adrenalectomy
• all other causes are treated with spironolactone

Question 16

spironolacote is

Answer 16

an aldosterone antagonist which acts as a potassium sparing diuretic