Hyperaldoesteronism/ Conn's syndrome

Question 1

in the afferent arteriole in the kidney what are the specialised cells called that sense the BP in the vessel and release renin when detect low BP

Answer 1

juxtaglomerular cells

Question 2

where is angiotensinogen release from

Answer 2

liver

Question 3

tell me about the renin. angiotensin, aldosterone (RAS) pathways

Answer 3

renin converts angiotensinogen into angiotensin I
ACE in lungs converts angiotensin I into II
Angiotensin II stimulates the release of aldosterone from the adrenal glands
this increased BP

Question 4

aldosterone is what kind of steroid

Answer 4

mineralocorticoid

Question 5

how does aldosterone work on the kidney

Answer 5

Increase sodium reabsorption from the distal tubule
Increase potassium secretion from the distal tubule
Increase hydrogen secretion from the collecting ducts

Question 6

What is primary hyperaldoesteronism aka conn’s syndrome and what are the renin levels like

Answer 6

adrenal glands are directly responsible for producing too much aldosterone

renin levels will be low as it is suppressed by the high BP

Question 7

what are the possible causes of Primary Hyperaldoesteronism (Conn’s Syndrome)

Answer 7

An adrenal adenoma secreting aldosterone (most common)
Bilateral adrenal hyperplasia
Familial hyperaldosteronism type 1 and type 2 (rare)
Adrenal carcinoma (rare)

Question 8

what is secondary hyperaldoesteronism and what are the renin levels like

Answer 8

Secondary hyperaldosteronism is where excessive renin stimulating the adrenal glands to produce more aldosterone. Serum renin will be high.

Question 9

what are some of the causes of secondary hyperaldoesteronism

Answer 9

There are several causes of high renin levels and they occur when the blood pressure in the kidneys is disproportionately lower than the blood pressure in the rest of the body:

Renal artery stenosis
Renal artery obstruction
Heart failure

Question 10

renal artery stenosis is usually found in patients with ……….

Answer 10

atherosclerosis as a plaque causes a narrowing of the vessel (similar to how it does with angina)

Question 11

how do you confirm renal artery stenosis

Answer 11

doppler ultrasound, CT angiogram or magnetic resonance angiography (MRA).

Question 12

how do you investigate for hyperaldoesteronism

Answer 12

renin / aldosterone ratio:

High aldosterone and low renin indicates primary hyperaldosteronism
High aldosterone and high renin indicates secondary hyperaldosteronism

Question 13

apart from renin/aldosterone levels what other things can you investigate relating to hte effects of aldosterone

Answer 13

Blood pressure (hypertension)
Serum electrolytes (hypokalaemia)
Blood gas analysis (alkalosis)

Question 14

if high aldosterone level is found when what investigations do you want to do and what cause would you be looking for

Answer 14

CT / MRI to look for an adrenal tumour

Renal doppler ultrasound, CT angiogram or MRA for renal artery stenosis or obstruction

Question 15

what is the management of hyperaldosteronism

Answer 15

Aldosterone antagonists

Eplerenone
Spironolactone
Treat the underlying cause

Surgical removal of adenoma
Percutaneous renal artery angioplasty via the femoral artery to treat in renal artery stenosis

Question 16

what is the most common cause of secondary hypertension

Answer 16

hyperaldoesteronism

Question 17

in what circumstance should you test a person with HTN for hyperaldoesteronism

Answer 17

if they have high blood pressure that is not responding to treatment
(could also have low K+ but this isn’t always the case)