Hyperaldosteronism (conn's) Flashcards
What causes primary hyperaldosteronism in Conn’s syndrome?
Autonomous aldosterone production independent of regulators
What are the main causes of primary hyperaldosteronism?
Adrenal adenoma (30%)
Bilateral adrenal hyperplasia (60%)
What genetic mutation is linked to Conn’s syndrome?
KCNJ5 channel
= leading to increased aldosterone production
What is the pathophysiology of primary hyperaldosteronism?
Excess aldosterone increases sodium retention and potassium excretion, causing hypertension
What are the clinical signs of primary hyperaldosteronism?
Hypertension
Hypokalaemia
Hypernatremia
Alkalosis
How is primary hyperaldosteronism treated?
(1) Adrenal adenoma
= Unilateral laparoscopic adrenalectomy > definite treatment
Spironolactone/ eplerenone may be used before surgery to control BP and potassium levels or for patients who are not surgical candidates > first-line management
(2) Bilateral adrenal hyperplasia
= Mineralocorticoid/ spironolactone or eplerenone
How is primary hyperaldosteronism diagnosed?
FIRST INVESTIGATION
(1) Confirm aldosterone excess
Do this by measuring the aldosterone: renin ratio
(2) If the ratio raised → saline suppression test. Failure of plasma aldosterone to suppress by > 50% with 2 litres of normal saline confirms PA
SECOND INVESTIGATION
Confirm subtype
(1) Adrenal CT to demonstrate adenoma
(2) Adrenal vein sampling to confirm adenoma is true source of aldosterone excess
What is a complication of conn’s?
Nelson syndrome
What is the pathophysiology of secondary hyperaldosteronism?
(1) Reduced renal blood flow causes increased renin
(2) This leads to higher angiotensin II and aldosterone
(3) Resulting in sodium retention, potassium excretion, and hypertension
What causes secondary hyperaldosteronism?
Increased aldosterone production due to non-pituitary, extra-adrenal stimuli like reduced renal blood flow
What is the clinical presentation of secondary hyperaldosteronism?
Hypertension
How is secondary hyperaldosteronism diagnosed?
(1) High aldosterone and high renin levels, with a renin/aldosterone ratio.
(2) Doppler ultrasound, CT angiogram or MRA used to check for renal artery stenosis
How is secondary hyperaldosteronism treated?
Aldosterone antagonists
(eg, spironolactone)
Treat underlying cause
(eg, renal artery angioplasty for stenosis
A 56-year-old male presents to his GP with weakness, cramps, paraesthesia. He also notes he has been increasingly thirsty in the last few months. The GP orders bloods which reveal a low potassium
What is the next best investigation?
Aldosterone: renin ratio
A 45-year-old man presents with fatigue, muscle weakness and episodes of severe headaches. Laboratory tests reveal hypokalaemia and metabolic alkalosis
Which condition is most likely responsible for his symptoms?
Conn’s syndrome
A 50-year-old woman presents with uncontrolled hypertension despite being on multiple antihypertensive medications. She also complains of muscle cramps and frequent urination. Blood tests reveal hypokalaemia.
Which condition could be responsible for her symptoms and laboratory findings?
Hyperaldosteronism
What are the key differences between Bilateral Adrenal Hyperplasia and Conn’s Syndrome
(1) Bilateral Adrenal Hyperplasia
Renin levels
= Low renin, high aldosterone
(2) Conn’s Syndrome
(Adrenal Adenoma)
Renin levels
= Low renin, high aldosterone
Typically low potassium and hypertension
Can see it on imaging on conns, can’t see anything in bilateral adrenal hyperplasia
A 61-year-old man is in the hypertension clinic for poorly controlled high blood pressure. This is despite being on several anti-hypertensive medications. He is known to have renal impairment and has some leg swelling. Endocrine testing finds a normal plasma renin-aldosterone ratio, which goes against primary hyperaldosteronism. The actual levels of renin and aldosterone are both elevated.
What condition is most likely to be responsible?
Renal artery stenosis
What is the most common cause of primary hyperaldosteronism?
Bilateral idiopathic adrenal hyperplasia
A plasma aldosterone/renin ratio is performed which suggests a peripheral cause of the patient’s presentation.
What investigation could further differentiate the likely underlying diagnosis and why?
Adrenal venous sampling (AVS)
= can be used to distinguish between unilateral adenoma and bilateral hyperplasia in primary hyperaldosteronism
A 28-year-old man with no past medical history presents to his GP for a hypertension review. Despite lifestyle modifications and a trial of two different antihypertensive medications following an incidental finding of elevated blood pressure 6 months ago during a work-related medical check-up, his blood pressure remains high at 156/88 mmHg. He does not smoke and has no family history of hypertension. Cardiovascular and abdominal examinations are unremarkable, and he is completely asymptomatic.
What is the most likely cause of this man’s hypertension? and why do you say this?
Primary hyperaldosteronism
= Primary hyperaldosteronism is the most common cause of secondary hypertension
A 28-year-old who is 10 weeks pregnant is noted to be hypertensive on her booking visit. Blood shows a potassium of 2.9 mmol/l. Clinical examination is unremarkable
What does this describe?
Primary hyperaldosteronism
