E-Poster Presentation 63rd Endocrine Society of Australia Annual Scientific Meeting 2020

A 67 year-old woman was seen in 2014 for management of incidentally found asymptomatic hypokalaemia with a 10 year history of suboptimal blood pressure control despite four antihypertensive medications, Perindopril, Indapamide, Felodipine and Atenolol.

Primary Aldosteronism (PA) was diagnosed by classic clinical features of hypernatraemia, hypokalaemia, alkalosis and significantly elevated aldosterone/renin ratio of 1,132 (pmol/L)/(mIU/L). Serum metanephrines and urinary free cortisol levels were normal.

A dedicated adrenal CT scan showed one adenoma in the right adrenal gland and two in the left adrenal gland. Successful adrenal venous sampling did not show evidence of lateralization. Medical treatment with Spironolactone was commenced at 25 mg twice daily.

In the subsequent 6 years of treatment, the dose of Spironolactone was gradually up-titrated to 75mg twice daily, which elevated her serum renin from 0.5 mIU/L to 80-100 mIU/L (6-46 mIU/L). However, her blood pressure remained elevated, 140-150/80-85 mmHg despite increasing doses of Lercanidipine (from 10mg daily to 20mg daily) and Atenolol (from 25mg daily to 75mg daily). Along with this was her declining kidney function and borderline hyperkalaemia which ranged 4.8-5.4 mmol/L.

Nephrology review suggested that her renal function decline was likely caused by  renovascular disease; glomerulonephritis screening tests were negative and she had small kidneys on ultrasound.

Bilateral disease comprises about 65% of PA ⁽¹⁾, and highlights the importance of AVS in the workup of PA⁽²⁾. This case also illustrates the challenges of medical treatment of PA⁽³⁾. The goals are to fully block the effect of excessive aldosterone and to maintain optimal blood pressure ^(2,3). However, the tendency to hyperkalaemia precluded the use of angiotensin converting enzyme inhibitor or angiotensin receptor blocker. Moreover, longstanding suboptimal blood pressure control has resulted in chronic kidney damage ⁽⁴⁾.

Questions:

- What is the target for mineralocorticoid receptor antagonist therapy?

- How should her blood pressure be managed now?

- What are the treatment options if a patient can not tolerate the needed dose of spironolactone due to its side effect or hyperkalaemia?