Primary aldosteronism (PA) uncommonly presents during pregnancy. Uncontrolled blood pressure may result in adverse maternal and fetal outcomes. We report a case presenting in pregnancy whose management proved particularly challenging, due to variable compliance with therapy, frequent non-attendance at clinic, a subsequent pregnancy and negative imaging.
A 24 year old woman presented at 26 weeks gestation with severe pre-eclampsia and hypokalaemia (2.1 mmol/l). She received intravenous potassium and underwent emergency caesarian section. Investigation postnatally revealed a significantly raised aldosterone/renin ratio at >12250 (aldosterone 2450 pmol/L, plasma renin activity<0.2 pmol/mL/h). Oral potassium replacement was commenced. Plasma aldosterone remained elevated (1580 pmol/L) following intravenous saline loading, confirming a diagnosis of PA. Spironolactone was commenced. CT and MRI scans showed normal adrenals.
She remained hypokalaemic and hypertensive despite being prescribed spironolactone and potassium supplements. Compliance was poor. Further investigations were planned but she defaulted from follow-up. Twelve months after initial presentation she became pregnant again. Spironolactone was stopped. She struggled with potassium supplements due to vomiting and remained hypokalaemic. She was subsequently treated with amiloride and labetalol during the pregnancy and delivered a healthy baby boy at nearly 34 weeks gestation following elective caesarean section.
Postpartum, poor treatment compliance continued. Glucocorticoid remediable aldosteronism was excluded. Repeat adrenal imaging was normal. Adrenal vein sampling (AVS) indicated right adrenal aldosterone excess. Right adrenalectomy was performed and a small adenoma identified. She remains normotensive and normokalaemic off treatment postoperatively.
There are less than 50 published case reports describing PA in pregnancy. Spironolactone is not recommended; epleronone or amiloride can be considered, along with potassium supplements. There is an increased risk of maternal and fetal morbidity and mortality, including preterm delivery, placental abruption and end-organ damage. Our patients first child had multiple medical issues. This case also highlights the importance of AVS which confirmed unilateral aldosterone production despite normal imaging and enabled cure of her PA.