Endocrine Abstracts

Introduction: Primary hyperaldosteronism classically presents with hypertension and hypokalaemia, though many may be normokalaemic. It is most commonly caused by bilateral adrenal hyperplasia, while 30-40% have a unilateral adenoma or nodule. Aldosterone renin ratio (ARR) is performed, with confirmatory testing if required plus adrenal CT to identify an adrenal lesion. Adrenal venous sampling (AVS) distinguishes between unilateral and bilateral disease. Unilateral adrenalectomy is the preferred treatment, or alternatively medical management with mineralocorticoid receptor antagonists for bilateral disease or where surgery is not suitable, with the aim of preventing adverse cardiovascular outcomes of excess aldosterone. Hyperaldosteronism can rarely be seen in adrenocortical carcinoma (ACC).

Clinical case: A 37 year old gentleman was referred to cardiology in 2004 with hypertension and hypokalaemia (K 2.60 mmol/l). Investigations included ARR (aldosterone 331 ng/l, renin 3.2 mu/l, ratio 103.4 (<25)). CT abdomen was reported as showing normal adrenals. He was managed medically for primary hyperaldosteronism with spironolactone. Over the next 15 years he remained hypertensive, requiring Eplerenone 200 mg and five concurrent antihypertensives, with periodic advice sought from cardiology by primary care. During this time he suffered a stroke and developed chronic kidney disease. He presented to dermatology in 2022 with melanoma. Staging CT revealed a 45 mm indeterminate left adrenal lesion. He was referred to endocrinology and underwent functional testing plus PET scanning. Differentials included primary adrenal disease – functioning or non-functioning, low grade ACC or metastatic melanoma. Repeat ARR was markedly elevated (aldosterone 5500 pmol/l, renin 3.6 mu/l, ratio 1537.8), with mild hypercortisolaemia (144 nmol/l) after overnight dexamethasone suppression. Plasma metanephrines were normal. He underwent laparoscopic adrenalectomy in March 2023 with hydrocortisone cover and post-operative antihypertensive reduction. Despite this, renal function declined post-operatively. Histology revealed a 58 mm adrenal lesion with Modified Weiss score of 2 (>25% clear cells, low mitotic rate, high grade focal nuclear change) and favoured carcinoma over adenoma. Adjuvant mitotane was not indicated. Post-operative ARR normalised to 38.5.

Conclusions: This case demonstrates the classic presentation and biochemical diagnosis of primary hyperaldosteronism, but without obvious adrenal adenoma on imaging. This gentleman was lost to follow up and suffered adverse cardiovascular mortality with persistent hypertension despite multi-agent treatment. At the time of presentation to endocrinology there were several differentials, and while histology report favours ACC over adenoma, the low Weiss score could suggest an adenoma in keeping with primary hyperaldosteronism. AVS at the time of first diagnosis may have offered earlier detection of a unilateral aldosterone-producing adenoma with surgical treatment options.