THE ADRENAL PARADOX

DECODING A CASE OF PRIMARY HYPERALDOSTERONISM WITH DISCORDANT DIAGNOSTIC CLUES

Abstract

INTRODUCTION/BACKGROUND
Primary hyperaldosteronism (PHA) is a frequently overlooked cause of secondary hypertension, particularly in younger adults. If untreated, it can lead to serious cardiovascular complications. Diagnosis may be challenging when investigations produce conflicting results. We present a case of resistant hypertension due to PHA, successfully treated surgically despite discordant imaging and sampling findings.

CASE
A 45-year-old male with a history of type 2 diabetes, dyslipidaemia and obstructive sleep apnoea was referred for evaluation of hypertension, first diagnosed at age 31. He had persistent hypokalaemia (2.2–2.6 mmol/L) and proteinuria (urine protein-creatinine ratio: 112.9 mg/dL). Initial work-up, including hormonal, cardiac, and renal assessments, showed no significant abnormalities.

However, a positive aldosterone-renin ratio (ARR) of 36, with elevated aldosterone levels (1076 pmol/L) and direct renin (29.5 mU/L), along with a positive saline suppression test (post-infusion aldosterone 910 pmol/L), all confirmed the diagnosis of PHA.

CT imaging showed a small (0.6 × 0.7 cm) nodule in the left adrenal gland and a normal right gland. However, adrenal venous sampling (AVS) revealed lateralisation to the right adrenal gland, indicating it as the source of aldosterone excess. Given the patient's resistant hypertension, large pill burden (including five antihypertensives and high-dose potassium supplements), surgical management was preferred. Following a multi-disciplinary discussion, a right adrenalectomy was performed. Post-operatively, the patient showed significant clinical improvement, reducing his antihypertensive regimen from five to three medications, and potassium supplementation was no longer needed.

CONCLUSION
This case highlights the critical role of accurate ARR sampling and strict adherence to the diagnostic pathway in evaluating PHA. Relying solely on CT imaging can be misleading, particularly with small adrenal lesions, making AVS essential for precise localisation. A systematic, stepwise approach is key to achieving optimal treatment outcomes.