Endocrine Abstracts

Introduction: Primary hyperaldosteronism is a known cause of arterial hypertension, classically with hypokalaemia. About 30–40% of the cases are caused by unilateral aldosterone-producing adenoma, and the recommended treatment is adrenalectomy. Hypoaldestoronism is an uncommon complication of unilateral adrenalectomy, but it can be life-threatening. We present a case of severe hypoaldosteronism after unilateral adrenalectomy for the treatment of primary aldosteronism.

Case presentation: A 66 years old male with long term hypertension on triple drug therapy, chronic kidney disease and persistent hypokalaemia was diagnosed with primary hyperaldesteronism. He had increased aldosterone – 3426 pg/ml (normal 34.7–275 pg/ml) and low renin – 4 uUI/l (normal 4.4–46.1 uUI/l). An elevated plasma aldosterone to renin ratio was compatible with diagnosis. A CT scan revealed a right adrenal nodule suggestive of adenoma (21×19 mm). He was submitted to laparoscopic unilateral adrenalectomy. Pathology confirmed an adrenal adenoma. At discharge, all anti-hypertensive drugs were suspended.

3 weeks after surgery he complained of asthenia, anorexia and diarrhea. Blood tests showed severe hyperkalaemia (7.8 meq/l), metabolic acidosis and acute renal failure (creatinine 4.2 mg/dl). The serum aldosterone was low (43 ng/dl) and renin (4.7 pg/ml) normal. We assume the diagnosis of hyporeninemic hypoaldosteronism and he was treated with fludrocortisone (0.1 mg id), sodium bicarbonate and fluids, with improvement in serum creatinine and normalization of potassium levels. 3 months after discharge he remained asymptomatic but fludrocortisone dependent, with stable potassium and creatinine levels and mild hypertension.

Conclusion: Despite uncommon, hypoaldosteronism after unilateral adrenalectomy is known to occur. Usually mild and transitory, it can also be severe, persistent and life-threatening. Long term hypertension and impaired renal function, both present in our patient, are associated with persistent disease. A close and regular follow-up is essential for earlier detection, especially in high risk patients.