Prolonged hyperkalemia following unilateral adrenalectomy for primary hyperaldosteronism

Hypokalemia associated with aldosterone-producing adenomas (APA) are almost corrected following successful unilateral adrenalectomy. Prolonged hyperkalemia after unilateral adrenalectomy is rarely reported and may be overlooked. We describe a 62-year-old man who presented with fatigue and dizziness 2 weeks after unilateral adrenalectomy for aldosterone-producing adenomas. Physical examination showed decreased skin turgor and postural hypotension. Laboratory studies revealed hyperkalemia (6.3 mmol/l) with a low transtubular potassium gradient of 5. A relatively low plasma aldosterone concentration and high plasma renin activity in the setting of normal plasma cortisol and adrenocorticotropic hormone levels lead to a diagnosis of functional hypoaldosteronism. Fludrocortisone 0.2 mg/day for one week completely corrected his hyperkalemia which recurred after cessation of fludrocortisone. Long-term suppression of contralateral aldosterone synthesis by APA and/or chronic untreated hypokalemia may have accounted for the development of prolonged hyperkalemia after unilateral adrenalectomy. Serum potassium concentration following unilateral adrenalectomy must be meticulously monitored to avoid life-threatening hyperkalemia.