Persistent severe hyperkalemia following surgical treatment of aldosterone-producing adenoma

Primary aldosteronism is one of the most common causes of secondary hypertension. This condition is characterized by autonomous hypersecretion of aldosterone which produces sodium retention and potassium excretion, resulting in high blood pressure and potential hypokalemia. Transient postoperative hyporeninemic hypoaldosteronism with an increased risk of hyperkalemia may occur in some patients. We report the case of a 63-year-old patient with persistent hypokalemia, periodic paralysis, and refractory hypertension who was diagnosed with primary hyperaldosteronism due to elevated aldosterone, undetectable plasmatic renin concentration, and the presence of a left adrenal mass. One month after the surgery, the patient was admitted with signs of severe hyperkalemia (8 mmol/L) and worsened renal function, thus requiring hemodialysis. Fluid resuscitation, loop diuretic, and sodium bicarbonate treatment decreased his potassium. Zona glomerulosa insufficiency was confirmed by hormonal tests which exposed low aldosterone-renin axis. The fludrocortisone treatment was initiated and maintained, with consequent potassium and creatinine stabilization. Old age, long duration of hypertension, impaired renal function, severe hypokalemia before surgery, and large size of the aldosterone-producing adenoma are important risk factors for serious potassium imbalance after removal of the adenoma. We have to consider monitoring the patients after surgery for primary hyperaldosteronism in order to prevent severe hyperkalemia; therefore, postoperative immediate follow-up (arterial pressure, potassium, and renal function) is mandatory.