Hypokalemia-Induced Rhabdomyolysis Caused by Adrenal Tumor-Related Primary Aldosteronism: A Report of 2 Cases

BACKGROUND Primary aldosteronism, also known as Conn's syndrome, is a clinical condition caused by excessive production of aldosterone. The classic presenting signs of primary aldosteronism are hypertension and hypokalemia. However, rhabdomyolysis induced by severe hypokalemia is a rare manifestation of primary aldosteronism. There were only a few cases presented in the English literature over the last 4 decades. CASE REPORT We present 2 cases, a 53-year-old man and a 46-year-old man, with severe hypokalemia-induced rhabdomyolysis caused by adrenal tumor-related primary aldosteronism. Both of these patients were under medical treatment with oral anti-hypertension drug for hypertension, but were poorly controlled. They both presented to the Emergency Department with muscle weakness and pain. Laboratory testing showed elevated creatinine phosphokinase (CPK) and low serum potassium levels. Hypokalemia-induced rhabdomyolysis was suspected. A further endocrine survey showed low PRA (plasma renin activity) and high aldosterone levels, finding which are compatible with primary aldosteronism. Computed tomography (CT) was arranged for further evaluation, and adrenal tumors were found in both cases. Both patients underwent robotic-assisted laparoscopic adrenalectomy. In both cases, there was no recurrence of hypokalemia without potassium supplementation, and their hypertension was under better control at further follow-up visits. CONCLUSIONS Hypokalemic rhabdomyolysis is a rare manifestation of primary aldosteronism. It might be difficult to making a diagnosis when rhabdomyolysis and severe hypokalemia are the first manifestations in patients with primary aldosteronism. The use of diuretics for hypertension treatment might be a risk factor for extremely low potassium levels, which can induce rhabdomyolysis in patients with primary aldosteronism.