Unilateral Primary Aldosteronism with Spontaneous Remission after Long-Term Spironolactone Therapy

Context: Medical treatment with a mineralocorticoid receptor (MR) antagonist, which has produced spontaneous remission of bilateral primary aldosteronism (PA), may also produce spontaneous remission of unilateral PA, for which laparoscopic adrenalectomy is recommended. However, few reports exist regarding spontaneous remission after MR antagonist therapy in unilateral PA. Objective: The aim of this paper is to report a case of unilateral PA with spontaneous remission and reduction of cardiac hypertrophy after long-term spironolactone (SP) therapy. Results: A41-yr-old Japanese male was treated for hypertension and hypokalemia for 5 yr. Primary aldosteronism was diagnosed by a furosemide and upright posture test and a captopril challenge test. Computed tomography imaging showed a 5-mm left-sided adrenal mass. Adrenal vein sampling demonstrated overproduction of aldosterone from the left adrenal gland. Long-term treatment with SP normalized the plasma aldosterone concentration. After discontinuation of SP, the patient's blood pressure, serum potassium level, and plasma aldosterone concentration remained in the normal range. The associated cardiac hypertrophy also improved and continued to resolve even after discontinuation of SP. Although the left adrenal gland tumor was still present on computed tomography after treatment, a furosemide and upright posture test, a captopril challenge test, and a saline loading test produced no evidence of PA. Adrenal vein sampling demonstrated no sign of lateralization. Conclusion: These results demonstrate that SP not only antagonizes the MR, but also decreases aldosterone synthetic activity, which may produce remission in some patients with unilateral PA. (J Clin Endocrinol Metab 97: 1109-1113, 2012)