Evaluation of various confirmatory tests for the diagnosis of aldosterone-producing adenoma.

INTRODUCTION: Adrenal venous sampling is useful for discriminating unilateral and bilateral hypersecretion in patients with primary aldosteronism, but it is relatively invasive. To determine the site of hypersecretion more non-invasively, we evaluated predictors of unilateral hypersecretion. MATERIALS AND METHODS: We evaluated the baseline characteristics and the results of confirmatory tests of 123 patients with primary aldosteronism who underwent adrenal venous sampling. RESULTS: Unilateral hypersecretion was identified in 22.0%. The plasma aldosterone concentration and aldosterone-renin ratio were significantly higher and serum potassium concentration and plasma renin activity were significantly lower in patients with unilateral hypersecretion. Plasma aldosterone concentrations after captopril challenge test, saline infusion test and rapid adrenocorticotropic hormone stimulation test were significantly higher among patients with unilateral hypersecretion. The plasma aldosterone concentration reduction ratio in saline infusion test and plasma aldosterone concentration elevation ratio during rapid adrenocorticotropic hormone stimulation test were significantly higher in patients with unilateral hypersecretion. However, areas under the curve for these parameters were not superior to the values after confirmatory tests. CONCLUSIONS: The plasma aldosterone concentration values after captopril challenge test, saline infusion test and rapid adrenocorticotropic hormone stimulation test were useful for identifying patients with unilateral hypersecretion. However, value changes or ratios during confirmatory tests are less useful for this aim.

Syndrome of inappropriate secretion of antidiuretic hormone associated with angiotensin-converting enzyme inhibitor therapy in the perioperative period.

INTRODUCTION:: Angiotensin-converting enzyme (ACE) inhibitors are one of the most commonly used medications for hypertension. Rarely, ACE inhibitors have the potential to cause a syndrome of inappropriate secretion of antidiuretic hormone (SIADH). CASE PRESENTATION:: A 70-year-old woman with > 10 years ACE inhibitor therapy with normonatremia suddenly developed severe SIADH when she took a liquid diet in the uneventful perioperative period, with hemodynamic stability and no surgical complications. She promptly recovered from SIADH subsequent to discontinuing the ACE inhibitor therapy and changing her diet. Therefore, it was assumed that excess antidiuretic hormone secretion due to an ACE inhibitor and free water load from the liquid diet contributed to hyponatremia in our patient. CONCLUSION:: Patients treated with an ACE inhibitor can latently experience inappropriate secretion of antidiuretic hormone, and rapidly develop severe hyponatremia together with additional factors affecting water or salt homeostasis regardless of the length of the administration duration. Clinicians should monitor serum sodium levels in such patients not only just after the initiation of ACE inhibitors but also upon the appearance of those factors.