Primary hormone excess (increased effective circulating volume) primary aldosteronism Cushing 's syndrome SIADH Primary renal sodium retention (increased effective circulating volume) renal failure SIADH: syndrome of inappropriate antidiuretic hormone production◼ Primary hormone excess (increased effective circulating volume) primary aldosteronism Cushing ‘s syndrome SIADH ◼ Primary renal sodium retention (increased effective circulating volume) renal failure SIADH: syndrome of inappropriate antidiuretic hormone production