<prompt> Answer this question truthfullyWhat are the possible causes of euvolemic hyponatremia with UOsm 100 and urine Na 40?  <response>: <reason> What are the possible causes of euvolemic hyponatremia with UOsm 100 and urine Na 40? The most likely causes are SIADH, hypothyroidism, or glucocorticoid deficiency. 