Most common cause of Euvolemic hyponatremia is

(C) SIADH # Euvolemic Hyponatremia can occur in moderate to severe hypothyroidism, with correction after achieving a euthyroid state.> Severe hyponatremia can also be a consequence of secondary adrenal insufficiency due to pituitary disease; whereas the deficit in circulating aldosterone in primary adrenal insufficiency causes hypovolemic hyponatremia, the predominant glucocorticoid deficiency in secondary adrenal failure is associated with euvolemic hyponatremia.> Glucocorticoids exert a negative feedback on A VP release by the posterior pituitary such that hydrocortisone replacement in these patients will rapidly normalize the A VP response to osmolality, reducing circulating A VP.> Syndrome of Inappropriate Anti Diuresis (SIAD) is the most frequent cause of Euvolemic Hyponatremia.> Generation of hyponatremia in SIAD requires an intake of free water, with persistent intake at serum osmolalities that are lower than the usual threshold for thirst; as one would expect, the osmotic threshold and osmotic response curves for the sensation of thirst are shifted downward in patients with SIAD.