Video - Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by excessive release of antidiuretic hormone from the posterior pituitary gland or another source. The increase in fluid retention often results in dilutional hyponatremia in which the plasma sodium levels are lowered. SIADH may present with euvolemic hyponatremia with continued urinary sodium excretion. Urine osmolality is usually higher than serum osmolality. Very low serum sodium levels can lead to cerebral edema or seizures. Other symptoms of SIADH include fatigue, confusion, muscle weakness, nausea, vomiting, lack of appetite, and weight loss. Treatment usually involves fluid restriction, salt tablets, IV hypertonic saline, diuretics, and drugs like conivaptan, tolvaptan, or demeclocycline.