Hyponatremia to 30% of elderly patients in nursing homes and is also present in approximately 30% of depressed patients on selective serotonin reuptake inhibitors. People who have hyponatremia who require hospitalisation have a longer length of stay (with associated increased costs) and also have a higher likelihood of requiring readmission. This is particularly the case in men and in the elderly. Hyponatremia Hyponatremia is a low sodium level in the blood. It is generally defined as a sodium concentration of less than 135 mmol/L (135 mEq/L), with severe hyponatremia being below 120 mEq/L. Symptoms can be absent, mild or severe. Mild
Hypotonic hyponatremia blood volume that is no longer there, that has been lost from the body. As a result, their blood volume is reduced. As mentioned above, lack of adequate blood volume is a potent stimulus for ADH secretion and thence water retention. Some patients with hyponatremia have normal or slightly elevated blood volume. In those patients, the increased ADH activity and subsequent water retention may be due to "physiologic" causes of ADH release such as pain or nausea. Alternatively, they may have the Syndrome of Inappropriate ADH (SIADH). SIADH represents the sustained, non-physiologic release of ADH and most often occurs as