Anti-diuretic hormone (ADH), is a neurophysial hormone which is synthesised in the supraoptic nuclei of the hypothalamus and released from the posterior pituitary gland. It binds to vasopressin V2 receptor in the basolateral membrane of the collecting duct, which leads to the insertion of aquaporin-2 receptors for retaining water in the body. By retaining water and decreasing urine output it increases the electrolyte free water in vascular compartment causing hyponatremia.Hyponatremia leads to hypotonicity of extracellular fluid (ECF) resulting in movement of water into intracellular space hence cell swells and cerebral edema occurs.Clinical presentation of acute hyponatremia (decrease in Na over ≤48 hours to <135meq/L) includes headache, lethargy and seizures, and potentially even respiratory and cardiac arrest secondary to brain stem herniation.2,3 These outcomes are more likely to be seen with severe acute hyponatremia (Na <130 mmol/L) and because of their higher brain/intracranial volume ratio, children are at increased risk for these sequelae compared with adults.Several studies have consistently showed that postoperative patients have an increased risk of developing hyponatremia.The incidence of hyponatremia after administration of hypotonic solutions varies from 11 to 31%.