Hyponatremia is one of the complication of inpatient care which is quite common in the pediatric population. This condition often occurs due to the administration of intravenous fluids that are hypotonic and is exacerbated by the condition of SIADH (Syndrome of Inappropriate Anti Diuretic Hormone) which occurs in patients with pain, anxiety, stress, administration of anesthetic agents, narcotics, operative procedures and administration of positive pressure ventilation and infections, especially pneumonia and meningitis. In addition, this condition is also exacerbated by the addition of glucose into the administration of pediatric maintenance fluids. when glucose is metabolized it will leave free water which will affect plasma osmolality. In 2018, the AAP released strong recommendations in administering isotonic fluids as maintenance fluids in pediatric patients in addition to the addition of glucose and potassium. but in clinical practice in hospitals, the use of hypotonic fluids that have been used for a long time is still difficult to abandon because practitioners feel they have not found enough cases of complications. This case report describes a meningoencephalitis patient with status epilepticus who experienced hyponatremia after being given hypotonic fluids according to local guidelines and improved after sodium correction