Refeeding syndrome, a critical condition in undernourished patients, is characterized by metabolic and electrolyte imbalances that occur upon reintroducing nutrition after a period of prolonged fasting which can lead to a sharp increase in morbidity and mortality rates following their release and the resumption of a normal diet. The occurrence of refeeding syndrome is well-documented in conditions such as anorexia nervosa. However, its prevalence among critically ill pediatric patients remains unclear. These patients often suffer from undernutrition due to chronic llnesses,various congenital and acquired diseases, malabsorption, or child abuse \[2\] There is an increasing awareness of the unexpectedly high prevalence of undernutrition and refeeding syndrome in this population. Studies indicate that between 13% and 20% of patients admitted to pediatric critical care units are undernourished \[3\] The early initiation of enteral nutrition is often recommended for its overall benefits in critically ill children However, it may inadvertently increase the risk of refeeding syndrome. Extended periods of starvation eventually result in the depletion of stored energy, along with a critical reduction in micronutrients and electrolytes, particularly phosphate, potassium, and magnesium. \[5\] Upon refeeding, there is an immediate transition from a catabolic to an anabolic state, marked by a rapid increase in caloric intake and a subsequent rise in insulin secretion. This increase in insulin enhances glycolysis-the process of breaking down glucose for energy. The resulting spike in insulin levels can lead to hypoglycemia and promote the transfer of electrolytes from the extracellular to the intracellular space. This movement can significantly reduce extracellular concentrations of potassium, phosphate, magnesium, and thiamine, which acts as a coenzyme. Given the pre-existing deficiencies in these electrolytes and micronutrients due to prolonged starvation, their levels can quickly fall as they are consumed during the metabolic response to refeeding. This abrupt change can precipitate severe complications associated with refeeding syndrome, which stem from imbalances and deficiencies in electrolyte and micronutrient levels Conditions that place critically ill children at high risk for refeeding syndrome . Clinical conditions Chronic critical illness (e.g., congenital heart disease) . Advanced neurologic impairment Eating disorders(e.g., anorexia nervosa) . Dysphagia Gastrointestinal dysmotility Malabsorption (e.g., short bowel syndrome, inflammatory bowel disease, chronic pancreatitis, cystic fibrosis) . Malignancy Child abuse Significant vomiting and diarrhea Unintentional . weight loss of 5%-10% of body weight in 1-6 months . Prolonged fasting \>7-10 days . Inadequate nutritional intake for 10 day The clinical presentations of refeeding syndrome, which typically manifest in the initial days of nutritional reintroduction, include disturbances in fluid balance, hypoglycemia, hypophosphatemia, hypomagnesemia, hypokalemia, and thiamine deficiency. This syndrome can lead to a range of symptoms that affect the neurological, cardiac, hematological, and gastrointestinal systems, primarily due to electrolyte imbalances. To manage refeeding syndrome in at-risk patients, a gradual and cautious reintroduction of nutrition is advised. The cornerstone of reintroducing nutrition is to incrementally increase caloric intake over a period of several days. It is crucial to monitor serum electrolytes, particularly phosphorus, potassium, and magnesium, and provide supplementation as necessary. If patients exhibit signs of intolerance to the calories despite these precautions, it is advisable to temporarily reduce or maintain the caloric intake at its current level. Once the patients condition has stabilized, a careful and gradual increase in caloric intake may be continued. Additionally, thiamine supplementation is important due to its essential role in carbohydrate metabolism.