What is the predominant cause of refeeding syndrome in a patient recovering from anorexia nervosa?

Refeeding syndrome is a serious and potentially fatal condition that can occur when feeding is restarted in individuals who are malnourished or have been in a state of starvation, such as those recovering from anorexia nervosa. The predominant cause of refeeding syndrome is the rapid influx of carbohydrates, which stimulates insulin secretion. This process can lead to shifts in electrolytes, particularly hypophosphatemia, due to the reintroduction of calories.

When a patient's nutritional status improves, insulin levels rise, promoting the uptake of phosphate, potassium, and magnesium into cells for energy production and metabolism. As a result, serum levels of these electrolytes, particularly phosphate, can drop dramatically. Hypophosphatemia can lead to a range of complications, including muscle weakness, respiratory failure, hemolytic anemia, and cardiac dysfunction.

Understanding the mechanisms behind refeeding syndrome is essential for effectively managing individuals recovering from anorexia nervosa, as careful monitoring and gradual refeeding protocols can help mitigate the risk of hypophosphatemia and its associated complications. This is why recognizing hypophosphatemia as the predominant cause is critical in the context of refeeding syndrome.