What is the primary cause of refeeding syndrome in patients with anorexia nervosa?

Refeeding syndrome primarily arises due to the metabolic changes that occur when nutrition is reintroduced to individuals who are malnourished, such as patients with anorexia nervosa. When these patients are refed, there is a significant surge in insulin activity, which is a key player in the metabolism of carbohydrates. This surge leads to a rapid uptake of glucose and electrolytes by the cells, causing a shift of electrolytes like phosphate, potassium, and magnesium from the extracellular space into the cells.

This process results in profound electrolyte imbalances, which can manifest as a series of clinical symptoms, including arrhythmias, muscle weakness, and potentially life-threatening complications. Therefore, the surge in insulin activity during the refeeding process is a critical factor that precipitates refeeding syndrome, making it the primary cause of this condition in patients with anorexia nervosa.

While the other options touch on important aspects of patient management and potential complications during refeeding, they do not directly address the metabolic pathophysiology responsible for refeeding syndrome.