ROSH Gastrointestinal Practice Exam

What laboratory finding is most consistent with refeeding syndrome in a patient with anorexia nervosa?

1. Hyperkalemia

2. Hypermagnesemia

3. Hypophosphatemia

4. Thrombocytopenia

The correct answer is: Hypophosphatemia

Refeeding syndrome is characterized by a dangerous shift in electrolytes and fluids that occurs when nutrition is reintroduced to someone who has been malnourished or in a state of starvation. In patients with anorexia nervosa, this phenomenon can be particularly pronounced due to previous deficiencies in essential nutrients and electrolytes. Hypophosphatemia is the most consistent laboratory finding associated with refeeding syndrome. When carbohydrates are reintroduced, insulin secretion increases, leading to the uptake of glucose and electrolytes, including phosphate, into the cells. This can result in significant depletion of phosphate levels in the serum, as the body attempts to utilize the incoming nutrition for energy and metabolic processes. In patients with anorexia nervosa, phosphate levels are often already low due to inadequate dietary intake, and the shift during refeeding can precipitate critical hypophosphatemia, which may lead to various complications, including muscle weakness, respiratory failure, and hemolysis. Therefore, recognizing hypophosphatemia as a key indicator can help clinicians identify patients at risk for refeeding syndrome and implement appropriate monitoring and management strategies. Other available options, such as hyperkalemia, hypermagnesemia, and thrombocytopenia, while they may occur under different circumstances