The PMHNP on an inpatient substance disorder unit is reviewing the labs for a 17-year-old patient diagnosed with anorexia nervosa who was recently introduced to a caloric intake program. She has pain on eating, and her labs are as follows: phosphorus 0.7 mg/dL, potassium 1.4 mEq/L, and magnesium 1.8 mg/dL. Which of the following is this patient most at risk for?

Choice A reason: Refeeding syndrome occurs when malnourished patients are introduced to nutritional support, leading to rapid shifts in electrolytes, particularly phosphorus, potassium, and magnesium. The patient’s severe hypophosphatemia, hypokalemia, and low magnesium indicate a high risk for life-threatening complications, including cardiac arrhythmias, respiratory failure, and neurologic dysfunction. Choice B reason: Metabolic alkalosis is characterized by elevated bicarbonate and pH, often caused by vomiting or diuretic use, not the electrolyte shifts seen here. Choice C reason: Hypoglycemia can occur in malnourished patients but is not directly linked to the severe electrolyte disturbances seen with refeeding syndrome. Choice D reason: Purging behaviors refer to self-induced vomiting or laxative abuse, which are behavioral issues, not immediate physiologic risks from nutritional repletion.