Approach to feeding and eating disorders Quiz: Ace Your Exams

A 19-year-old man comes to the primary care office for evaluation of muscle cramping since his annual physical exam three months ago. He also reports generalized weakness. He does not note any relieving factors or provoking factors for either symptom. The patient has no history of medical or psychiatric conditions. He reports that he started a rigorous weight-lifting program about one year ago. The patient is calm with moments of irritability during this visit. Temperature is 36.6°C (97.9°F), pulse is 75/min, respirations are 16/min, blood pressure is 115/75 mmHg, and body mass index (BMI) is 19.0 kg/m². Physical examination shows a thin young adult male, who is awake and alert and in no acute distress. Musculoskeletal exam shows increased muscle tone and more vascularity in his bilateral upper extremities relative to the previous visit three months prior. Cardiopulmonary and abdominal examinations are within normal limits. Serum magnesium is 1.1 mEq/L, and serum phosphorous is 2.5 mg/dl. Which of the following is the most appropriate next step in management?