A 27-year-old Caucasian woman (shown) is admitted to the hospital with a body mass index (BMI) of 16. A nasogastric tube is placed, and feeding is initiated.
Of the following laboratory values, which is the most important one to watch at this point?
Answer: A. Phosphorus.
This patient has anorexia nervosa. When an anorexic patient is admitted and enteral feeding initiated, there is a very high risk of refeeding syndrome. Daily levels of phosphorus, calcium, and magnesium must be monitored so as to prevent additional complications. Severe hypophosphatemia can occur within hours of initiating feeding and may be manifested as muscle weakness, paresthesias, seizures, coma, cardiopulmonary decompensation, and even death if appropriate phosphate supplementation is not provided.