Be Alert for the Development of Refeeding Syndrome
William S. Hoff MD
Phosphate (PO4 2-) is the most abundant intracellular anion, the majority of which is found in bones. As a result, the measured serum PO4 2- does not accurately reflect the total-body content of PO4 2-. Biologically, PO42- is an important component of cell membranes (e.g., phospholipids), enzyme systems, and bone matrix (e.g., hydroxyapatite). Phosphate is also a component of adenosine triphosphate (ATP), an important source of cellular energy. Synthesis of 2,3-diphosphoglycerate (2,3-DPG) also depends on PO42-.
Watch Out For
Hypophosphatemia is the hallmark electrolyte abnormality associated with the refeeding syndrome. Concomitant serum abnormalities include hypokalemia, hypomagnesemia, and hyperglycemia. Refeeding syndrome is rare, occurring in 0.8% of hospitalized adults. However, the mortality in hospitalized patients who develop severe hypophosphatemia (serum PO42- ≪1 mg/dL) is 30%. Risk factors for refeeding syndrome include prolonged malnutrition, gastrointestinal losses (e.g., vomiting, nasogastric suctioning, diarrhea), chronic alcohol abuse, abdominal surgery, and metastatic cancer.