Daily Monitoring Can Reduce Risk of the Refeeding Syndrome

One of the hazards for patients with anorexia nervosa who are hospitalized for refeeding is the “refeeding syndrome,” which involves fluid and electrolyte abnormalities, including low serum phosphorus levels (hypophosphatemia). Severe hypophosphatemia can lead to cardiac dysrhythmias, delirium, and even sudden death.

According to Rollyn M. Ornstein, MD and colleagues at Schneider Children’s Hospital, New Hyde Park, NY, serum phosphorus levels are at their lowest point during the first week of refeeding (J Adoles Health 2003;32:83). Because of this, it’s essential to monitor serum phosphorus levels every day, particularly when the patient is severely malnourished. According to the authors, close monitoring, with supplementation when needed, will help avoid the refeeding syndrome.

Pressure for shorter hospitalization

Because many of the medical complications of AN can be reversed with nutritional rehabilitation, in some managed-care settings there is pressure to increase the rate of refeeding to shorten the length of hospitalization. At the authors’ hospital, the amount of weight that patients contract to gain every 4 days has risen over the last 7 years from 1.2 lb to 1.6 lb, and the group noticed that the instances of refeeding syndrome seemed to be increasing. When they reviewed the charts of 69 patients with anorexia nervosa (66 females and 3 males) consecutively admitted between July 1, 1998 and June 30, 2000, they found that 4 patients (5.8%) had developed moderate hypophosphatemia (<2.5 and ≥1.0 mg/dl) and 15 (21.7%) had developed mild hyphophosphatemia (<3.0 and ≥2.5 mg/dl). The 69 patients were started on 1200 to 1400 kcal/day, and calories were increased by 200 kcal every 24-48 hours.

Those who developed moderate hypophosphatemia were significantly more malnourished than those who did not develop it, and the low points of phosphorus were directly proportional to percentage of ideal body weight. More than 75% of patients reached their lowest serum phosphorus levels within the first week of hospitalization. Overall, 27.5% of patients required phosphorus supplementation.

According to Dr. Ornstein and colleagues, the incidence of hypophosphatemia appears to be related to the rate of refeeding, and seems particularly linked to increased intake of carbohydrate. The abrupt shift to glucose metabolism that occurs during refeeding is accompanied by greater requirements for and utilization of phosphorus-containing intermediates, such as adenosine 5′ triphosphate (ATP). In malnutrition, atrophy of cardiac muscle, as well as electrocardiographic abnormalities, most often sinus bradycardia, occur. The heart thus becomes more vulnerable to the effects of phosphate depletion, leading to ventricular dysrhythmias.

Although some authors advocate phosphorus supplements before and during refeeding, Ornstein and collegues were able to help patients avoid the refeeding syndrome by monitoring phosphorus and aggressively using phosphorus supplements as needed.