Recognizing, managing medical consequences of eating disorders in primary care

REFEEDING SYNDROME

When refeeding is started, a high glucose load stimulates insulin secretion, resulting in cellular uptake of phosphorus along with potassium, magnesium, and glucose. In addition, total body phosphorus is depleted by the increased demand for adenosine triphosphate and 2,3-diphosphoglycerate for cellular metabolism.

When liver enzyme levels increase, the astute clinician will closely monitor the patient for evidence of refeeding syndrome. In a child, adolescent, or young adult, the standard of care is inpatient monitoring for acute stabilization.^4,19

Hypophosphatemia is the hallmark of refeeding syndrome, although hypomagnesemia, hypokalemia, and hypoglycemia can also occur.⁵³ In addition, sodium and water retention can lead to fluid overload, with shifting of fluid into the intracellular space, resulting in dependent edema.

Cardiovascular complications are the most worrisome manifestations of refeeding syndrome. Electrolyte shifts and increased fluid volume can cause arrhythmias and heart failure. Furthermore, severely undernourished patients may have reduced myocardial mass as well as electrocardiographic abnormalities associated with starvation, which further increase their vulnerability to electrolyte shifts and fluid retention during refeeding.¹⁵

Other manifestations of refeeding syndrome include delirium, seizures, rhabdomyolysis, and respiratory failure. In the most extreme cases, refeeding syndrome causes sudden death.⁵³

Fortunately, refeeding syndrome is easily preventable and treatable when recognized early. Electrolytes and cardiovascular and renal function must be carefully monitored, especially during the first week of nutritional restoration.⁵³ In patients with extremely low body mass (< 70% of ideal body weight) or with precipitous weight loss, close monitoring of the complete metabolic panel including electrolytes, AST, ALT, calcium, magnesium, and phosphorus may be required to detect changes that can affect cardiac status. Specific suggestions for refeeding are discussed below and in Table 2.⁴⁵

ACUTE CARE OF PATIENTS WITH EATING DISORDERS

Refeeding in the inpatient setting

The decision to hospitalize an eating-disorder patient is based on the current or potential risk of serious medical complications and the likelihood of success at home. Medical criteria for hospital admission are outlined in Table 3.^4,54

In refeeding undernourished patients, the challenge is to maximize weight gain while preventing refeeding syndrome. Undernourished patients are generally hypometabolic at baseline but become hypermetabolic once refeeding begins.

How many calories should refeeding start with? The traditional principle of “start low and go slow” has been recently challenged.⁵⁵ Starting at 1,200 kcal/day or less in the typical patient can result in failure to gain weight or even in weight loss in the first week of refeeding.⁵⁶ The goal is to achieve a weight gain of 0.2 kg/day while the patient is in the hospital. Thus, we start higher, and to date we have seen no cases of life-threatening refeeding syndrome. In all patients who need hospitalization or who are beginning the refeeding process as outpatients, caloric intake should be started at 1,500 to 2,000 kcal/day.^45,57 However, for exceptionally low-weight patients, intake may be started lower.

In Australia, patients are started at 1,900 kcal/day.⁵⁶ All patients in one program there receive nasogastric feeding initially in an intensive care unit and then are moved to a regular nursing floor where they graduate to full oral feeding as they improve cardiovascularly and behaviorally. In the United States, some programs use nasogastric feeding at night for caloric restoration; our program and others use nasogastric feeding as a behavioral modification strategy for patients who refuse food or supplements by mouth.

Phosphorus supplementation. Many centers give phosphorus supplements preventively. In our center, we give potassium phosphate (Neutra-Phos) 500 mg orally twice daily for 5 days, and we have seen no life-threatening cases of refeeding syndrome with that regimen. Other centers give phosphorus supplements in a dose of 250 mg orally twice a day for 5 days, while still others only supplement phosphorus reactively once a deficit has been identified. The latter method requires daily blood draws for monitoring and is reactive rather than proactive. Further studies can help clarify the optimal dosing and timing of phosphorus supplementation.

Managing fluid balance. Fluid-loading these patients may tip them over the edge into refeeding syndrome. Except in cases of shock, patients with eating disorders should not be given intravenous fluids, as it is safer to rehydrate and feed them orally. Electrolyte imbalances can be corrected orally with no need for intravenous supplementation. To avoid fluid overload, fluids can be started at 1,500 mL to 2,000 mL per day, with strict monitoring of intake and output. Fluids are liberalized if ALT and AST levels remain normal and to gradually correct orthostatic hypotension; caloric fluids are ideal to help address energy needs and improve bradycardia.

Laboratory monitoring. On admission, a urinalysis, complete blood cell count, complete metabolic panel, TSH, erythrocyte sedimentation rate, serum magnesium, and phosphorus should be obtained.²⁶ In addition, continuous electrocardiographic recording should begin on admission.⁴⁵ Inpatient use of a telemetry bed helps identify extreme tachycardia with arrhythmia, as well as profound bradycardia.^45,56

Some protocols call for daily laboratory monitoring, although that degree of testing is less cost-effective. If initial results are normal, clinical judgment can be used on when to repeat laboratory evaluation. For instance, patients with edema require repeat complete metabolic panels to assess for elevated ALT and AST, electrolyte imbalances, and other abnormalities.

Signs of refeeding syndrome include tachycardia, hepatosplenomegaly, peripheral edema, altered mental status, and electrolyte disturbances, specifically, acute or severe hypophosphatemia or hypokalemia.^26,45 If refeeding syndrome is suspected, the rate of caloric intake should be reduced or not advanced, fluid intake should be urgently reassessed for volume overload, and supportive care with close monitoring should be provided.

KNOWLEDGE SAVES LIVES

Eating disorders can lead to potentially life-threatening medical complications that require attentive care by the primary care clinician and subspecialist. Without thoughtful consideration, it is easy for even a caring medical team to unintentionally enable patients with these illnesses or to cause active harm in the case of underrecognized pathology.⁵⁸

Acute medical stabilization on an inpatient unit trained to recognize pathology and treat sequelae can be lifesaving. Arming patients and families with medical knowledge, as provided in the Academy for Eating Disorders’ brochure, “Critical Points for Early Recognition and Medical Risk Management in the Care of Individuals with Eating Disorders”⁵⁹ can help save patients’ lives.