Refeeding Syndrome Management Issues Stella Hahn Pulmonary/Critical Care Fellow 2013

Case Presentation 35F with anxiety and depression presents with weakness. Patient began to have dysphagia 5 days prior to admission, initially with solids then with liquids. Unable to tolerate anything PO for 3 days prior to admission per report. Fiance had to carry her around as she was too weak to get around

Case Presentation PMH: Anxiety, Depression, Past history of hospitalization for malnutrition PSH: None VS on admission: Afebrile, 73/47, 107, 14, 97% Admission labs:

Refeeding Syndrome In significantly malnourished patients, initial stage of nutritional replenishment causes electrolyte and fluid shifts that may precipitate disabling or fatal complications Hypophosphatemia Hypokalemia Hypomagnesemia Vitamin and trace mineral deficiencies Volume overload Edema

Hypophosphatemia Hallmark of refeeding syndrome Stores of phosphate are depleted during episodes of starvation When nutritional replenishment begins and patients are fed carbohydrates, insulin is released which triggers cellular uptake of phosphate (and potassium and magnesium) Insulin also causes cells to produce molecules that require phosphate (ATP and 2,3-diphosphoglycerate) Lack of phosphorylated intermediates causes tissue hypoxia and resultant myocardial dysfunction and respiratory failure

Vitamin and Trace Minerals Deficiencies are due to starvation Exacerbated by onset of anabolic processes that accompany refeeding

Volume Overload Begins with increase in insulin secretion during the early stages of refeeding This eventually increases renal sodium reabsorption and retention, and then fluid retention

Risk Factors Directly related to amount of weight loss and rapidity of weight restoration – Patients who weigh less than 70 percent of ideal body weight Low serum levels of phosphate, potassium or magnesium prior to refeeding the patient Little or no nutritional intake for 5-10 days Highest risk in the first two weeks or nutritional replenishment and weight gain

Cardiovascular Complications Most fatalities due to cardiac complications Impaired contractility Decreased stroke volume Heart failure Arrhythmias Atrophy of heart during starvation renders patient more vulnerable to fluid overload and heart failure

Cardiovascular Complications Bradycardia expected in anorexia nervosa A normal heart rate may be harbinger of cardiac compromise During early stages of refeeding, a heart rate > 70 may suggest heart failure and refeeding syndrome

Pulmonary Complications Impaired diaphragmatic contractility Dyspnea Respiratory failure and need for mechanical ventilation are rare Heart failure may secondarily lead to respiratory symptoms and failure

Muscular Complications Impaired contractility Weakness Myalgia Tetany Hypophosphatemia may cause rhabomyolysis

Gastrointestinal Complications Mildly elevated AST/ALT, alkaline phosphatase, bilirubin during first few weeks of refeeding due to excessive calories and fat deposition – Usually not clinically signifcant – Resolve by reducing rate of nutritional replenishment – More calories may be reintroduced once liver tests normalize (malnutrition and hepatic apoptosis can also elevate liver enzymes which normalize with nutritional replenishment) Diarrhea, due to atrophy of intestinal mucosa and pancreatic impairment Nausea/vomiting Abdominal pain Constipation due to delayed gastric emptying and prolonged colonic transit time

Neurologic Complications Tremors, paresthesias, delirium, seizures due to electrolyte abnormalities Wernicke’s encephalopathy – Oculomotor dysfunction – Gait ataxia – Encephalopathy – Thiamine (100mg) should be given at least 30 minutes before starting nutritional replenishment

Prevention Restore weight with calories close to and above and resting energy expenditure Electrolyte deficiencies should be corrected prior to initiating refeeding