Critical Care · Year 4 · from Critical Care
Case 1: Refeeding Syndrome in a Malnourished Patient
Clinical Image
Source: Wikimedia Commons - Electrocardiogram - Public Domain
Case Presentation
A 45-year-old woman with chronic alcohol use disorder is admitted to the ICU after being found unresponsive. She weighs 42 kg with BMI of 15.8 kg/m2, appearing severely malnourished with temporal wasting and loss of subcutaneous fat. Her NUTRIC score is 7 (high nutritional risk). After initial stabilization, the nutrition support team initiates enteral feeding via nasogastric tube at 25 mL/hour of a standard polymeric formula. On day 2, she develops confusion, tremor, and new-onset atrial fibrillation. Labs reveal phosphorus of 0.8 mg/dL (critically low), potassium 2.9 mEq/L, and magnesium 1.1 mg/dL. ECG shows prolonged QTc of 520 ms. The team recognizes refeeding syndrome and immediately holds tube feeds, administers IV phosphorus replacement (30 mmol over 6 hours), potassium chloride 40 mEq IV, magnesium sulfate 2 g IV, and thiamine 200 mg IV. After electrolyte correction over 24 hours, feeding is restarted at 10 kcal/kg/day (approximately 420 kcal/day) with close electrolyte monitoring every 6 hours. Feeds are advanced by 5 kcal/kg/day every 2-3 days as tolerated. She recovers without cardiac complications and is eventually advanced to goal nutrition over 10 days.
Key Learning Points
- Refeeding syndrome risk factors include BMI less than 16, weight loss greater than 15% in 3-6 months, minimal intake for greater than 10 days, and history of alcohol abuse or chronic malnutrition
- The mechanism involves insulin release with carbohydrate refeeding causing intracellular shift of phosphorus, potassium, and magnesium, leading to dangerous hypophosphatemia
- Prevention requires identifying at-risk patients, starting feeds at low rates (10-20 kcal/kg/day), supplementing thiamine before carbohydrates, and monitoring electrolytes closely during advancement
- Cardiac arrhythmias from electrolyte disturbances (particularly hypomagnesemia and hypokalemia causing QT prolongation) are the most common cause of death