Criteria for Evaluation of Refeeding Syndrome
Refeeding syndrome should be diagnosed based on the presence of electrolyte disturbances (primarily hypophosphatemia, hypokalemia, and hypomagnesemia) and clinical symptoms that emerge after the commencement of nutritional support in malnourished patients. 1
Risk Assessment Criteria
High-Risk Factors (any one of the following):
- BMI <16 kg/m²
- Unintentional weight loss >15% in 3-6 months
- Little or no nutritional intake for >10 days
- Low baseline levels of potassium, phosphate, or magnesium before feeding
Moderate Risk Factors (two or more of the following):
- BMI <18.5 kg/m²
- Unintentional weight loss >10% in 3-6 months
- Little or no nutritional intake for >5 days
- History of alcohol misuse or chronic drug use (insulin, antacids, diuretics) 1
Diagnostic Criteria
Biochemical Parameters:
- Hypophosphatemia - The classic and most frequent electrolyte disturbance
- Hypokalemia - Requirement approximately 2-4 mmol/kg/day
- Hypomagnesemia - Requirement approximately 0.2 mmol/kg/day IV or 0.4 mmol/kg/day orally
- Hypocalcemia
- Fluid imbalance
- Disturbed glucose homeostasis
- Hyperlactatemia (suggesting vitamin B1 deficiency) 1
Clinical Manifestations:
- Fluid retention with peripheral edema
- Congestive heart failure
- Cardiac arrhythmias
- Respiratory failure
- Delirium or encephalopathy
- Other severe organ dysfunctions 1
Timing of Occurrence
Refeeding syndrome typically occurs within the first four days after nutrition therapy is commenced, with the highest risk during the initial 72 hours 1.
Monitoring Protocol
Before Starting Nutritional Support:
- Assess baseline electrolytes (phosphate, potassium, magnesium, calcium)
- Evaluate fluid status and cardiac function
- Check glucose levels
During Nutritional Support:
- Monitor electrolytes daily for the first 3 days, then as clinically indicated
- Pay special attention to phosphate, magnesium, potassium, and thiamine levels 1
- Monitor fluid balance, heart rate, and rhythm
- Assess for clinical signs of fluid overload or electrolyte disturbances
Prevention and Management
Nutritional Approach:
- For high-risk patients: Start at 5-10 kcal/kg/day and increase slowly over 4-7 days 1
- For moderate-risk patients: Start at no more than half of calculated energy requirements during first 2 days 1
- Increase feeding gradually to reach full requirements by day 5-7
- Avoid rapid increases in carbohydrate intake which stimulates insulin release and drives electrolytes intracellularly
Supplementation:
- Thiamine: 200-300 mg daily before and during nutritional repletion
- Balanced multivitamin mixture
- Proactive electrolyte replacement:
- Phosphate: 0.3-0.6 mmol/kg/day
- Potassium: 2-4 mmol/kg/day
- Magnesium: 0.2 mmol/kg/day IV or 0.4 mmol/kg/day orally 1
Special Considerations
Geriatric Patients:
- Older patients have a high overlap between malnutrition risk and refeeding syndrome risk
- Even mild electrolyte deficiencies should be supplemented in malnourished older persons 1
Cancer Patients:
- Cancer patients have increased risk of refeeding syndrome
- Degree of nutritional depletion is the most reliable predictor of risk 1
Common Pitfalls to Avoid
- Failure to identify at-risk patients - Screening should be performed within 24-48 hours of hospital admission
- Inadequate monitoring - Not checking electrolytes before and during feeding
- Overly aggressive refeeding - Starting at too high caloric intake in high-risk patients
- Delayed electrolyte replacement - Waiting for severe deficiencies before supplementing
- Overlooking thiamine supplementation - Critical to prevent Wernicke's encephalopathy
- Focusing only on hypophosphatemia - Refeeding syndrome involves multiple electrolyte disturbances 1
Remember that refeeding syndrome is potentially fatal but entirely preventable with proper risk assessment, cautious nutritional support, and vigilant monitoring of electrolytes and clinical status.