Which set of electrolytes is most commonly monitored to detect refeeding syndrome?

• A. Potassium, magnesium, phosphorus
• B. Sodium, chloride, bicarbonate
• C. Calcium, iron, zinc
• D. Phosphate, copper, selenium

Answer: (A)

Refeeding syndrome hinges on rapid shifts of key electrolytes when nutrition is restarted in a severely malnourished patient. Insulin rise after feeding drives potassium, magnesium, and phosphorus into cells, so deficits in these electrolytes develop quickly and drive the dangerous complications of refeeding. Among these, potassium, magnesium, and phosphorus are monitored because they reflect the most sensitive and clinically relevant changes: phosphate often drops first due to its role in ATP production and glycolysis, while potassium and magnesium losses contribute to arrhythmias and neuromuscular weakness. Regularly checking these three during refeeding allows early recognition and targeted supplementation to prevent serious outcomes. The other groupings don’t align as directly with the hallmark electrolyte disturbances seen in refeeding syndrome, since they relate more to acid-base balance or to micronutrient deficiencies not driven by the immediate refeeding physiology.