Refeeding syndrome

Refeeding syndrome can manifest with the following derangements EXCEPT which one?

a) Hypophosphataemia

b) Hyperkalaemia

c) Hypomagnesaemia

d) An increase in the minute volume and respiratory quotient

e) Increased extracellular fluid volume

Answer: b

Explanation

Refeeding syndrome occurs in patients after recommencement of feeding following a period of starvation, and this syndrome is not infrequently seen in the critically ill patient. It may occur up to four days after either enteral or parenteral feed has been recommenced. During a period of starvation the secretion of insulin is decreased due to the reduced intake of carbohydrates and the switch to fat and protein catabolism. This results in intracellular depletion of electrolytes, in particular phosphate. This may be in spite of the maintenance of normal serum phosphate levels. Following the commencement of feeding, carbohydrate metabolism resumes and hence insulin production increases. This stimulates cellular uptake of electrolytes, which can lead to profound hypophosphataemia and hypokalaemia. The hypomagnesaemia is secondary to the  phosphate depletion and is due to increased urinary excretion of magnesium. As phosphate is essential for ATP generation, hypophosphataemia can lead to a wide range of problems including rhabdomyolysis, cardiac and respiratory failure, leucocyte dysfunction, metabolic acidosis and arrhythmias. In addition, recommencement of carbohydrate metabolism will cause a sudden increase in CO2 production and O2 consumption, thus increasing both the respiratory quotient and minute volume. Awareness of the potential to develop refeeding syndrome is essential and themainstays of treatment are aggressive electrolyte replacement and frequent monitoring of electrolyte levels.