Refeeding Syndrome

     
       

 

         
       

Refeeding syndrome occurs when previously malnourished patients are fed with high carbohydrate loads, the result is a rapid fall in phosphate, magnesium and potassium, along with an increasing ECF volume, leading to a variety of complications.

Patients who are malnourished develop a total body depletion of phosphorous; serum phosphorous levels are maintained by redistribution from the intracellular space. The body uses endogenous fuel stores as itís main source of energy. Fat and protein (from muscle) are metabolized.

The delivery of glucose, either enterally or parenterally, as part of a feeding strategy, can cause a huge increase in the circulating insulin level. The patient struggles to cope with converting to exogenous fuel sources. There is rapid uptake of glucose, potassium, phosphate and magnesium into cells. The serum concentration of these agents falls dramatically. In addition, for an unexplained reason, the body swiftly begins to retain fluid, and the extracellular space expands.

The dramatic reduction in serum electrolytes and fluid retention leads to a number of systemic pathologies. There is an increase in cardiac workload, with increased stroke work, heart rate and oxygen consumption. This sudden increase in demand for nutrients and oxygen may outstrip supply. Moreover, in patients with cardiovascular disease, the sudden increase in cardiac work and circulating fluid can precipitate acute heart failure.

The sudden administration of carbohydrates exerts a considerable strain on the respiratory system, whose musculature may well be atrophied due to starvation. There is an increase in CO2 production and O2 consumption, and a resultant increase in the respiratory quotient (RQ). The consequence of this is an increase in minute ventilation, which may cause dyspnea and tachypnea, and make weaning difficult.

The gut atrophies with starvation and the production of digestive enzymes diminishes. With return of enteral nutrition, the gut may be initically intolerant, requiring time to adapt, and many patients complain of nausea and diarrhea.

The serum phosphorous level falls precipitously with refeeding, due to a shift of phosphate from the extracellular to the intracellular compartment, due to the huge demands for this ion for synthesis of phosphorylated compounds. The result of this sudden massive reduction in phorphorous levels is a multitude of life threatening complications involving multiple organs: respiratory failure, cardiac failure, cardiac arrhythmias, rhabdomyolysis, seizures, coma, red cell and leucocyte dysfunction.

The most effective way to treat refeeding is to be aware of it. One should start feeds slowly and aggressively supplement magnesium, phosphate and potassium.

         
                   
       

         
     

       
       

Please note: these tutorials are for personal study purposes only.  They are not currently peer reviewed, and no responsibility will be taken for mistakes or inaccuracies. Reproduction of information is forbidden. All material is copyrighted by the GasWorks Group.