1. Joanna Prickett North Bristol NHS Trust
Refeeding Syndrome
Joanna Prickett
North Bristol NHS Trust

2. Definition
Severe fluid and electrolyte shifts and related metabolic complications in malnourished patients undergoing refeeding.

3. Consequences of Starvation
Decreased insulin and increased glucagon secretion. With a switch from glucose towards ketone bodies as a source of energy
Glycogen stores used
BMR decreases
Brain adapts to using ketones
Atrophy of all organs
Reduced Lean Body Mass
Abnormal liver function

4. Consequences of starvation
Deficiency of vitamins and trace elements
Whole body depletion of potassium, magnesium and phosphate
Increased intracellular and whole body sodium and water
Impaired cardiac, intestinal and renal reserve, leading to reduced ability to excrete excess sodium and water
Serum concentrations of electrolytes maintained within normal limits

5. Refeeding
Increased insulin release leads to increased uptake of glucose, phosphate and potassium into cells. Magnesium is used as a co-factor for cellular pump activity
Reactivation of the Na/K membrane pump leads to further movement of K into cells with a simultaneous movement of sodium and fluid out of cells

6. Refeeding
Reduced phosphate is associated with increased urinary magnesium excretion
Stimulation of protein synthesis leads to increased anabolic tissue growth which in turn leads to increased cellular demand for phosphate, potassium, glucose and water

7. Refeeding
Excess glucose can lead to hyperglycaemia and fat abnormalities
Reduced sodium and water excretion
Increased cellular thiamine utilisation due to its role as a co-factor for carbohydrate metabolism

8. Consequences of electrolyte abnormalities

9. Incidence 0.2-5% hospital patients have hypophosphataemia
Incidence is increased in certain groups
Incidence in patients receiving nutrition support has been reported to be 30-40%

10. Patients at Risk of Refeeding
Those who have had very little or no food intake for >5 days especially if already undernourished (BMI <20 kg/m2, unintentional weight loss >5% within the last 3-6 months)

11. Patients at High Risk of Refeeding
Patients with any of the following:
BMI < 16 kg/m2
Unintentional weight loss >15% within the last 3-6 months
Very little or no nutrition for >10 days
Low levels of potassium, magnesium or phosphate prior to feeding

12. Patients at High Risk of Refeeding
Patients with 2 or more of the following:
BMI < 18.5 kg/m2
Unintentional weight loss >10% within the last 3-6 months
Very little or no nutrition for >5 days
A history or alcohol abuse or some drugs including insulin, chemotherapy, antacids or diuretics

13. Feeding patients who are at risk
Introduce feeding at maximum 50% of total energy requirements for the first 2 days before increasing to full requirements if no biochemical abnormalities
Meet full requirements for fluid, electrolytes, vitamins and minerals from day 1 of feeding
Monitor appropriate biochemistry including potassium, phosphate and magnesium (see chapter on monitoring)

14. Feeding patients who are at high risk
Consider starting nutrition at maximum 10 kcal/kg and increase slowly to meet full requirements by 4-7 days.
Any increase in feed should be dependent on trends in biochemistry

15. Feeding patients who are at high risk
Potassium, magnesium and phosphate supplementation from the outset (unless blood levels are already high):
Potassium (likely requirement 2-4 mmol/kg/day)
Magnesium (likely requirement 0.2 mmol/kg/day IV, 0.4 mmol/kg/day oral)
Phosphate (likely requirement mmol/kg/day)

16. Feeding patients who are at high risk
Immediately before and during first 10 days of feeding:
Oral thiamine mg/day
Vitamin B co strong 1-2 tds or full dose IV vitamin B
Multivitamin and trace element supplement
Restore circulatory volume and monitor fluid balance closely
Monitor appropriate biochemistry including, potassium, phosphate and magnesium

17. Feeding patients who are at high risk
In extreme case eg
BMI<14 kg/m2
Very little or no nutrition for > 15 days
Pre-feeding Hypokalaemia, hypophosphataemia or hypomagnesaemia
Consider starting feed at 5kcal/kg
It is not necessary to correct electrolyte levels prior to feeding if this cautious approach is used
a level that will be safe even with pre-existing low plasma electrolytes, yet will encourage intra-cellular up-take of the phosphate and electrolyte supplementation that must be started at the same time (as above).

18. Feeding patients who are at high risk
Beware of very malnourished, dehydrated patients with renal impairment and consequently normal or high potassium and phosphate levels.
It is also easy to overlook significant renal impairment in patients with very low BMI and recent starvation who have very low creatinine and urea production.
These can change in hours to very low levels due to the combined effects of dehydration and refeeding.
They may therefore have only modestly raised plasma creatinine and urea levels

19. References
Brook M.J. & Melnik G The Refeeding Syndrome: An approach to understanding its complications and preventing it occurrence. Pharmacotherapy 15(6):
Crook M.A. et al The importance of the Refeeding Syndrome. Nutrition 17:632-7.
Keys A. et al The Biology of Human Starvation vols 1,2. Minneapolis University of Minnesota Press.
Marinella M.A The Refeeding Syndrome and Hypophosphataemia. Nutrition Reviews 61(9):320-3.
NICE 2006 Nutrition Support in Adults
Solomon S.L. et al 1990 The Refeeding Syndrome: A Review. J. Parent. & Enteral Nutrition 14(1):90-7.
Terelevich A. et al Refeeding Syndrome: Effective and safe treatment with phosphates polyfusor. Aliment. Pharmacol. Ther. 17: