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Refeeding Syndrome. Joanna Prickett North Bristol NHS Trust. Definition. Severe fluid and electrolyte shifts and related metabolic complications in malnourished patients undergoing refeeding. Consequences of Starvation.
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Refeeding Syndrome Joanna Prickett North Bristol NHS Trust
Definition • Severe fluid and electrolyte shifts and related metabolic complications in malnourished patients undergoing refeeding.
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
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
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
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
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
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%
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)
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
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
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)
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
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 0.3-0.6 mmol/kg/day)
Feeding patients who are at high risk • Immediately before and during first 10 days of feeding: • Oral thiamine 200-300mg/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
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
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.
References Brook M.J. & Melnik G 1995. The Refeeding Syndrome: An approach to understanding its complications and preventing it occurrence. Pharmacotherapy 15(6):713-26. Crook M.A. et al 2001. The importance of the Refeeding Syndrome. Nutrition 17:632-7. Keys A. et al 1950. The Biology of Human Starvation vols 1,2. Minneapolis University of Minnesota Press. Marinella M.A. 2003. 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 2003. Refeeding Syndrome: Effective and safe treatment with phosphates polyfusor. Aliment. Pharmacol. Ther. 17:1325-1329.