FRCA Notes

Refeeding syndrome

Refeeding syndrome appeared as an SAQ back in March 2019 (37% pass rate).

It isn't formally mentioned in the core or intermediate curricula, although there are several relevant items in Annex F, such as: 'recognises and manages electrolyte, glucose and acid-base disturbances'.

Resources

  • Refeeding syndrome is a rare but potentially fatal complication of nutritional support
  • It is characterised by a severe hypophosphataemia and other metabolic complications
  • In brief, any patient who is malnourished who is subsequently subjected to an increase in caloric intake
Patient states GI disease states Non-GI disease states
Elderly Previous bariatric surgery Anorexia or bulimiae
Drug/alcohol misuse Short gut syndrome HIV/AIDS
Poverty Inflammatory bowel disease Malignancy
Prolonged fasting (>5-10days) Chronic pancreatitis Chronic infection/inflammation
Unintentional weight loss >10-15% body mass Hyperemesis gravidarum

Stratification

Factor Moderate risk (any one of) High risk (any one of) Severely high risk (both of)
BMI (kg/m2) <18.5 <16 <14
Low nutritional intake (days) >5 >10 >15
Unintentional weight loss (%) >10 >15
Electrolytes prior to feeding ↓K+ | ↓PO42- |↓Mg2+
Other History of alcohol abuse + any moderate risk factor


  • Occurs within 72hrs of starting feed (i.e. exposure to exogenous glucose)
  • There is a rapid shift from lipid to carbohydrate metabolism i.e. a shift from a catabolic/starvation state to an anabolic state
  • It leads to a sudden increase in insulin secretion

  • This causes increased cellular uptake of phosphate, potassium, magnesium and glucose, leading to:
    • Hypophosphataemia
    • Hypokalaemia
    • Hypomagnesaemia

    • Altered glucose metabolism
    • Fluid abnormalities
    • Vitamin (particularly thiamine) deficiency
    • Trace element depletion e.g. copper, selenium and zinc

  • Patients suffer the sequelae of rapid decline in serum levels of these electrolytes

Respiratory

  • Respiratory muscle weakness
  • Prolonged mechanical ventilation

Cardiovascular

  • Heart failure due to overload of an atrophied heart which is deprived of phosphate
  • Dysrhythmia
  • Hypotension and shock

Neuro-psychiatric

  • Wernicke's encephalopathy
  • Seizures
  • Delirium
  • Coma

Renal

  • Acute tubular necrosis

Gastrointestinal

  • LFT derangement due to acute fatty liver
  • Delayed gastric emptying
  • Diarrhoea from intestinal atrophy

Musculoskeletal

Haematological

  • Haemolysis
  • Poor platelet function

Immunological

  • Phagocyte dysfunction
  • Susceptibility to infection

Prevention

  • Identify patients at higher risk
  • Initiate nutritional support very slowly
  • Regularly monitor electrolytes and aggressively replace
  • Supplement vitamins, in particular thiamine and vitamin B compounds

Monitoring

  • Central venous access to facilitate:
    • Frequent sampling of electrolytes
    • Administration of concentrated electrolytes
    • Administration of TPN (save a port on the CVC)

  • Check electrolytes within 12hrs of starting feed
  • Monitor daily for three days, then 3x/week for two weeks

  • Urinary catheter and fluid balance monitoring

Nutritional management

  • Don't need to necessarily wait for electrolytes to be in the normal range prior to feeding
  • Ensure thiamine is replaced
  • Start feeding at lower-than-normal caloric values, based on risk of refeeding syndrome:
    • Moderate - 20kcal/kg/day
    • High - 15kcal/kg/day
    • Severely high - 10kcal/kg/day
  • Aggressively replace electrolytes