- Refeeding Syndrome = a group of clinical findings that occur in severely malnourished individuals undergoing nutritional support.
- occurs in the setting of prolonged starvation followed by provision of nutritional supplementation from any route.
- chronic malnutrition leads to protein catabolism with total body phosphate depletion despite normal serum phosphate
- introduction of carbohydrates leads to an anabolic state which unmasks total body phosphate depletion and leads to precipitous drop in serum phosphate
- insulin + glucose = massive uptake of phosphate, K+ and Mg2+ into cells
RISK FACTORS – anyone who may be malnourished:
- eating disorders (especially anorexia nervosa)
- prolonged NBM
- chronic malnutrition
- Oncology patients
- Postoperative patients
- Elderly patients (comorbidities, decreased physiological reserve)
- uncontrolled diabetes mellitus (electrolyte depletion, diuresis)
- chronic malnutrition:
- prolonged fasting or low energy diet
- morbid obesity with profound weight loss
- high stress patient unfed for >7 days
- Long term users of antacids (magnesium and aluminium salts bind phosphate)
- Long term users of diuretics (loss of electrolytes)
- Malabsorptive syndrome (such as inflammatory bowel disease, chronic pancreatitis, cystic fibrosis, short bowel syndrome)
- inflammatory process (infectious and non-infectious)
- CVS: arrhythmia, HT, CHF
- GI: abdo pain, constipation, vomiting, anorexia
- MUSC: weakness, myalgia, rhabdomyolysis, osteomalacia
- RESP: SOB, ventilator dependence, respiratory muscle weakness -> requiring intubation and ventilation
- NEURO: weakness, paraesthesia, ataxia, delirium, coma, central pontine myelinosis, seizures, Korsakoff syndrome or Wernicke encephalopathy (confusion, ataxia, ophthalmoplegia)
- METABOLIC: infections, thrombocytopaenia, haemolysis, anaemia
- HAEM: reduced 2,3 DPG production -> left shift of oxyHb dissociation curve
- OTHER: ATN, Wernicke encephalopathy, liver failure
- thiamine deficiency (erythrocyte transketolase or thiamine level)
- trace elements deficiencies
Summary of Management
(1) recognize patients at risk
(2) provide adequate electrolytes, vitamin (thiamine, water and fat soluble) and micronutrient (Zn, Fe, Se) supplementation
(3) careful fluid resuscitation to avoid fluid overload
(4) cautious and gradual energy restoration
(5) monitoring of critical laboratory indices
- A – may need intubation for encephalopathy and bulbar dysfunction with aspiration
- B – ventilation because of respiratory muscle weakness with hypercapnic respiratory failure
- C – correction of electrolytes c/o arrhythmias, cautious slow volume resuscitation, central access and invasive monitoring if haemodynamically unstable
- D – may have profound weakness, cerebellar dysfunction, delirium and coma -> responds to slow correction of electrolytes
Electrolyte abnormalities + Acid Base Disturbance
- Hypokalaemia (<3.5mmol/L) – replace IV or PO
- Hypomagnesaemia (<0.7mmol/L) – replace IV or PO
- Hyponatraemia – don’t correct rapidly unless symptomatic (less than 10mmol/L/day)
- Hyperglycaemia – monitor -> insulin if required
Supportive care and monitoring
- screen those at risk
- Vitamin B6 (pyridoxine) – 1.7mg/day
- Vitamin B12 (cobalamin) – IM injection
- Folate – 400mcg/day
- Fat soluble vitamins – DEKA – can be replaced via feed
- Selenium – 100-400mcg/day LD -> 20-70mcg/day
- Zinc – 10-30mg/day LD -> 2.5-5mg/day
- Iron – no loading dose required -> 10mg/day PO
- managed in an HDU/ICU environment if severe
References and Links
- Khan LU, Ahmed J, Khan S, Macfie J. Refeeding syndrome: a literature review. Gastroenterol Res Pract. 2011;2011. PMC2945646.
- Mehanna HM, Moledina J, Travis J. Refeeding syndrome: what it is, and how to prevent and treat it. BMJ. 2008 Jun 28;336(7659):1495-8. PMC2440847.
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health, a Clinical Adjunct Associate Professor at Monash University, and the Chair of the Australian and New Zealand Intensive Care Society (ANZICS) Education Committee. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of LITFL.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of two amazing children.
On Twitter, he is @precordialthump.