Lecture 7 Flashcards
What is Refeeding Syndrome?
• The potentially fatal shits in fluid and electrolytes that may
occur in malnourished patients receiving artificial feeding
- Hypophosphatemia
hypokalemia
hypomagnesimia
changes in glucose , pro,fa metabolism
thiamin deficiency
Prevalence of Refeeding Syndrome
Unknown but not uncommon
– Spectrum of manifestations of the condition
– Not all clinicians aware of this problem
• Specific populations started on artificial feeding
– Severely malnourished: 50%
– Anorexia nervosa: 28%
– Cancer: 25%
– Geriatrics: 14%
– GI fistulas: 10%
Etiology of Refeeding Syndrome
Response to aggressive feeding after prolonged fasting or
starvation
Metabolic Changes in Starva)on
Malnutri)on / Starva)on
↓ Insulin, ↑ Glucagon
Glycogenolysis
Gluconeogenesis
Protein catabolism
Shift to fat as fuel source
↑ Ketone bodies
↓ BMR ~20-25%, Deple)on of: Intracellular Minerals (K, Mg, P) Vitamins Electrolytes, Serum concentra,ons of K, Mg, P may be normal
Response to Feeding After Prolonged Starvation
Refeed
↑ Insulin, ↓ Glucagon
↑ glycogen, fat, protein
synthesis
↑ BMR
Rapid cellular uptake of K-> ↓ K ↑ glucose phosphoryla?on ↑ ATP synthesis ↑ Oxida?ve phosphorylation-> ↓ P ↓ Mg ↓ thiamine
Na and water reten?on-> Edema
What’s the Big Deal?
Func3ons
Acute Hypophosphatemia
Func3ons • Intracellular mineral • Cell membrane integrity • Required for energy storage in form of ATP • Regulates O2 delivery to =ssues • Important in renal acid-base buffer system
Acute Hypophosphatemia • Respiratory insufficiency • Decreased cardiac output • Rhabdomyolysis(breakdown of muscle- toxic to kidney • Arrhythmias • Altered mental status • Seizures • Hemolysis • Impaired hepa=c func=on
Potassium
Func%ons
• Major intracellular ca.on
• Integral to normal cellular func.on
• Tightly regulated by ATP-ase pumps
Hypokalemia • Cardiac arrhythmias / arrest • Muscular cramps, pain • Neuromuscular dysfunc.on – Weakness, paralysis, confusion, rhabdomyolysis • Respiratory depression • Delirium • Hallucina.ons
Magnesium
Func%ons • Intracellular cation • Cofactor in oxidative phosphorylation and ATP production • Necessary for structural integrity of DNA, RNA and ribosomes Hypomagnesemia • Cardiac arrhythmias / arrest • Neuromuscular dysfuncAon – Weakness, paralysis, confusion, rhabdomyolysis • Hypertension • Neuropsychiatric disturbances
Thiamine
Func%ons • Essen%al coenzyme in carbohydrate metabolism – Any accelera%on in CHO metabolism can precipitate acute deficiency
Thiamine Deficiency • Wernicke’s encephalopathy – Neurological symptoms caused by brain lesions related to B-vitamin deficiency • Ocular abnormalities • Ataxia • Confused state • Hypothermia • Coma • Korsakoff’s syndrome – Memory disturbances
Which Pa(ents Are at Risk?
hunger stricker
anorhexia
alcoholic /. drug
chronic disease
How to Prevent / Treat Refeeding Syndrome
assess patients at risk
check electrolyte , k,p,Mg
administer thiamin supplements
initiate nutrition therapy slowly- rehydrate carefully
monitor electrolyte based on risk
increase feeding to goal over 4-7 days 200/300 kcals/d,
continue to monitor electrolyte
when in doubt go to conservative- 2kcal/kg/d
Refeeding Syndrome: Summary
Potentially fatal condition
– Precipitated by rapid electrolyte and fluid shifts occurring after rapid
initiation of refeeding after period of undernutrition/starvation
– Can occur after initiation of feeding by any route (po, EN, PN)
• Completely preventable
– Risk assessment
– Guidelines for management
