Medical Nutrition Therapy for Refeeding Syndrome

Medical Nutrition Therapy for Refeeding

Syndrome

Rachel Hammerling

Concordia College, Moorhead MN

Objectives• Be able to describe refeeding syndrome (RFS)

• Be able to describe the pathophysiology of starvation

• Identify the main pathophysiologic features of RFS

• Be able to identify signs & symptoms• Identify recommended treatment & standards of care

• Be able to explain ethical issues involved with treatment & care

Discovery of RFS

• Observed & described after WWII• Victims of starvation experienced cardiac and/or neurologic dysfunction– After being reintroduced to food

• Today, rarely see patients who are severely malnourished, as WWII victims were, in the 1st week– Neurologic signs & symptoms develop later

What is RFS?• Potentially fatal shifts in fluids & electrolytes

• May occur in malnourished patients receiving artificial refeeding– Enterally or parenterally

• Complex syndrome– Sodium & fluid imbalance– Changes in glucose, protein, fat metabolism– Thiamine deficiency– Hypokalemia – Hypomagnesaemia

Understanding Starvation• Glucose = main fuel

– Shifts to protein & fat• Insulin ↓ due to ↓ availability of glucose• Catabolism of protein → loss of cellular & muscle mass → atrophy of vital organs & internal organs

• Respiratory & cardiac function ↓ due to muscular wasting & fluid/electrolyte imbalances

• Body is now surviving by slowly consuming itself

How common is RFS?

• True incidence is unknown• Study of 10,197 patients, incidence of hypophosphatemia = 43 %– Malnutrition one of strongest risk factors

• Parenteral patients = 100% incidence of hypophosphatemia

Pathogenesis

• Electrolytes & minerals involved1) Phosphorus2) Potassium3) Magnesium4) Glucose

Main Pathophysiologic Features

• Disturbances of body-fluid distribution

• Abnormal glucose & lipid metabolisms

• Thiamine deficiency• Hypophosphatemia• Hypomagnesemia• Hypokalemia

Disturbances of Body-Fluid Distribution

• Can influence body functions:1) Cardiac

failure2) Dehydration or

fluid overload3) Hypotension4) Pre-renal

failure5) Sudden death

• CHO refeeding – ↓ water & sodium excretion, resulting in weight gain

• Protein & fat refeeding– Result in weight loss & urinary sodium excretion

– Hypernatremia along with azotemia & metabolic acidosis

Abnormal Glucose & Lipid Metabolisms

• Glucose– Suppress gluconeogenesis → reduced AA usage•Less-negative N balance

– Hyperglycemia

• Glucose → fat (Lipogenesis)– Hypertriglyceridemia, fatty liver, & abnormal liver function tests

Thiamine Deficiency

• Can result in Wernicke’s encephalopathy or Korsakov’s syndrome, associated with:– Ocular disturbance– Confusion– Ataxia

• loss of ability to coordinate muscular movement

– Coma– Short-term memory loss– Confabulation

•Confusion of imagination with memory

Hypophosphatemia• Predominant feature of RFS• Impaired cellular-energy pathways

– Adenosine triphosphate– 2,3-diphosphoglycerate

• Impaired skeletal-muscle function– Including weakness & myopathy

• Seizures & perturbed mental state• Impaired blood clotting processes & hemolysis also can occur

Hypomagnesemia

• Most cases not clinically significant

• Severe cases:– Cardiac arrhythmias – Abdominal discomfort– Anorexia– Tremors, seizures, & confusion– Weakness

Hypokalemia

• Features are numerous:– Cardiac arrhythmias– Hypotension– Cardiac arrest– Weakness– Paralysis– Confusion– Respiratory Depression

Signs & Symptoms

• Electrolyte imbalance– Hypokalemia– Hypophosphatemia– Hypomagnesemia

• REMEMBER: Even an overweight or obese patient can be malnourished & a victim for RFS

Identifying Patients at High Risk of Refeeding Problems

• NICE Guidelines(National Institute for Health & Clinical Excellence)

• Either patient has 1 or more:– BMI <16– Unintentional weight loss >15% in past 3-6 mo– Little/no nutritional intake for 10 days– Low levels of potassium, phosphate, or magnesium before feeding

• Or patient has 2 or more:– BMI <18.5– Unintentional weight loss >10% in past 3-6 mo– Little/no nutritional intake for >5 days– History of alcohol misuse or drugs

Patients at high risk:

• Anorexia nervosa• Chronic alcoholism• Oncology patients• Postoperative patients

• Elderly• Uncontrolled diabetes mellitus

• Chronic malnutrition:– Marasmus– Prolonged fasting or low energy diet

– Morbid obesity with weight loss

• Long term antacid users

• Long term diuretic users

Gastrointestinal Fistula patients

• Usually reveals chronic malnutrition– Due to damaged Gl tract & severe abdominal sepsis

• High risk for RFS• Be aware of condition & treat the same – Diarrhea commonly occurs & can be treated by enteral nutrition

Intervention: Objectives

1) Gradually correct starvation– Use less than full levels of calorie & fluid requirements

2) Advance calories & volume– Monitor cardiac & respiratory side effects

3) Correct vitamin & mineral deficiencies – Especially with symptoms

Intervention: Objectives Cont.

4) Nutrition support in patients at risk should be increased slowly– Assuring adequate amounts of vitamins & minerals

5) Organ function, fluid balance, & serum electrolytes– Monitor daily during 1st week & less frequently after

Intervention: Objectives Cont.

6) Monitor for neurological, hematological, & metabolic complications – Of hypokalemia, hypophosphatemia, & hyperglycemia

7) Prevent sudden death

Intervention: Food & Nutrition

• Begin 20 kcal/kg for 1st 3 days• Progress to 25 kcal/kg• Gradually ↑ by 7th day• Protein start slow, ↑ gradually

– To protect & restore lean body mass

• Restrict CHO to 150-200 g/day– To prevent rapid insulin surge

• CHO in PN – Initiate at 2 mg/kg/min – Fat calories should make up the difference

Intervention: Food & Nutrition

• Maintain fluid balance– Adjust when edema exists

• Adjust for sodium & potassium– Depending on lab values until normal

• Supplements– Thiamin– Other vitamins & minerals as needed

Common Drugs Used

• Replacement of phosphorus, potassium, & magnesium

• Insulin– Used to correct hyperglycemia levels

– Monitor blood glucose levels during refeeding

Recommendation for Phosphate

Phosphate Dose

Maintenance requirement 0.3-0.6 mmol/kg/day orally

Mild hypophosphatemia (0.6-0.85 mmol/l)

0.3-0.6 mmol/kg/day orally

Moderate hypophosphatemia (0.3-0.6 mmol/l)

9 mmol infused into peripheral vein over 12 hours

Severe hypophosphatemia (<0.3 mmol/l)

18 mmol infused into peripheral vein over 12 hours

Recommendation for Magnesium

Magnesium Dose

Maintenance requirement 0.2 mmol/kg/day intravenously

(or 0.4 mmol/kg/day orally )

Mild to moderate hypomagnesaemia (0.5-0.7 mmol/l)

Initially 0.5 mmol/kg/day over 24 hours intravenously, then 0.25 mmol/kg/day for 5 days intravenously

Severe hypomagnesaemia (<0.5 mmol/l)

24 mmol over 6 hours intravenously, then as for mild to moderate hypomagnesaemia (above)

Intervention: Nutrition Education, Counseling, &

Care Management• Focus on adequate nutrient intake• Consider referral if food insecurity is a concern

• Offer guidelines according to discharge intervention plan

• Physician may suggest long-term medication use or therapies

NICE Guidelines for Management

Ethical Issues with RFS

• Roles between dietitian, counselor, nurse, doctor, and other professionals

• Working with anorexia patients, oncology patients or older patients

• Ethnic & religious differences– Muslim patients– Non-English speaking patients

Summary Points

• RFS is caused by rapid refeeding after a period of undernutrition

• Characterized by hypophosphatemia• Patients at high risk: undernourished, little or no energy intake for > 10 days

• Start refeeding at low levels• Correction of electrolyte & fluid imbalances before feeding IS NOT necessary

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