Biochemistry and Refeeding Syndrome

Question 1

reference range for albumin

Answer 1

35 - 50 g/L

Question 2

reference range for amylase

Answer 2

70 - 300 U/L

Question 3

reference range for bicarbonate

Answer 3

22 - 29 mmol/L

Question 4

reference range for bilirubin (total)

Answer 4

< 21 µmol/L

Question 5

reference range for calcium adjusted

Answer 5

2.2 - 2.6 mmol/L

Question 6

reference range for chloride

Answer 6

95 - 108 mmol?l

Question 7

reference range for cholesterol

Answer 7

< 5mmol/L

Question 8

reference range for CRP

Answer 8

0 - 10 mg/L

Question 9

reference range for creatinine kinase (male)

Answer 9

40 - 320 U/L

Question 10

reference range for creatinine kinase (female)

Answer 10

25 - 200 U/L

Question 11

reference range for Creatinine

Answer 11

40 - 130 µmol/L

Question 12

reference range for glucose (blood)

Answer 12

4 - 5.5 mmol/L

Question 13

reference range for HbA1c

Answer 13

6 - 7 % (42 - 53 mmol/mol Hb)

Question 14

reference range for iron

Answer 14

10 - 40 µmol/L

Question 15

reference range for magnesium

Answer 15

0.7 - 1 mmol/L

Question 16

reference range for PCO2 (arterial blood)

Answer 16

4.6 - 6 kPa

Question 17

reference range for pH (arterial blood)

Answer 17

7.35 - 7.45

Question 18

reference range for phosphate

Answer 18

0.8 - 1.5 mmol/L

Question 19

reference range for PO2 (arterial blood)

Answer 19

10.5 - 13.5 kPa

Question 20

reference range for potassium

Answer 20

3.5 - 5.3 mmol/L

Question 21

reference range for total protein

Answer 21

60 - 80 g/L

Question 22

reference range for sodium

Answer 22

133 - 146 mmol/L

Question 23

reference range for triglyceride

Answer 23

< 2.5 mmol/L

Question 24

reference range for urea

Answer 24

2.5 - 7.8 mmol/L

Question 25

reference range for Thyroid stimulating hormone (TSH)

Answer 25

0.4 - 4 mU/L

Question 26

reference range for free thyroxine (FT4)

Answer 26

9 - 22 pool/L

Question 27

reference range for transferrin percentage saturation (male)

Answer 27

< 55%

Question 28

reference range for transferrin percentage saturation (female)

Answer 28

<50 %

Question 29

reference range for parathyroid hormone (PTH)

Answer 29

1 - 6 pmol/L

Question 30

Name symptoms of low phosphorous? (6)

Answer 30

1. heart failure
2. respiratory failure
3. acute kidney injury
4. nausea
5. coma
6. haemorrhage

Question 31

Name symptoms of low potassium? (5)

Answer 31

1. cardiac arrest
2. respiratory depression
3. impaired renal function
4. ileus (lack of movement in intestines, can = blockage)
5. paralysis

Question 32

Name symptoms of low magnesium? (4)

Answer 32

1. arrhythmia
2. respiratory depression
3. diarrhoea
4. coma

Question 33

Name symptoms of low fluid/glucose (3)

Answer 33

1. heart failure
2. pulmonary oedema
3. metabolic acidosis

Question 34

Name symptoms of thiamine depletion? (4)

Answer 34

1. heart failure
2. pleural effusion
3. encephalopathy
4. lactic acidosis

Question 35

Name the steps and mechanisms (pathogenesis) in refeeding syndrome (7)

Answer 35

1. Starvation/malnutrition
2. Protein, fat, mineral, electrolyte and mineral depletion - salt and water intolerance
3. Refeeding (switch to anabolism)
4. Fluid, salt and nutrients (CHO major energy source) ingested
5. Insulin secretion
6. increase in protein and glycogen synthesis
   - increase in glucose uptake
   - utilisation of thiamine
   - uptake of K+, Mg- and PO4
7. Symptoms of refeeding

Question 36

Name symptoms of thiamine depletion? (4)

Answer 36

1. heart failure
2. pleural effusion
3. encephalopathy
4. lactic acidosis

Question 36

Which electrolytes are affected in refeeding syndrome? (5)

Answer 36

1. phosphorous
2. potassium
3. magnesium
4. fluid/glucose
5. thiamine depletion

Question 37

What are the symptoms of refeeding syndrome? (5)

Answer 37

1. hypokalaemia
2. hypomagneaemia
3. hypophosphataemia
4. thiamine deficiency
5. salt and water retention -oedema

Question 38

Describe how you would identify patients at general risk of refeeding

Answer 38

Any patient who has had very little or no food intake for > 5 days

Question 39

Describe how you would identify patients at high risk of refeeding (5)

Answer 39

1. Any patient is at higher risk of RFS if they have one of more of the following
2. BMI <16 kg/m2
3. Unintentional weight loss > 15% within the last 3-6 months
4. Very little or no nutrition for > 10 days
5. Low concentrations of potassium, magnesium or phosphate prior to feeding

Question 40

Identifying refeeding risk: Or if a patient has 2 or more of the following symptoms (4)

Answer 40

1. BMI < 18.5 kg/m2
2. Unintentional weight loss > 10% within the last 3-6 months
3. Very little or no nutrition for > 5 days
4. A history of alcohol abuse of drugs including insulin, chemotherapy, antacids or diuretics

Question 41

Describe how to identify extremely high risk of refeeding (2)

Answer 41

1. BMI < 14 kg/m2
2. Negligible intake for more than 15 days.

Question 42

Managing refeeding risk: How would you initiate feeding regime in patients with refeeding risk? Describe the steps.

Answer 42

If overweight = use ideal/ adjusted body weight

Initiate feeding at 10-20 kcal/kg OR <50% of estimated TEE

Aim for:
1. 40-50% Kcal from carbohydrate
2. Supplement thiamine 100 - 300 mg/day for 2-10 days
3. Supplement B complex
4. Supplement micronutrients
5. Supplement electrolytes

Question 43

If someone if being managed for refeeding risk with regimen, when monitoring for signs of refeeding syndrome what steps would you take if there was no evidence of refeeding syndrome in response to feeding regimen initiation

Answer 43

Progress to 20 kcal/kg thin 48 hours

If still no evidence of refeeding syndrome= Progress to full requirements

Question 44

If someone if being managed for refeeding risk with regimen, when monitoring for signs of refeeding syndrome what steps would you take if there was evidence of refeeding syndrome in response to feeding regimen initiation

Answer 44

Progress to full requirements in 4 - 7 days

Treat electrolyte imbalances