Biochemistry of Alcohol Abuse

Question 1

What is the classic triad of refeeding syndrome?

Answer 1

Low magnesium, low phosphate and low potassium
Booze, malnutrition and disease

Question 2

Who is at risk of refeeding syndrome?

Answer 2

1 or more of - BMI less than 16kg/m, unintentional weight loss greater than 15%, no nutritional intake for more than 10 days and low Mg, K and phosphate
2 or more - BMI <18.5kg/m, unintentional weight loss more than 10kg, no nutritional intake for more than 5 days and history of alcohol and drugs

Question 3

What will relocate or deplete electrolytes in refeeding syndrome?

Answer 3

Alcohol abuse
Drugs like insulin, antacids and diuretics

Question 4

What is the timeline of refeeding syndrome?

Answer 4

Normal eating - starvation - reintroduction of calories
Anabolism - catabolism - anabolism

Question 5

Describe cellular uptake in refeeding syndrome

Answer 5

Potassium, phosphate and magnesium decrease in malnutrition
ECF is apparently normal (low or normal) mg and PO4 in serum
ICF Mg and PO4 used up during starvation

Question 6

What are the physical signs of low magnesium uptake?

Answer 6

Confusion, delirium, tremors, seizures, tachyarrhythmias, tetany, Chvostek sign, Trousseau sign and ECG changes

Question 7

What are the ECG changes in low magnesium uptake?

Answer 7

Widening QRS complexes
Peaking T waves
Prolonged PR interval

Question 8

What are associated biochemical abnormalities in low magnesium uptake?

Answer 8

Hypokalaemia
Hypocalcaemia
Low parathyroid levels
Low vitamin D levels

Question 9

Describe how insulin drives cellular uptake of potassium

Answer 9

Insulin is used to treat hyperkalaemia to drive potassium into cells
Minima urinary conc. of potassium is 2.5mmol/l - even if whole body is deplete
Move potassium out of cells into blood which can mask the worsening potassium depletion

Question 10

What are the physical exam findings of hypokalaemia?

Answer 10

Weakness and decreased muscle tone

Question 11

What are some complications of prolonged hypokalaemia?

Answer 11

Polyuria due to nephrotic DI and rhabdomyolysis

Question 12

What are the ECG findings of hypokalaemia?

Answer 12

Ventricular tachycardia, atrial tachycardias, PR interval prolongation, P wave amplitude increased, P waves width increased, u waves, T wave inversion and ectopic

Question 13

What happens when glucose is reintroduced in hypophosphatemia?

Answer 13

Massive reuptake in phosphate for ATP production

Question 14

What are the neurological implications of hypophosphatemia?

Answer 14

Seizures, coma, delirium and osmotic demyelination

Question 15

What are the cardiac and MSK implications of hypophospatemia?

Answer 15

Impaired cardiac contractibility and cardiomyopathy
Weakness, ileus and proximal myopathy

Question 16

What are the haematological implications of hypophosphatemia?

Answer 16

Increased propensity for haemolysis

Question 17

What is the treatment of refeeding syndrome?

Answer 17

Reintroduce calories slowly
Expect electrolyte redistribution - phosphate often drops the fastest
Replace electrolytes IV
Give thiamine (Vitamin B1)

Question 18

When does alcoholic ketoacidosis occur?

Answer 18

Tends to occur after a day of massive binge drinking

Question 19

Describe alcoholic ketoacidosis

Answer 19

Can look like DKA with normal glucose
Lipolysis is increased as increased cortisol and catecholamines
Generates fatty acids which drive ketone production

Question 20

What ketone is produced in alcoholic ketoacidosis?

Answer 20

Beta-hydroxybutyrate

Question 21

What is the affect of increased FFAs?

Answer 21

Inhibits processing of acetyl CoA in Krebs cycle which further drives ketone production

Question 22

What is the effect of raised NADH?

Answer 22

Reduces gluconeogenesis

Question 23

What is the treatment for AKA?

Answer 23

Fluids
Dextrose slowly
Thiamine
Correct electrolyte imbalance - watch for refeeding syndrome

Question 24

What is the triad of Wernicke’s/ Korsakoff’s?

Answer 24

Gate ataxia or imbalance, ophthalmoplegia/ nystagmus and confusion

Question 25

What is the effect of lack of thiamine?

Answer 25

Krebs cycle stalls, switch from aerobic to anaerobic respiration
This produces far less ATP and lactate is the bi-product - focal acidosis (areas involved in motor control and cognition)

Question 26

How much thiamine is stored in the liver?

Answer 26

5-10 day supply