Ethylene Glycol and Other Toxic Alcohol Poisoning ✅

Question 1

What are the characteristics of ethylene glycol?

Answer 1

• Odourless

- Sweet tasting

Question 2

What happens if ethylene glycol is ingested?

Answer 2

Has significant toxicity, even in small amounts

Question 3

What volume of ethylene glycol ingested can have significant toxicity in a 20kg child?

Answer 3

<5ml

Question 4

What is ethylene glycol metabolised into?

Answer 4

Glycoaldehyde

Question 5

What enzyme is involved in the metabolism of ethylene glycol to glycoaldehyde?

Answer 5

Alcohol dehydrogenase

Question 6

What is glycoaldehyde metabolised into?

Answer 6

Glycolic acid

Question 7

What enzyme is involved in the metabolism of glycoaldehyde to glycolic acid?

Answer 7

Aldehyde dehydrogenase

Question 8

What is glycolic acid metabolised into?

Answer 8

Glyoxylic acid

Question 9

What enzyme is involved in the metabolism of glycolic acid to glyoxylic acid?

Answer 9

Lactate dehydrogenase

Question 10

What is glyoxylic acid metabolised into?

Answer 10

Oxalic acid

Question 11

What enzyme is involved in the metabolism of glyoxylic acid to oxalic acid?

Answer 11

Xanthine oxidase

Question 12

What are the phases of ethylene glycol poisoning?

Answer 12

• 0.5-12 hours
• 12-36 hours
• 24-72 hours

Question 13

What happens 0.5-12 hours after ethylene glycol ingestion?

Answer 13

Intoxicated appearance;

• Dizziness
• Incoordination
• Slurred speech
• Confusion
• Nausea/vomiting

Question 14

What causes the symptoms 0.5-12 hours following ethylene glycol ingestion?

Answer 14

Unmetabolised ethylene glycol

Question 15

What is seen 12-36 hours after ethylene glycol ingestion?

Answer 15

• Tachycardia
• Hypertension
• Raised anion gap metabolic acidosis with compensatory hyperventilation

Question 16

What causes the clinical features 12-36 hours after ethylene glycol ingestion?

Answer 16

Accumulation of glycolic and oxalic acid

Question 17

What is seen 24-72 hours after ingestion of ethylene glycol?

Answer 17

Signs and symptoms of renal failure

Question 18

What causes renal failure in ethylene glycol poisoning?

Answer 18

Probably deposition of calcium oxalate crystals in the kidney

Question 19

What are the antidotes to ethylene glycol poisoning?

Answer 19

• Alcohol

- Fomepizole

Question 20

How does alcohol act as an antidote to ethylene glycol?

Answer 20

It has a much higher affinity for alcohol dehydrogenase than ethylene glycol

Question 21

How does fomepizole act as an antidote to ethylene glycol?

Answer 21

It is a potent inhibitor of alcohol dehydrogenase

Question 22

How does the prevention of metabolism of ethylene glycol by alcohol or fomepizole reduce toxicity of ethylene glycol?

Answer 22

It prevents formation of toxic metabolites, and ethylene glycol is gradually excreted unchanged in the urine

Question 23

What are the advantages of fomepizole over alcohol in ethylene glycol poisoning?

Answer 23

It does not cause intoxication or hypoglycaemia

Question 24

What is the disadvantage of fomepizole over alcohol in the treatment of ethylene glycol poisoning?

Answer 24

It is significantly more expensive

Question 25

What other substance can alcohol or fomepizole be used as the antidote for?

Answer 25

Methanol

Question 26

Why can alcohol or fomepizole also be used as the antidote for methanol poisoning?

Answer 26

Methanol is also metabolised by alcohol dehydrogenase

Question 27

What is methanol metabolised into with alcohol dehydrogenase?

Answer 27

Formaldehyde

Question 28

What is formaldehyde metabolised into?

Answer 28

Formic acid

Question 29

What enzyme is involved in the metabolism of formaldehyde into formic acid?

Answer 29

Aldehyde dehydrogenase

Question 30

What is formic acid metabolised into?

Answer 30

CO2 + H2O