Iron Poisoning ✅

Question 1

Why is iron poisoning a significant cause of toxicological mortality in young children?

Answer 1

Due to its presence in the environment as a result of supplementation for pregnant and breastfeeding mothers

Question 2

What is broadly related to the severity of iron toxicity?

Answer 2

The amount of elemental iron ingested

Question 3

Generally, ingestion of what amount of elemental iron will cause toxic effects?

Answer 3

10-20mg/kg

Question 4

Generally, ingestion of what amount of elemental iron can lea to severe effects and potential death?

Answer 4

50-60mg/kg

Question 5

What causes toxicity in iron overdose?

Answer 5

Total iron binding capacity is saturated, and free ferric iron (Fe3+) is present. This leads to production of hydroxyl free radicals, causing lipid peroxidation, which results in local tissue injury

Question 6

What are the primary sites of local tissue injury in iron overdose?

Answer 6

The gut and liver

Question 7

What are the initial symptoms of iron toxicity?

Answer 7

• Nausea and vomiting, with possible haematemesis
• Diarrhoea
• Abdominal pain

Question 8

What might happen following the initial symptoms of iron toxicity?

Answer 8

They may be an improvement in symptoms

Question 9

What is the problem with the initial improvement in symptoms after the initial phase of iron toxicity?

Answer 9

Can mask evolving raised anion gap metabolic acidosis

Question 10

What causes the raised anion gap metabolic acidosis in iron toxicity?

Answer 10

Disturbance of mitochondrial function

Question 11

What can occur following the metabolic acidosis in iron toxicity?

Answer 11

Multi-organ failure

Question 12

What is the often the first organ to be affected in iron toxicity?

Answer 12

Liver

Question 13

Why is the liver often the first organ to be affected in iron toxicity?

Answer 13

As a result of early exposure during first pass metabolism

Question 14

How might the GI system be affected in iron poisoning?

Answer 14

In survivors of severe iron poisoning, intestinal mucosal injury may lead to the formation of strictures

Question 15

Where is the most common location for strictures caused by iron poisoning?

Answer 15

Pylorus of the stomach

Question 16

What investigation may be useful in predicting toxicity in asymptomatic iron poisoning patients?

Answer 16

Serum iron concentrations 4 hours after ingestion

Question 17

At what serum iron concentration 4 hours after ingestion would significant toxicity be very unlikely?

Answer 17

Under 60µmol/L (following administration of immediate release preparations)

Question 18

Why might measurement of serum concentrations of iron after 4 hours underestimate toxicity?

Answer 18

Due to redistribution of iron to tissues and binding to ferritin

Question 19

When might serial serum iron concentrations be useful?

Answer 19

• Monitoring asymptomatic patients

- Monitoring those who have ingested slow release or enteric coated formulations

Question 20

Is activated charcoal useful in iron poisoning?

Answer 20

No

Question 21

Why is activated charcoal not useful in iron poisoning?

Answer 21

It is not absorbed by activated charcoal

Question 22

What are the treatment options for iron poisoning?

Answer 22

• Whole bowel irrigation

- Desferrioxamine

Question 23

How does whole bowel irrigation help in iron poisoning?

Answer 23

It may be effective in reducing absorption

Question 24

When is whole bowel irrigation recommended in iron poisoning?

Answer 24

Ingestions of >60mg/kg of elemental iron

Question 25

What is desferrioxamine?

Answer 25

A bacterially-derived iron chelating agent

Question 26

How does desferrioxamine help in iron poisoning?

Answer 26

It binds free iron and enhances its elimination in urine

Question 27

When is desferrioxamine indicated in iron poisoning?

Answer 27

All cases with signs of systemic intoxication, especially those with raised anion gap metabolic acidosis

Question 28

Should you wait for serum iron concentration results before starting treatment with desferrioxamine in patients with symptomatic iron poisoning?

Answer 28

No

Question 29

How long should desferrioxamine treatment be continued for in iron poisoning?

Answer 29

Until acidosis is reversed and patient is asymptomatic

Question 30

Why do you need to continue until the patient is asymptomatic when treating iron poisoning with desoferrioxamine?

Answer 30

Desferrioxamine interferes with most laboratory assays for serum iron and therefore this measure cannot be used to monitor response to therapy