Iron overload

Question 1

What are the 2 classes of iron overload?

Answer 1

Primary
Secondary

Question 2

What is the main cause of primary iron overload?

Answer 2

Hereditary haemochromatosis

Question 3

What are some possible causes of secondary iron overload?

Answer 3

Transfusion
Iron loading anaemia

Question 4

What is hereditary haemochromatosis?

Answer 4

This is the long term excess iron absorption with parenchymal (Iron build up in tissues) rather than macrophage iron loading

Question 5

Who is most commonly affected by hereditary haemochromatosis?

Answer 5

Those aged 30-50

Question 6

How does hereditary haemochromatosis occur?

Answer 6

Hereditary haemochromatosis is most commonly caused by mutations within the HFE gene, resulting in decreased synthesis of hepcidin

This means that more iron is absorbed, as hepcidin prevents iron absorption

This increased iron level will cause overload and eventual end organ damage

Question 7

What are some clinical features of hereditary haemochromatosis?

Answer 7

• Weakness
• Fatigue
• Joint pain
• Impotence
• Arthritis
• Cirrhosis
• Diabetes
• Cardiomyopathy (rare)

Question 8

How is hereditary haemochromatosis diagnosed?

Answer 8

• Genetic testing for HFE gene mutations and mutations of other iron regulatory proteins (e.g. ferroportin)
• Transferrin saturation >50%
• Serum ferritin >300ug (Men) or >200ug (Women)
• Liver biopsy (Rarely needed)

Question 9

How is hereditary haemochromatosis managed?

Answer 9

First line management is a weekly venesection, in which blood is removed form the body, resulting in a decrease in iron levels

Around 450-500ml of blood is released each week, with the initial im being to exhaust iron stores (Ferritin <20ug)

• Removal of iron
• Removal of 450-500ml blood per week
• Initial aim is to exhaust iron stores (Ferritin <20ug)

Family screening is usually performed in adult relatives for HFE genotype

Question 10

How can transfusions cause secondary iron overload?

Answer 10

Transfusions can lead to secondary iron overload, as each unit of blood contains around 250mg of blood

Question 11

What are some forms of iron loading anaemia?

Answer 11

Iron loading anaemias, such as thalassaemia, sideroblastic anaemia or myelodysplasia can cause secondary iron overload

Question 12

How is secondary iron overload managed?

Answer 12

Iron chelating drugs are usually given, such as desferrioxamine, which binds to iron and allows its excretion

Question 13

What are some endocrine complications of iron overload?

Answer 13

• Impaired growth and pubertal development
• Diabetes
• Osteoporosis

Question 14

What are some cardiac consequences of iron overload?

Answer 14

• Cardiomyopathy
• Arrhythmias

Question 15

What hepatic complication can occur in iron overload?

Answer 15

Hepatocellular cancer