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MEH > Lecture 8- Iron Metabolsim > Flashcards

Lecture 8- Iron Metabolsim Flashcards

1
Q

What are the causes of microcytic anaemias?

A

TAILS

Thalassaemia
Anaemia of chronic disease 
Iron deficiency 
Lead poisoning 
Sideroblastic anaemia
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2
Q

Good dietary sources of haem and non haem iron?

A 
Haem:
Liver
Kidney
Beef burger or steak
Chicken 
Duck 
Pork chop
Salmon/ tuna 
Non haem:
Fortified cereals
Beans 
Barley 
Oats 
Rice 
Potatoes
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3
Q

Overview of iron absorption, transport, uptake, storage and metabolism?

A

Converted from ferric form (fe3+) to ferrous form (Fe2+) by the acidic stomach environment (helped by vit c). Can be stored as Fe3+ in ferritin. Can be released into blood through ferroportin which is inhibited by hepcidin. Transported around blood by transferrin in Fe3+ form. Taken into cell by transferrin receptor through endocytosis. Can then be stored or exported through ferroportin or used as a co-factor in mitochondria. Macrophages consume old RBCs and recycle iron by releasing it through ferroportin.

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4
Q

How odes iron overload occur?

A

Exceeds binding capacity of transferrin and is deposited in organs as haemosiderin. Free iron can cause oxidative stress. Damages liver, pancreas and causes cardiomyopathy

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5
Q

How is heriditary haemochromatosis caused and treated?

A

Caused by defect in HFE gene which normally inhibits transferrin receptor from taking up iron from bound transferrin. Also means that hepcidin is not inhibited which inhibits ferroportin. Iron accumulates in organs as haemosiderin and causes damage. Treat through venesection

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6
Q

How are microcytic anaemias borough about?

A

Reduced haem synthesis and reduced globin chain synthesis (thalassaemia)

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7
Q

What do microcytic cells look like?

A

Pale and hypochromic

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8
Q

Can iron be excreted?

A

No, can only control how much is absorbed

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9
Q

What are the two states of iron?

A

Ferric (Fe3+) isn’t absorbed and ferrous Fe2+ which is absorbed

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10
Q

Difference between haem and non haem iron?

A

Haem is all ferrous while non haem is a mixture of ferrous and ferric

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11
Q

How much iron required daily in diet?

A

Between 10-15mg

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12
Q

Effect of anaemia of chronic disease on iron absorption?

A

Iron will be absorbed into epithelial cell but increased hepcidin production due to inflammatory cells means that ferroportin will be inhibited from transporting it from epithelial cells into blood

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13
Q

What has negative and positive influences on the absorption of iron orally?

A 
Negative-
Fibre 
Tannins (tea)
Phytates
Antacids (gaviscon)

Positive
Vitamin C and citrate

Should take glass of orange juice with oral iron tablet

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14
Q

What are the two examples of stored iron?

A

Ferritin which is soluble

Haemosiderin which is aggregates of clumped ferritin particles and is insoluble damaging

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15
Q

How is iron taken 9into cells?

A

Transferrin receptor, endocytosis, sent to ferritin, mitochondria or released from cell through ferroportin

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16
Q

How is iron transported in blood?

A

Through transferritin which binds ferric iron

17
Q

Effect of hepcidin on iron absorption?

A

Inhibits it through inhibiting ferroportin

18
Q

Effect of anaemia of chronic disease on iron?

A

Hepcidin prevents ferroportin releasing iron both from cells and macrophages.

Hepcidin inhibits EPO production in the kidneys

Results in inhibited erythropoeisis and microcytic anaemia

19
Q

Overview of iron homeostasis?

A

Lose 1-2 mg per day
Gain 1-2 mg per day (can only absorb 10% from diet.
20mg recycled by macrophages and 20mg used in erythropoeisis

20
Q

Causes of iron deficiency?

A 
Insufficient intake (vegan)
Malabsorption 
Bleeding
Increased requirement 
Anaemia of chronic disease
21
Q

Who’s at risk of iron deficiency?

A

Women of child bearing age

Children

Geriatrics
Infants

22
Q

Signs and symptoms of anaemia?

A 
Tiredness
Heart failure 
Tachycardia 
Pallor
Increased respiratory rate 
Light headedness
Reduced exercise tolerance
23
Q

What to look out for in an iron deficiency FBC?

A

Low reticulocyte haemoglobin CHr

Low serum ferritin and raised total iron binding capacity (TIBC)

Lowered MCV

Lowered MCHC

24
Q

What does iron deficiency anaemia look like in blood smear?

A

Hypochromic and microcytic

25
Q

How to test for iron deficiency?

A

CHr and reduced plasma ferritin

26
Q

How do you treat iron deficiency?

A

Oral iron

Intramuscular

Blood transfusions

Intravenous iron

27
Q

What is transfused associated haemosiderosis?

A

Repeated blood transfusions results in iron accumulation. Haemosiderin damages liver, pancreas etc and makes skin look grey

MEH (17 decks)

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