Iron in Health and Disease Flashcards

1
Q

where does iron absoprtion occur?

A

mainly in duodenum

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2
Q

how does absorbic acid affect iron absorption?

A

enhances absoprtion

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3
Q

what dietary items can inhibit iron absoprtion?

A

tannins (tea)

phytates (cereals/bran)

calcium (dairy)

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4
Q

how does duodenal cytochrome B (found in luminal surface) affect iron?

A

reduced Fe3+ to Fe2+

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5
Q

what is the function of ferroportin?

A

facilitates iron export from the enterocyte,

then passed onto transferrin for transport somewhere else

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6
Q

what is produced in the liver in response to iron load and inflammation?

A

hepcidin

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7
Q

how is iron status assessed?

A

funcitonal iron

transport iron/supply to tissues

storage iron

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8
Q

how is functional iron measured?

A

Hb Concentration

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9
Q

how is transport iron measurede?

A

% saturation of transferrin with iron

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10
Q

how is storage iron measured?

A

serum ferritin

tissue biopsy

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11
Q

what protein is used to transport iron?

A

transferrin

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12
Q

what are th bound and unbound forms of transferrin?

A

bound → holotransferrin

unbound → apotransferrin

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13
Q

what other circumstances can serum ferritin be raised?

A

infection

malignancy

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14
Q

what are some causes of iron deficiency?

A

insufficient intake

malabsoprtion

bleeding

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15
Q

what is iron malutilisation?

A

anaemia of chronic disease

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16
Q

what are some causes of chronic blood loss that could result in iron deficeincy anaemia?

A

menorrhagia

GI (tumour/ulcer)

haematuria

17
Q

what is primary iron overload?

A

long term excess iron absoprtion with parenchymal rather than macrophage iron loading

18
Q

what disease can cause primary iron overload?

A

hereditary haemochromatosis

19
Q

what gene is mutated in hereditary haemochromatosis?

A

HFE gene

20
Q

how does hereditay haemochromatosis cause iron overload?

A

decreased synthesis of hepcidin → inc iron absoprtion

21
Q

what are some clinical features of hereditary haemochromatosis?

A

fatigue

joint pain

cirrhosis

cardiomyopathy

middle age onset

22
Q

how can hereditary haemochromatosis be diagnosed?

A

trasnferrin sat >50%

serum ferritn >300g/l

liver biopsy

23
Q

what is the treatment fro hereditary haemochromatosis?

A

weekly venosection to exhaust iron stores then keep ferritin <50ug

24
Q

who gets screened fro hereditary haemochromatosis?

A

family screenign fro first degree relatives

25
Q

what causes secondary iron overload?

A

iron-loading anaemias

26
Q

what can cause secondary iron-loading anaemias?

A

repeated red cell transfusions

overactive eryhtropoiesis

27
Q

what is the treatment for secondary iron ovreload?

A

venesection- not option in alreayd anaemic pateints

iron chelating agents

28
Q

name a chelating agent?

A

desferrioxamine