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Year 2 - MCD - Haematology > Iron Deficiency > Flashcards

Iron Deficiency Flashcards

1
Q

What are some iron containing proteins in the body?

A
  • Hb
  • Myoglobin
  • Catalase
  • cytochrome p450
  • cycle-oxygenase
  • cytochrome a,b,c
  • ribonucleotide reductase
  • succinate dehydrogenase
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2
Q

Where is most of the body’s iron?

A

In haemoglobin

-> most crucial consequences of iron def are seen in the blood and also: you become iron deficient before you become anemic

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3
Q

In what part of Hb is iron?

A

It is in the haem component and carries oxygen

Hb = 4 globin chains and one haem group

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4
Q

How much iron do you need in a day to re-make huge numbers of RBCs on a daily basis?

A

20mg/day but fortunately Iron is recycled -> we only need a fraction of that through digestion.

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5
Q

How much iron do men and women need every day?

A

Men - 1mg
Women - 2mg

-> loss through desquamated cells of skin and gut as well as menstruation

(generally 12-15mg in human diet every day)

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6
Q

Where is iron found

A
  • Meat and fish(haem iron)
  • Vegetables
  • Whole grain cereal
  • chocolate

-> one of the most abundant chemicals in food.

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7
Q

In what state can we absorb Fe?

A

Fe2+

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8
Q

How can beverages alter the form iron is consumed in?

A
  • orange juice: you are more likely to absorb iron in the Fe2+ form
  • tea : you are more likely to absorb iron in the Fe3+ form.
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9
Q

What are the factors that affect iron absorption?

A 
DIET:
-  increase in haem iron
- ferrous iron
INTESTINE:    
- acid (duodenum)
- ligand (meat)
SYSTEMIC:
- iron deficiency	
- anaemia/hypoxia
- pregnancy

If you are pregnant or iron deficientt you will absorb more iron.

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10
Q

How is iron absorbed?

A
  • in the enterocytes
  • first duodenal cytochrome B transforms Fe3+ into Fe2+
  • Fe2+ can enter the cells via DMT-1 (divalent metal transporter)
  • Fe is eatery stored as ferritin inside the cell (first converted to Fe3+) or exit the cell into the blood via Ferroportin.
  • Hepcidin inhibits ferroportin and therefore decreases the amount of iron that goes into the blood
  • Iron transported in blood as transferrin by binding to apoferritin
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11
Q

High iron -> ? hepcidin - ?FP -> ? absorption

A

High iron -> high hepcidin - low FP -> low absorption

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12
Q

How much transferrin Is usually saturated with Fe?

A

50%

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13
Q

What 3 transferrin values might labs measure?

A
  1. Transferrin
  2. Total iron binding capacity, TIBC
  3. Transferrin saturation
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14
Q

What does erythropoietin cause?

A
  1. survival
  2. growth
  3. differentiation
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15
Q

What causes increase in erythropoietin?

A

Anemia -> hypoxia -> increase in erythropoietin _> RBC precursors

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16
Q

What is ACD?

A
  • Anemia in ill patients

- there is no obvious cause except that the patient is ill.

17
Q

Laboratory signs of being ill

A
  1. high CRP -> infection
  2. ESR increased
  3. Acute phase response: increases in the following
    - ferritin
    - FVIII
    - fibrinogen
    - immunoglobulins
18
Q

What are some conditions associated with ACD?

A
  • Chronic infections e.g. TB/HIV
  • Chronic inflammation e.g. RhA/SLE
  • Malignancy
  • Miscellaneous e.g. cardiac failure
19
Q

What is the pathogenesis of ACD?

A
  • cytokine release -> cytokines prevent the usual flow of iron from the duodenum, to red cells.
20
Q

What specifically do cytokines do in ACD?

A
  1. Stop erythropoietin increasing
  2. Stop iron flowing out of cells
  3. Increase production of ferritin
  4. Increase death of red cells

Therefore:- make less red cells

  • more red cells die
  • less availability of iron (stuck in cells/ferritin)
  • include TNF-alpha and interleukins
21
Q

What are some causes of iron deficiency?

A
  1. BLEEDING (e.g. GI or menstrual)
  2. increased use e.g. growth/pregnancy
  3. dietary deficiency e.g. vegetarians
  4. malabsorption e.g. coeliac
22
Q

When would you do full GI investigations in a patient with iron disease?

A
  • no coeliac antibodies
  • good diet
  • male
  • women over 40
  • post menopausal women
  • women with scanty menstrual loss
23
Q

What are full GI investigations?

A
  • Upper GI endoscopy - oesophagus, stomach, duodenum
  • Take duodenal biopsy
  • Colonoscopy
  • IF FIND NOTHING
    • small bowel meal and follow through
24
Q

What aside from GI investigations can be checked in patients with iron deficiency?

A
  • Menstruating woman <40 ….if heavy periods OR multiple pregnancies and no GI symptoms do nothing
  • ? Urinary blood loss
  • Antibodies for coeliac disease

any bleeding will gradually decrease iron stores.

25
Q

What are lab parameters that are checked in iron deficiency?

A
  1. MCV (mean cell volume)
  2. Serum iron
  3. Ferritin
  4. Transferrin (= total iron binding capacity, TIBC)
  5. Transferrin saturation

other parameters:

  • Serum iron
  • Ferritin
  • Transferrin (TIBC)
  • transferrin saturation
26
Q

What are causes of low MCV?

A
  1. Iron deficiency
  2. Thalassaemia trait
  3. Anaemia of chronic disease (low or N)
27
Q

What are serum iron levels in IDA, ACD and thalassemia?

A

IDA and ACD: low

thalassemia trait: normal

28
Q

How do you confirm thalassemia trait?

A
  • Hb ele ctrophoresis

- confirms an additional type of Hb is present

29
Q

What lab clues indicate that ferritin is not ideal?

A

Raised CRP

Raised ESR

30
Q

What happens to transferrin in iron deficiency and in chronic disease?

A
  • IDA: high, you make more transferrin

- ACD: normal or even low, you might not make protein as well when you are sick.

31
Q

Further investigations in iron deficiency anemia?

A 
Endoscopy and colonoscopy
Duodenal biopsy
Anti-helicobacter antibodies
Anti-coeliac antiodies
		? Abdo ultrasound to look at kidneys
		? Dipstick urine
		? Pelvic ultrasound to exclude fibroids
32
Q

What patients should definitely get a full GI investigation?

A

Men of any age with low ferritin

This suggests iron deficiency and he needs to have upper and lower GI endoscopies to look for a source of bleeding

33
Q

Classic iron deficiency blood results

A 
Hb - low
MCV - low
Serum iron - low
ferritin - low
transferrin - high
TF saturation - low
34
Q

Classic ACD blood results

A 
Hb - LOW
MCV - LOW or N
Serum iron - LOW
Ferritin - HIGH or N
Transferrin - normal/low
Transferrin saturation - normal
35
Q

Thalassemia blood results

A 
Hb - low
MCV - low
Serum iron - normal
Ferritin - normal
TF - normal
TF saturation - normal
36
Q

Blood film in iron deficieny

A

long thin cells, not only round ones

more central pallor?

37
Q

What can you do if you looked at blood results and film and dont know the cause?

A

give iron and see if the patient gets better

Year 2 - MCD - Haematology (11 decks)

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