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Year 2 haem mine > iron deficiency and anaemia of chronic disease > Flashcards

iron deficiency and anaemia of chronic disease Flashcards

1
Q

examples of iron containing proteins

A 
haemoglobin
myoglobin 
cytochromes 
catalase 
succinate dehydrogenase

BUT MOST IRON IS IN HB

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2
Q

role of iron in haemoglobin

A

CRUCIAL ROLE - holds onto oxygen

Most obvious consequences of iron deficiency are seen in the blood

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3
Q

what does low iron mean

A

Low iron = low Hb = Anaemia

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4
Q

what makes up haemoglobin

A

haem plus globin
Each haem group is associated with a single globin chain, and we can see a picture of the association here in this slide.

Haem sits in a pocket formed by the globin chain and in the final haemoglobin molecule, the haem groups are near the surface of the molecule.

Here we can see the structure of haem, which is responsible for the red colour of Hb

Essentially it consists of a ring of carbon, hydrogen and nitrogen atoms and in its centre is an iron atom in the ferrous (Fe2+) state.

Heme combines reversibly with oxygen

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5
Q

lifespan of red cells

A

120 days
To re-make huge numbers of red cells on a daily basis you need 20mg iron/day

Fortunately - Iron is recycled

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6
Q

how much iron do men and women need?

A

Men - need 1mg/day

Women - need 2mg/day

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7
Q

how do humans lose iron if a lot of iron is recycled?

A

Desquamated cells of skin and gut

BLEEDING - menstruation or pathological

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8
Q

what food contain lot of iron

A
  • Meat and fish(haem iron)
    - Vegetables
    - Whole grain cereal
    - chocolate
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9
Q

our diet contains a lot of iron so why are there problems?

A

Most iron eaten IS NOT ABSORBED

Can’t absorb ferric iron Fe3+
Can only absorb ferrous iron Fe2+
-orange juice helps

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10
Q

factors affecting absorption

A

DIET:
increase in haem iron ferrous iron

INTESTINE:
acid (duodenum)
ligand (meat)

SYSTEMIC:
iron deficiency anaemia/hypoxia
pregnancy

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11
Q

how is iron absorbed?

A

iron in diet is absorbed at the duodenum. Intracellularly iron turns to ferritin.
moves into plasma

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12
Q

how does the gut cell alter iron absorption?

A

ferroportin is essential for transporting iron at bottom of enterocytes. Amount of ferroportin depends on hepcidin.
hepcidin binds to ferroportin and destroys it.
SO
High iron - high hepcidin - low ferroportin- low absorption

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13
Q

what does transferrin do?

A 
holds onto iron in the circulation 
can be measured: 
1. Transferrin
2. Total iron binding capacity, TIBC
3. Transferrin saturation
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14
Q

what does erythropoietin do to alter RBC count?

A 
Anaemia
Tissue hypoxia
Increase in erythropoietin
Red cell precursors
So that they: 
1. Survive   2. Grow    3. Differentiate
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15
Q

what is ACD

anaemia of chronic disease

A

Anaemia in patients who are unwell

bleeding? NO
marrow infiltrated? NO
iron/B12 or folate deficient? NO

NO OBVIOUS CAUSE EXCEPT THAT THE PATIENT IS ILL

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16
Q

what are the lab signs of being ill?

A 
C-reactive protein
Erythrocyte Sedimentation Rate
Acute phase response- increases in
			- ferritin
			- FVIII
			- Fibrinogen
			- immunoglobulins
17
Q

ACD: associated conditions

A

Chronic infections e.g. TB/HIV
Chronic inflammation e.g. RhA/SLE
Malignancy
Miscellaneous e.g. cardiac failure

18
Q

what is the importance of cytokines in ACD?

A

Cytokines prevent the usual flow of iron from duodenum to red cells

Block in iron utilisation

19
Q

cytokines do several things:

A
  1. Stop erythropoietin increasing
  2. Stop iron flowing out of cells
  3. Increase production of ferritin
  4. Increase death of red cells
20
Q

what happens as a result of cytokines in ACD?

A 
Therefore
		- make less red cells
		- more red cells die
		- less availability of iron 
				(stuck in cells/ferritin)
21
Q

what do cytokines include?

A

TNF alpha

interleukins

22
Q

causes of iron deficiency

A
  1. Bleeding e.g. menstrual/GI
  2. Increased use e.g. growth/pregnancy
  3. Dietary deficiency e.g. vegetarian
  4. Malabsorption e.g. coeliac
23
Q

when do you do full GI investigations?

A 
Good diet and no coeliac antibodies…..
Male
Women over 40
Post menopausal women
Women with scanty menstrual loss
24
Q

what are the full GI investigations?

A

Upper GI endoscopy - oesophagus, stomach, duodenum
Take duodenal biopsy
Colonoscopy

IF FIND NOTHING
- small bowel meal and follow through

25
Q

what are the lb parameters

A 
MCV (mean cell volume)
Serum iron
Ferritin
Transferrin 
(= total iron binding capacity, TIBC)
transferrin saturation
26
Q

3 causes of a low MCV

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

how do you confirm thalassaemia trait?

A
  • Haemoglobin electrophoresis

- confirms an additional type of haemoglobin is present

28
Q

what are the levels of ferritin in iron deficiency and chronic disease?

A

LOW in iron deficiency

HIGH in chronic disease

29
Q

can ferritin be normal despite def?

A

Ferritin can be normal DESPITE iron def

30
Q

lab clues that ferritin not ideal

A

Raised CRP

Raised ESR

31
Q

what happens to transferrin in iron deficiency and chronic disease?

A 
ID = transferrin goes up 
CD = normal or even low
32
Q

what happens to transferrin saturation in ID and CD?

A 
ID = low saturation 
CD = normal
33
Q

what to look for in a man of any age who presents with a low ferritin

A

Man of ANY AGE (even your age) with a low ferritin

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

34
Q 
Classic iron deficiency:
Hb					
MCV					Serum iron 			
Ferritin 				
Transferrin 			
Transferrin saturation
A 
Classic iron deficiency:
Hb					LOW
MCV					LOW
Serum iron 			LOW
Ferritin 				LOW
Transferrin 			HIGH
Transferrin saturation 	LOW
35
Q 
Anaemia of chronic disease:
Hb					?			
MCV					?
Serum iron 			?
Ferritin 				?
Transferrin 			?
Transferrin saturation 	?
A 
Classic anaemia of chronic disease:
Hb					LOW
MCV					LOW or N
Serum iron 			LOW
Ferritin 				HIGH or N
Transferrin 			normal/low
Transferrin saturation 	normal
36
Q 
thalassaemia trait
Hb					?			
MCV					?
Serum iron 			?
Ferritin 				?
Transferrin 			?
Transferrin saturation 	?
A 
Thalassaemia trait
Hb					LOW
MCV					LOW
Serum iron 			NORMAL
Ferritin 				NORMAL

Transferrin NORMAL
Transferrin saturation NORMAL

Year 2 haem mine (11 decks)

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