Iron deficiency COPY Flashcards
What is the largest store of iron?
Haemoglobin
What is the easiest way to detect iron deficiency?
Check the blood
Where is iron in the structure of haemoglobin?
In the centre of the haem group
What is the typical structure of haemoglobin?
4 haem groups with a globin chain associated to each haem group
What makes up the haem ring around the iron in the centre?
Carbon, hydrogen and nitrogen atoms
What is the daily required amount of iron?
20mg
Where does most of this iron come from?
It is much more than the amount that you consume so most of it is recycled
How is iron lost from the body?
Desquamated cells of the skin and gut
Bleeding
Menstruation- one of biggest causes in women
How much iron is in the diet per day?
12-15mg
What foods contain iron?
Meat and fish- haem iron
Vegetables
Whole grain cereal
Chocolate
What happens to most iron that is eaten and why?
It isn’t absorbed because the body can’t absorb ferric iron, only ferrous iron
What can affect the absorption of iron from the diet
Orange juice helps
Cups of tea will convert into ferric form
What factors will increase iron absorption?
Iron deficiency
Anaemia/hypoxia
Pregnancy
What happens to iron when it reaches the gut?
It will pass into epithelial cells but then there is control across the basement membrane of the epithelial cell
What do you need at the basement membrane of the epithelial cells to translate iron into the blood?
Ferroportin
What is hepcidin?
Regulator of the entry of iron into circulation
How does hepcidin work?
When you have high iron levels, you will have high hepcidin levels which will block the ferroportin and stop you from absorbing as much iron
How do the iron levels affect the levels of hepcidin?
Hepcidin is a group of proteins that have iron responsive elements within their gene so iron is part of the complex that switches on hepcidin transcription
What happens to iron when it enters epithelial cells?
It enters as elemental iron and a protein shell forms around it to form ferritin micelles
What happens to the iron once it enters the plasma via ferroportin?
It gets linked to transferrin which transports the iron around the body
What is the normal transferrin saturation with iron?
20-40%
Wha three things can be measured in relation to transferrin?
Transferrin amount
Total iron binding capacity
Transferrin saturation
Where is erythropoietin produced?
Kidneys
What happens in terms of erythropoietin if you are hypoxic?
Increase in erythropoietin secretion and hence increase in red blood cell precursors/RBCs
What is anaemia of chronic disease?
Anaemia seen in patients with chronic disease e.g. chronic infection, chronic immune activation or malignancy
How will the patient with anaemia of chronic disease present?
They will: Not be bleeding Not have any bone marrow infiltration Not be iron/B12 or folate deficient No obvious cause except being ill
What is the most commonly used sign of being ill?
C-reactive protein (CRP)
What is CRP?
Acute phase protein that increases in case of infection or inflammation
What other signs are used to detect illness?
Erythrocyte sedimentation rate (ESR)- rises in response Ferritin- increases Factor VIII Fibrinogen Immunoglobulins
Which immunoglobulin is high if you’re acutely ill?
IgG
What conditions are associated with anaemia of chronic disease?
Chronic infections
Chronic inflammation
Malignancy
Miscellaneous
What is anaemia of chronic disease due to?
Cytokine release that occurs when someone is unwell
What effect does cytokine release have?
Cytokines prevent the usual flow of iron from the duodenum to the red cells- they block iron utilisation by red cells Stop erythropoietin from increasing Stop iron flowing out of cells Increase production of ferritin Increase death of red cells
What do cytokines include?
TNF alpha
Interleukins
What are the 4 causes of iron deficiency?
Bleeding - e.g. menstrual/GI
Increased use- e.g. growth/pregnancy
Dietary deficiency- e.g. vegetarian
Malabsorption- e.g. coeliac disease
What are the three causes of a low MCV?
Iron deficiency
Thalassemia trait
Anaemia of chronic disease
If you were told that a patient had low serum iron, which of the three causes for low MCV would this rule out?
Thalassaemia (normal serum iron)
How would you confirm that a patient has thalassaemia?
Haemoglobin electrophoresis- would confirm there is an additional type of haemoglobin present
How would you differentiate between iron deficiency and ACD in a patient with low MCV and low serum iron?
Ferritin
Low- iron deficiency
High- ACD
Transferrin
Increases- iron deficiency
Normal or low- ACD
What does it mean if a man of any age has low ferritin?
They have iron deficiency
What are the parameters like in classic iron deficiency?
Hb- Low MCV- Low Serum iron- Low Ferritin- Low Transferrin- High Transferrin saturation- Low
What are the parameters like in classic thalassaemia trait?
Hb- Low MCV- Low Serum iron- Normal Ferritin- Normal Transferrin- Normal Transferrin sat- Normal
