Lecture 20: Iron Status 1 Flashcards
What are some functions of iron?
- Oxygen carrying (Haemoglobin)
- Oxygen storage (Myoglobin)
- Oxidative production cellular energy
- Glycolysis in muscles
What are consequences of iron deficiency anaemia?
- Decreased work capacity
- Fatigue
- Behavioural disturbances
- Decreased cognitive function
- Decreased growth
- Spoon-shaped nails
What are symptoms of non-anaemic iron deficiency?
There are questions to what symptoms could look like:
- Decreased cognitive function?
- Fatigue?
- Decreased mood?
- Decreased work capacity?
What is one symptom we know for sure for non-anaemic iron deficiency?
Increased risk of iron deficiency anaemia
What is aetiology?
refers to the study of the cause or origin of a disease or medical condition
What is the aetiology of iron deficiency?
- Low intake or poor absorption
- High requirements: growth, blood loss, pregnancy
What are groups at risk of iron deficiency?
- Infants
- Toddlers
- Menstruating women
- Pregnant women
- Blood loss
- Vegetarians
What is the best assessment of iron status?
Biochemical assessment
Why is biochemical assessment the best assessment of iron status?
Because the amount of iron you absorb is massively influenced by current status, enhancers and inhibitors
- You have to do a biochemical assessment to know if someone is deficient
- CANNOT just go off dietary assessment
What will happen to haemoglobin red cell indices in the presence of iron deficiency anemia?
Haemoglobin will DECREASE
What will happen to hematocrit red cell indices in the presence of iron deficiency anemia?
Hematocrit will DECREASE
What will happen to mean cell volume red cell indices in the presence of iron deficiency anemia?
Mean cell volume will DECREASE
What will happen to red cell distribution width red cell indices in the presence of iron deficiency anemia?
Red cell distribution width will INCREASE
What will happen to erythrocyte protoporphyrin red cell indices in the presence of iron deficiency anemia?
Erythrocyte protoporphyrin will INCREASE
What are the red cell indices? (5)
- Haemoglobin
- Haematocrit
- Mean cell volume
- Red cell distribution width
- Erythrocyte protoporphyrin (FEP or ZPP)
What is haemoglobin?
a protein in red blood cells responsible for transporting oxygen
What is haematocrit?
“packed cell volume” - the percentage of red blood cells in a given volume of blood
What is mean cell volume?
The average size or volume of red blood cells in a blood sample (Ht/RBC)
What is red cell distribution width?
a measure of the variation in size or volume of red blood cells in a blood sample
What is erythrocyte protoporphyrin (FEP or ZPP)?
a precursor molecule in hemoglobin production
Why does haemoglobin decrease during anaemia?
Iron is a major component of Haemoglobin
Why does mean cell volume decrease during anaemia?
If you don’t have enough iron to make Haemoglobin you will get anaemic looking blood cells, they are going to be small. This means that the mean cell volume will be smaller
Why does haematocrit decrease during anaemia?
If you don’t have enough RBC’s your cells will be smaller, therefore the volume will be smaller
Why does red cell distribution width increase during anaemia?
because the body produces red blood cells of varying sizes in response to the underlying cause of the anemia
Why does erythrocyte protoporphyrin increase during anemia?
During immature stage in the production of Haemoglobin the heme molecule has not formed yet and there is a zinc iron in there waiting to be replaced, if you don’t have enough iron the zinc will not get bumped off and instead of having heme, you have more erythrocyte protoporphyrin.
What are the biochemical indices?
- Serum ferritin
- Soluble transferrin receptor
- Serum iron
- Total iron binding capacity
- Transferrin saturation
What happens to serum ferritin during iron deficiency?
Will decrease
What happens to soluble transferrin receptors during iron deficiency?
Will increase
What will happen to serum iron during iron deficiency?
Will decrease
What will happen to total iron binding capacity during iron deficiency?
Will increase
What will happen to transferrin saturation during iron deficiency?
Will decrease
Why does serum ferritin decrease during iron deficiency?
because it reflects the body’s stored iron levels
Why do soluble transferrin receptors increase during iron deficiency?
because they are produced by cells in response to low iron availability, reflecting an increased demand for iron transport and uptake by tissues when iron stores are depleted
Why does Serum Fe decrease during iron deficiency?
Because the body lacks sufficient iron to maintain normal levels of circulating iron
Why does total iron binding capacity increase during iron deficiency?
because the body compensates for low iron levels by producing more transferrin, a protein that transports iron, in an effort to maximize iron absorption and transport
Why does transferrin saturation decrease during iron deficiency?
because there is less iron available to bind to transferrin
What are soluble transferrin receptors?
a form of transferrin receptors released into the bloodstream from cells that indicate the demand for iron in the body, with elevated levels often reflecting iron deficiency
What is transferrin saturation?
a laboratory measure that reflects the percentage of transferrin that is bound to iron, indicating the availability of iron for use in the body
What is transferrin?
the main iron transport protein in the blood
How many stages of iron deficiency are there?
3
What is stage 1 of iron deficiency?
Depleted iron stores - storage iron deficiency
What is stage 2 of iron deficiency?
Iron deficient erythropoiesis
What is stage 3 of iron deficiency?
Iron deficiency anaemia
What happens to haemoglobin during the stages of iron deficiency?
Stage 1 = Normal
Stage 2 = Normal
Stage 3 = Decreased
What happens to serum ferritin during the stages of iron deficiency?
Decreased in all 3 stages
What happens to erythrocyte protoporphyrin (EP) during the stages of iron deficiency?
Stage 1 = Normal
Stage 2 = Increased
Stage 3 = Increased
What happens to transferrin saturation during the stages of iron deficiency?
Stage 1 = Normal
Stage 2 = Decreased
Stage 3 = Decreased
What are the 3 ways of interpreting iron indices?
- Cut-offs and reference limits
- Multi-parameter models
- Body iron model
What is a multi-parameter model?
framework that integrates multiple variables to analyze complex systems and predict outcomes based on the interactions among those variables
What is the multi-parameter model that is used to interpret iron indices?
The ferritin model
What ferritin model indicates iron deficient erythropoiesis (IDE)?
if 2 or more of SF, TS and EP are abnormal but their Haemoglobin is normal.
What ferritin model indicates iron deficiency anaemia (IDA)?
if 2 or more of SF, TS and EP are abnormal AND their Haemoglobin is low
What is the body iron model?
Equation based on ratio of transferrin receptor and serum ferritin
What are the advantages of the body iron model?
- Good estimate of body iron measured by phlebotomy
- Continuous variable
- Less affected by inflammation
What are the disadvantages of the body iron model?
- Cost
- No standard method
