Paeds haematology Flashcards
Why is iron required in the body?
The bone marrow requires iron to produce haemoglobin
There are several scenarios where iron stores can be used up and the patient becomes iron deficient:
Dietary insufficiency. This is the most common cause in children.
Loss of iron, for example in heavy menstruation
Inadequate iron absorption, for example in Crohn’s disease
Iron is mainly absorbed in the
duodenum and jejunum
Conditions that result in inadequate iron absorption
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Conditions that result in inflammation of the duodenum or jejunum such as coeliac disease or Crohn’s disease can also cause inadequate iron absorption.
Which medications can interfere with iron absorption
Iron requires the acid from the stomach to keep the iron in the soluble ferrous (Fe2+) form. When there is less acid in the stomach, it changes to the insoluble ferric (Fe3+) form. Therefore, medications that reduce the stomach acid, such as proton pump inhibitors (lansoprazole and omeprazole) can interfere with iron absorption.
Management of iron deficiency anaemia in children
Total iron binding capacity (TIBC) basically means
total space on the transferrin molecules for the iron to bind. Therefore, total iron binding capacity is directly related to the amount of transferrin in the blood.
transferrin saturation is
If you measure iron in the blood and then measure the total iron binding capacity of that blood, you can calculate the proportion of the transferrin molecules that are bound to iron. This is called the transferrin saturation. It is expressed as a percentage. The formula is:
Transferrin Saturation = Serum Iron / Total Iron Binding Capacity
Iron travels around the blood in which form
ferric ions (Fe3+) bound to a carrier protein called transferrin
Ferritin is the form that iron takes when
Ferritin is the form that iron takes when it is deposited and stored in cells.
Extra ferritin is released from cells when
when there is inflammation, such as with infection or cancer.
If ferritin in the blood is low, this is highly suggestive of
iron deficiency
High ferritin is indicative of:
High ferritin is difficult to interpret and is likely to be related to inflammation rather than iron overload. A patient with a normal ferritin can still have iron deficiency anaemia, particularly if they have reasons to have a raised ferritin, such as infection.
Serum iron indicates and varies with:
Serum iron varies significantly throughout the day, with higher levels in the morning and after eating iron containing meals. On its own serum iron is not a very useful measure.
Transferrin saturation gives a good indication of
Transferrin saturation gives a good indication of the total iron in the body. In normal adults it is around 30%, however if there is less iron in the body, transferrin will be less saturated. When iron levels go up, transferrin will be more saturated. It can increase shortly after eating a meal rich in iron or taking iron supplements, so a fasting sample is better.
total iron in the body can be measured best how?
tranferring saturation
Two things can increase the values of all iron results including serum ferritin and serum iron (except for …, which will be low), giving the impression of iron overload:
Supplementation with iron
Acute liver damage (lots of iron is stored in the liver)
Thalassaemia cause
Thalassaemia is related to a genetic defect in the protein chains that make up haemoglobin
Is Thalassaemia a recessive or dominant condition?
autosomal recessive
Thalassaemia potential signs and symptoms
- Microcytic anaemia (low mean corpuscular volume)
- Fatigue
- Pallor
- Jaundice
- Gallstones
- Splenomegaly
- Poor growth and development
- Pronounced forehead and malar eminences
Thalassaemia diagnosis
Thalassaemia patients have serum ferritin levels monitored to check for…
Iron overload occurs in thalassaemia as a result of the faulty creation of red blood cells, recurrent transfusions and increased absorption of iron in the gut in response to anaemia.
Management of iron overload involves
limiting transfusions and performing iron chelation.
Iron overload in thalassaemia causes which effects
Alpha-thalassaemia is caused by
Alpha-thalassaemia is caused by defects in alpha globin chains. The gene coding for this protein is on chromosome 16.
Alpha-Thalassaemia management
Beta-Thalassaemia is caused by?
Beta-thalassaemia is caused by defects in beta globin chains. The gene coding for this protein is on chromosome 11.