lecture 12 - microcytic anaemias & iron Flashcards
What are the 3 main causes of microcytic anaemias?
Iron deficiency, Thalassaemias, Inflammation
How can iron deficiency and thalassaemia be distinguished from each other in presentations of microcytic anaemia?
Patients with iron deficiency will have low serum ferritin, while those with thalassaemia will have normal ferritin.
Where is iron stored in the body?
Inside ferritin, which is in tissues and circulating
How is iron carried in the blood ?
Bound to transferrin
What happens to transferrin levels in iron deficiency?
Body responds by increasing levels of transferrin, although they will have reduced saturation
What are the causes of iron deficiency?
Inadequate diet, blood loss (menstruation, GI bleed, haemorrhage), growth (pregnancy, children/adolescents), malabsorption
Which populations are most at risk of iron deficiency?
Menstruating women, pregnant women, elderly (increased risk of GI cancer/bleeding)
How is iron defiency treated?
Increased iron in diet (and increase Vitamin C), oral iron tablets/syrup, iron infusion
How can dietary/supplemental iron absoprtion be optimised?
Consuming iron-rich foods/tabletswith foods rich in Vitamin C (e.g. orange juice), not taking iron with coffee or tea. take in morning, and on alternating days
What are some of the causes of failure to respond to oral iron treatment in iron deficiency?
failure to treat underlying cause, malabsorption, mixed deficiency
Where is iron absorbed in the gut?
Small intestine - duodenum and jejunum
What is the ‘iron gate’ for iron absoprtion?
Ferroportin
How does hepcidin influence gut absoprtion of iron?
At high levels it closes the ferroportin ‘gate’ preventing uptake of iron - reduces absorption. And vice versa (low hepcidin = increased absorption)
Why is less iron absorbed in an inflammatory state?
Inflammation causes release of hepcidin, which reduces absorption by blocking ferroportin in the absorptive cells of the gut
Why does the body release hepcidin in response to bacterial infection?
To reduce iron availability to bacteria - can help prevent bacterial growth
