iron deficiency and anaemia of CD Flashcards
where is most iron in the body found?
- most found in Hb
- found in heam part
- role to hold onto oxygen in Hb
how much iron do you need per day?
20mg iron/day to replace lost red cells BUT we can recycle iron
some iron lost via: desquamated cells of skin and gut, bleeding
- men need around 1mg/day, women need 2mg
how much iron does human diet provide?
12-15mg of iron/day
in meat and fish, veg, whole grain cereal
main iron eaten not absorbed as can only absorb ferrous
what are the factors that affect absorption?
- diet: inc. in haem iron
- intestine: acid in duodenum
- systemic: iron def
what are the factors that inc. iron absoprtion?
- iron def
- anaemia/hypoxia
- pregnancy
how does iron move into cell/blood?
- iron freely transports into cell but ferroportin facilitates transport of iron into blood
what does hepcidin do? what is the hepcidin level regulation?
- hepcidin inhibits ferroportin
- has iron responsive elements within their genes
- so iron is part of complex that switches on hepcidin transcription
where is ferroportin found?
- enterocytes of duodenum
- macrophages of spleen
- hepatocytes
describe iron absorption
- iron from diet taken into cell
- protein shell forms around it to form ferritin
- or can bin to transferrin in blood plasma
how much transferrin is saturated with iron?
20-40%
How does TF enter cell?
- cannot enter directly
- binds with TF-R and is internalised as a whole
- as pH drops, iron is released and transferrin receptors are recycled
why is TF important?
- iron is toxic and insoluble
- TF fixes this
what is EPO?
- produced in kidneys
- production inc. in response to hypoxia –> triggers more RBC precursors to be released
- RBCs precursors survive longer and will grow/differentiate
what is ACD?
- anaemia of chronic disease
- anaemia that is seen in patients with chronic disease
- pt not showing classic causes of anaemia
what are the lab signs of ACD?
- higher levels of CRP
- higher ESR
- acute phase response
- inc. in ferritin, factor VIII, fibrinogen and IG
what are the conditions associated with ACD?
- chronic infections e.g. TB/HIV
- chronic inflammation
- malignancy
What is the pathogenesis of ACD?
- mostly due to cytokine release e.g. TNF alpha, IL
- cytokines prevent usual flow of iron from duodenum to red cell (block utilisation by red cells)
- cytokines stop EPO inc., stop iron flow out of cells, inc. production of ferritin, inc. death of RBCs
what is the major cause and minor causes of iron deficiency?
Major: bleeding e.g. menstrual or GI Minor: - inc. use (growth/pregnancy) - dietary def (e.g. vege) - malabsorption (e.g. coeliac)
when are full investigations into iron def carried out?
- male
- woman over 40, post menopausal women, women with scanty menstrual loss
what is in a full GI investigation?
- upper GI endoscopy
- duodenal biopsy and colonoscopy
when do you do nothing?
- menstruating woman <40 with heavy period
- multiple pregnancies and no GI symptoms
- urinary blood loss
- antibodies for coeliac disease
describe the levels of Hb, MCV, serum iron, ferritin, transferrin and transferrin saturation in people with thalassemia trait?
Hb: low MCV: low Serum iron: normal Ferritin: normal transferrin: normal transferrin saturation: normal
describe the levels of Hb, MCV, serum iron, ferritin, transferrin and transferrin saturation in people with classic ACD
Hb: low MCV: low or normal serum iron: low ferritin: high or N transferrin: normal or low transferrin saturation: normal
describe the levels of Hb, MCV, serum iron, ferritin, transferrin and transferrin saturation in people with classic iron def
Hb: low MCV: low Serum iron: low ferritin: low transferrin: high transferrin saturation: low
