IRON and IRON DEFICIENCY ANAEMIA Flashcards
(36 cards)
To carry out its functions (oxygen and electron transport) iron must be kept in what state?
Fe 2+ ferrous form
Why is its conversion to Fe2+ dangerous?
It can cause inflammation and oxidative stress by the formation of free radicals.
Iron is actively excreted T/F?
F. No mechanism for active excretion of iron.
Where is the majority of the bodies iron found?
Bound to haem
What is the
A) reccomended daily intake of iron
B) amount that should be absorbed
C) normal amount stored?
A)10-20mg
B)1mg
C) 4mg
Where is iron absorbed from?
DUODENUM
Iron is taken in by the diet in ferric (Fe3+) form what converts it to Fe2+ form for absorption?
Vitamin C enzyme on enterocyte apical surface
Once absorbed into enetrocyte Fe2+ can either
A) oxidse to ferric form and be stored bound to ___
B) EXIT the cell via ____ to be transported round the body?
A) ferritin
B) Ferroportin
Upon exiting the enterocyte (via ferroportin) Fe2+ is oxides to ferric form and bound to which protein?
Transferrin. carrier protein for iron.
MEasuring transferrin saturation is useful to get an idea of?
How much iron is being transported/ iron supply
On iron studies what does total iron binding capacity (TIBC) reflect?
Availability of iron binding sites on transferrin the blood.
What is the main liver protein which controls iron absorption?
HEPCIDIN
How does hepcidin decrease plasma iron concentration in response to increased iron load and inflammation?
It down regulates ferroportin (channel responsible for exit of iron from cells) => inhibiting release of iron into the circulation.
Iron bound to transferrin mainly gets taken to?
Tissues with transferrin receptors:
BONE MARROW
LIVER
Macrophages
Iron deficiency anaemia will have HIGH/LOW TIBC?
HIGH. Stores of iron = low, body compensates by increasing transferrin => increases bodys ability to bind iron.
Causes of iron deficiency anaemia?
Dietary
Blood loss
Malabsorption
Why must all men with unexplained iron deficiency get GI investigations (endoscopy +/- colonoscopy)?
Iron deficiency is uncommon in men. (they have reduced iron requirements) therefore cause is almost always PATHOLOGICAL (GI bleed, malabsoprtion, malignancy)
Ferritin is an indirect measure of storage iron. Why is it HIGH in anaemia of chronic disease?
Ferritin is also an acute pahse protein => will rise with infection, malignancy etc.
Which GI condition should all those presenting with iron deficiency anaemia be screened for?
Coeliac. Blood test ttg.
1st line treatment for iron deficiency?
200mg Ferrous Sulphate or fumerate TDS
Side effects of iron supplements?
Nasea, constipation, diarrhoea, black stool
If there is no response to iron supplementation in ____ then further investigations (GI) are done.
3 months. (120 day life span of RBC => 120 days to see repletion)
Other than no response to treatment and being male with unexplained iron deficiency, what other circumstances grant immediate GI investigation for iron deficiency?
Women with unexplained iron deficiency and NOT menstrating. (menorrhagia = common cause)
Iron deficiency with either dyspepsia (may be stomach ulcer) or rectal bleeding (suggests CRC)
How does anaemia of chronic disease affect hepcidin levels?
Release of cytokines STIMULATES hepcidin => blockage of Fe++ entering circulation and plasma conc. of iron REDUCES. Anaemia of chronic disease presents as microcytic hypochromic anaemia.
