Lecture 9 - Iron Deficiency Flashcards
1
Q
Hemoglobin synthesis requries
A
- heam synthesis
- globin synthesis
- iron
2
Q
Red cell production requires
A
- erythropoietin
- vitamin B12 and folic acid
3
Q
Iron deficiency causes
A
- increased iron requirements: growth (Childhood or pregnancy) - treated with erythropoiesis stimulating agents
- limited external supply: poor intake, diet with deficit in bioavailable iron and or ascorbic acid, malabsorption (gastric resection, H pylori infection, chrons, coeliac disease, drug interference)
- blood loss: venesection, hemmorhage
4
Q
Iron rich food and iron poor food
A
- iron rich: liver, red meat, peas and beans, fish and poultry, green leafy veggies
- iron rich but poorly absorbed: spinach (because contains high levels of oxalates which removes iron from body)
- iron poor: fruit, milk, yoghurt, cheese, rice
5
Q
Decreased absorption dietary facrtors
A
- phytates
- oxalates
- phosphates
6
Q
Dietary factors that increase iron absorption
A
- hydroquinone
- ascorbate
- lactate
- pyruvate
- succinate
- fructorse
- cysteine
- sorbitol
7
Q
Clinical presentation of iron deficiency
A
- no signs or symptoms
- manifestations common to all anemias
- signs higly specific of iron deficiency: pagophagia, koilonychia, blue sclera
- clinical manifestations independent of anemia glossitis, angular sotmatitis, postcricoid esophageal web or structure, gastric atrophy, impaired immunity and resistance to infection, behavioral and neuropsychological abnormalities
8
Q
Iron studies
A
- serum ferritin assay: small quantity of ferritin in human serum reflects body iron stores. Most clinical laboratories use an immunoassay system
- estimation of serum iron concentration: iron is carried int he plasma bound to the protein transferrin. Serum iron concentration alone provides little useful clinical information
9
Q
Iron binding capacity
A
- in the plasma, iron is bound to transferrin and total iron-binding capacity (TIBC) is a measure of this protein
- excess iron as ferric chloride is added to serum
- iron that does not bind to transferrin is removed with excess magnesium carbonate
- iron concentration of the iron-saturated serum is measured
- although a raised TIBC is charactrerisitc of iron deficiency anemia, the TIBC is usually used to calculate the transferrin saturation
- additional iron-binding capacity of transferrin is known as the unsaturated iron bunding capacity (UIBC)
10
Q
Transferrin saturation
A
- the ration of the serum iron concentration and the TIBC, expressed as a percentage
- most valuable use of transferrin saturation is for the detction of genetic heamochromatosis
11
Q
Serum transferrin receptor
A
- almnost all cells in the body obtain iron from the plasma protein transferrin
- transferrin receptors detectable in the plasma by immunoassay
- no agreement about the source of transferrin receptor as standard or as an antigen for the raising of antibodies
- circulating transferrin receptor levels increase not only in patients with simple iron deficiency but also in patients with the anemia of chronic disease who lack sustainable iron in the bone marrow
- sTFR has not proved to be superior to serum ferritin for detecting iron deficiency
12
Q
Iron studies summary
A
- Ferritin: decreases in iron deficiency and increases in chronic disease and iron overload
- serum ion: decreases in iron deficiency and increases in haemochromatosis
- transferrin: increases in iron deficiency, saturation decreases in iron deficiencu and chronic disease, and saturation icnreases in overload
- total iron binding capacity: measures available iron binding sites on transferrin, increaes in iron deficiency
13
Q
Ferritin - most useful indirect estimate of body iron stores
A
- in the absence of inflammation, ferritin level is
14
Q
True iron deficiency
A
Ferritin
15
Q
False iron deficiency
A
- ferritin > 100 ng/ml and transferrin saturation
