Lecture 9 - Iron Deficiency Flashcards Preview

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Flashcards in Lecture 9 - Iron Deficiency Deck (24)
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Hemoglobin synthesis requries

- heam synthesis
- globin synthesis
- iron


Red cell production requires

- erythropoietin
- vitamin B12 and folic acid


Iron deficiency causes

- 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


Iron rich food and iron poor food

- 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


Decreased absorption dietary facrtors

- phytates
- oxalates
- phosphates


Dietary factors that increase iron absorption

- hydroquinone
- ascorbate
- lactate
- pyruvate
- succinate
- fructorse
- cysteine
- sorbitol


Clinical presentation of iron deficiency

- 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


Iron studies

- 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


Iron binding capacity

- 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)


Transferrin saturation

- 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


Serum transferrin receptor

- 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


Iron studies summary

- 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


Ferritin - most useful indirect estimate of body iron stores

- in the absence of inflammation, ferritin level is


True iron deficiency



False iron deficiency

- ferritin > 100 ng/ml and transferrin saturation


Iron deficiency anemia

- low Hb
- transferrin sat


Iron deficiency anemia without microcytosis:

- coexisting vit B12 or folate deficiency
- post bleeding reticolocytosis
- oral iron treatment
- alcohol intake


Blood film- iron deficiency

- morphological changed qwhen Hb


Severe iron deficiency

Leucopenia and thrombocytopenia in 10%
- occasionally hypersegmented neutrophils

- endemic hookworms: eosinophilia


DDx: thalassemia

- low MCV despite normal Hb


DDx: anemia of chronic disease

- increased rouleaux formation: red cell stacking
- increased background staining: immunoglobulin


DDx: iron deficiency anemia

- anisochromasia
- pencil cells
- low MCHC


Therapy for iron deficiency

- oral iron
- ferrous salts. Co administration with Vit C may enhance absorption
- non-absorbed iron salts: ROS, hypochlorous acid, superocid and peroxyde. But these can cause nausea, flatulence, diarrhoea or constipation, balck or tarry stools


Parenteral iron indication

- intolerance to oral iron
- contrainidcation to oral iron
- inadequate response to oral iron

- 5-fold erythropoietic response to significant iron deficiency anemia
- Hb starts to rise after a few days, iron stores are replete
- percentage of repsonding patients is higher
- each iron product is taken up into the reticuloendothelial system (RES)