Lecture 9 - Iron Deficiency

Question 1

Hemoglobin synthesis requries

Answer 1

• heam synthesis
• globin synthesis
• iron

Question 2

Red cell production requires

Answer 2

• erythropoietin

- vitamin B12 and folic acid

Question 3

Iron deficiency causes

Answer 3

• 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

Question 4

Iron rich food and iron poor food

Answer 4

• 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

Question 5

Decreased absorption dietary facrtors

Answer 5

• phytates
• oxalates
• phosphates

Question 6

Dietary factors that increase iron absorption

Answer 6

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

Question 7

Clinical presentation of iron deficiency

Answer 7

• 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

Question 8

Iron studies

Answer 8

• 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

Question 9

Iron binding capacity

Answer 9

• 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)

Question 10

Transferrin saturation

Answer 10

• 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

Question 11

Serum transferrin receptor

Answer 11

• 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

Question 12

Iron studies summary

Answer 12

• 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

Question 13

Ferritin - most useful indirect estimate of body iron stores

Answer 13

• in the absence of inflammation, ferritin level is

Question 14

True iron deficiency

Answer 14

Ferritin

Question 15

False iron deficiency

Answer 15

• ferritin > 100 ng/ml and transferrin saturation

Question 16

Iron deficiency anemia

Answer 16

• low Hb

- transferrin sat

Question 17

Iron deficiency anemia without microcytosis:

Answer 17

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

Question 18

Blood film- iron deficiency

Answer 18

• morphological changed qwhen Hb

Question 19

Severe iron deficiency

Answer 19

Leucopenia and thrombocytopenia in 10%
- occasionally hypersegmented neutrophils

• endemic hookworms: eosinophilia

Question 20

DDx: thalassemia

Answer 20

• low MCV despite normal Hb

Question 21

DDx: anemia of chronic disease

Answer 21

• increased rouleaux formation: red cell stacking

- increased background staining: immunoglobulin

Question 22

DDx: iron deficiency anemia

Answer 22

• anisochromasia
• pencil cells
• low MCHC

Question 23

Therapy for iron deficiency

Answer 23

• 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

Question 24

Parenteral iron indication

Answer 24

• 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)