Lecture 9 - Iron Deficiency Flashcards Preview

Block 4 - Heamatology > Lecture 9 - Iron Deficiency > Flashcards

Flashcards in Lecture 9 - Iron Deficiency Deck (24)
1

Hemoglobin synthesis requries

- heam synthesis
- globin synthesis
- iron

2

Red cell production requires

- erythropoietin
- vitamin B12 and folic acid

3

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

4

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

5

Decreased absorption dietary facrtors

- phytates
- oxalates
- phosphates

6

Dietary factors that increase iron absorption

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

7

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

8

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

9

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)

10

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

11

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

12

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

13

Ferritin - most useful indirect estimate of body iron stores

- in the absence of inflammation, ferritin level is

14

True iron deficiency

Ferritin

15

False iron deficiency

- ferritin > 100 ng/ml and transferrin saturation

16

Iron deficiency anemia

- low Hb
- transferrin sat

17

Iron deficiency anemia without microcytosis:

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

18

Blood film- iron deficiency

- morphological changed qwhen Hb

19

Severe iron deficiency

Leucopenia and thrombocytopenia in 10%
- occasionally hypersegmented neutrophils


- endemic hookworms: eosinophilia

20

DDx: thalassemia

- low MCV despite normal Hb

21

DDx: anemia of chronic disease

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

22

DDx: iron deficiency anemia

- anisochromasia
- pencil cells
- low MCHC

23

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

24

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)