Haematology II Iron deficinecy Anaemia

Haematology IIIron deficinecy Anaemia

BMLS Year II2010

02/03/100

Iron Deficiency AnaemiaQuick overview of Iron metabolismWhere is Iron found in the body? Functional - 70%• Haemoglobin• Myoglobin• Enzymes

Storage - 30% - liver, spleen, BM• Ferritin• Haemosiderin

Transport - 0.1%• Transferrin

Iron Deficiency Anaemia

Haemoglobin

HAEM

Iron cycle

Iron Absorption

Food iron• Meat, vegetables, eggs, dairy foods• Haem–protein, ferric hydroxides, ferric-

protein complexes• Duodenum• Daily average Western diet 10-15 mg iron,• 5-10% absorbed

Factors Affecting Absorption

• Form of iron - Haemiron, inorganic iron• Valency – Fe 2+, Fe 3+• pH - acid (HCL, vitamin C), alkaline• Food components – sugars, phytates, tea• Iron stores• ferroportin • Erythropoiesis• nPregnancy• Favour or reduce absorption

Transport and Uptake of Iron

• Transferrin• Glycoprotein, transports iron• Synthesised by liver• Binds up to 2 Fe 3+ atoms• Transferrin receptors• Located on cell surface and required for

uptake of iron• Higher affinity for diferric transferrin than

monoferric transferrin

Iron Deficiency Anaemia

Develops when the intake of Iron is inadequate to meet a standard level of demand, when the need for iron expands, or when there is chronic loss of Hb from the body

Iron Deficiency Anaemia

Causes:Inadequate Intake - dietary inadequacyIncreased Need – Rapid growth infancy,

childhood and adolescence, pregnancy Chronic Blood loss- slow haemorrhage or

haemolysis, GI bleeding, kidney stones or tumors, PNH

Iron Deficiency Anaemia• Iron deficiency is the commonest cause of

anaemia worldwide• is frequently seen in general practice. • The anaemia of iron deficiency is caused by

defective synthesis of haemoglobin, resulting in red cells that are smaller than normal

(microcytic)• and contain reduced amounts of

haemoglobin (hypochromic).

Iron Deficiency AnaemiaPathogenesisFe deficiency anaemia develops slowly.Iron is distribute among three

compartments:1. The storage compartment, principally as

ferritin in the BM,macrophages and liver cells2.The transport compartment of serum

transferrin and3.The functional compartment of Hb,

myoglobin and cytochromes

Iron Deficiency AnaemiaStage IIs characterized by a progressive loss of

storage ironThe body’s reserves of iron is sufficient to

maintain the transport and functional compartments through this phase – RBC development is normal

No evidence of Fe deficiency in PB picturePatient experiences no symptoms of anaemiaFerritin level will be low

Iron Deficiency AnaemiaStage 2 Is define by the exhaustion of the storage pool of iron. For a time, RBC production continues as normal, relying

on the iron available in the transport compartment. Anaemia is still not evident, although individual’s Hb

may begin dropping Other iron depend tissues, such as muscle may begin to

be affected – the symptoms may be nonspecific. Ferritin levels and serum iron are still low TIBC increases Prussian blue stain of marroe in stage 2 would show no

essentially stored iron and iron deficient erythorpoisis would be evident

Iron Deficiency AnaemiaStage 3 Fe deficiency is frank anaemia The Hb and Hct are relatively low Thoroughly depleted storage iron and diminished

transport iron RBCs are not developed normally. The number of cells divisions /precursor increases

because Hb accumulation in developing cells is slowed – allowing more time of divisions

The result is first smaller cells with adequate Hb conc.

Microcytic and hypochromic

Iron Deficiency Anaemia

Stage 3… cont’dFerritin levels - very lowFree erythrocyte protoporphrin and

trasferrin receptors -increaseOther iron studies are abnormal

Iron Deficiency AnaemiaDiagnosis: Clinical features• The symptoms accompanying iron deficiency

depend on how rapidly the anaemia develops.

• In cases of chronic, slow blood loss, the body adapts to the increasing anaemia, and

• Patients can often tolerate extremely low concentrations of haemoglobin—for example, 7.0 g/dL

Iron Deficiency AnaemiaClinical featuresFatigue and weaknessPallorInflamed cracks at the corners of the mouth

[angular chelosis]Koilonychia [spooning of the fingernails]Craving for nonfood items

Iron Deficiency Anaemia

Iron Deficiency AnaemiaLaboratory FindingsBlood Film:• Microcytic hypochromic anaemia, aniso/poikilo,

target cells, ‘pencil’ cells• Raised PLT countBone marrowNot needed for diagnosis.• Erythroblasts show ragged irregular cytoplasm• Absence of iron from stores and erythroblasts• Serum ferritin reduced• Serum iron low• Transferrin raised• TIBC raised• Serum soluble transferrin receptors increased

Iron Deficiency Anaemia

Iron Deficiency Anaemia

Iron Deficiency AnaemiaOther investigations• History [blood loss, diet, malabsorption]• Test for parasites• Urine haemosiderin• Hb electrophoresis and/or globin gene DNA

analysis to exclude thalassaemia trait or other Hb defects

Iron Deficiency Anaemia

Iron Deficiency AnaemiaTreatment• Oral iron – ferrous sulphate• Prophylactic oral iron often combined with

folic acid is given in pregnancy.• Intramuscular iron is used in patient with

malabsorption, this who are not able to take oral iron.

- renal dialysis pts receiving erythropoietin therapy

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Text Book: Hoffbrand, Pettit & Moss. Pp 31-38