Iron deficiency anemia

Introduction One of the most prevalent forms of malnutrition

Globally 50% of anemia is attributable to iron deficiency

Iron metabolismCritical element

Various functions

Carry O2 as part of HemoglobinMyoglobinCytochrome system in mitochondria

Free iron is toxic

Body iron distribution

Iron content in mgADULT MALE ,8O KgADULT FEMALE,60 kgHemoglobin 25001700Myoglobin 500300Transferrin iron33Iron stores600-10000-300

Iron cycleRegulated by absorption

Iron losses are unregulatedGi loss and menstrual cycle loss

Absortion in duodenum

Iron absorptionDietary Fe in ferric form

Reduced to Fe2+ by ferric reductase

Transported through DMT1

Inside the cell stored as ferritin

Transported across BL membrane through ferroportin

Ferroportin is negatively regulated by hepcidin

Hephaestin is a ferroxidase which oxidises Fe2+ to Fe3+

Fe3+ binds to transferrin

Transferrin has 2 binding sites

Normally transferrin is 35% saturated with Fe

Diferric transferrin has high affinity to transferrin receptors in marrow erythroid cells

The complex is internalised via clathrin coated pits and in the endosome Fe is released

Fe utilized for heme synthesis

Remaining bind to apoferritin to form ferritin

Transferrin receptors are present in liver parenchymal cells also.

Senescent RBCs phagocytosed by RE cells,Fe is released and bind to transferrin.

Factors affecting Fe absorptionVit CGastric HClHeme Fe (redmeat)> liver Fe> egg Fe> veg Fe

Phytates PhosphatesTannates

Fe deficiency hepcidin lowErythroid hyperplasia

Normal iron parameters

Seum ferritin 50-200 ug/lTIBC300-360 ug/dlSerum Fe50-150 ug/dlTransferrin saturation30-50%Marrow sideroblasts40-60%RBC protoporphyrin30-50 ug/dl

Averae Fe intake is 15mg/d with 6% absorption in males

11mg/d with 12% absorption in femles

Iron deficiency anemiaSTAGES OF IRON DEFICIENCY

Negative iron balanceIron deficient erythropoeisisIron deficiency anemia

Negative iron balanceDemand exceeds capacity to absorb

Physiologic increased demand,blood loss,inadequate dietary intake

Moblization of Fe from RE storage sites

Serum ferritin decreases

Iron deficient erythropoiesisSerum ferritin

Iron def anemiaHemoglobin and hematocrit begin to fall

T .sat is 10-15%

Causes of iron deficiencyINCREASED DEMAND FOR IRON

Rapid growth in infancy or adolescencePregnancyErythropoietin therapy

INCREASED IRON LOSS

Chronic blood loss esp GI blood lossMenorrhagiaAcute blood lossPhlebotomy

DECREASED IRON INTAKE OR ABSORPTION

Inadequate dietMalabsorption syndromesPost gastrecomyAcute or chronic nflammation

Clinical featuresFatigueExercise intoleranceDyspnea ,palpitation,syncope

Pica

Symptoms related to etiology

o/ePallor

Glossitis

Cheilitis

Platynychia,longitudinal ridging,koilonychia

Lab investigationsHEMOGRAM

Anemia

Low MCV,MCH

RDW high

Platelet count elevated

Peripheral smearMicrocytic hypochromic anemia with anisopoikilocytosis

Iron studiesLow serum ferritinLow serum ironIncreased TIBC Low T sat ( seum iron* 100/TIBC )Transferrin receptor protein levels elevatedIncreased redcell protoporphyrin

Differential diagnosisBeta thalssemia traitAnemia of chronic diseaseMDS

TREATMENTRed cell transfusion

Oral iron therapy 200-300mg/d in empty stomach in divided dosesFerrous sulfate,fumarate,gluconate,polysaccharide iron6-12 months after correction of anemia

Side effectsAbdominal pain,nausea,vomiting,constipation

Response to treatmentReticulocyte increasewithin 4-7 d and peaks at 1-1.5 wks

Pareteral ironIndications

Oral iron intoleranceWhose iron needs are relatively acuteWho need iron on an ongoing basis

Iron dextran,sodium ferric gluconate, iron sucrose

2 modes

To administer total dose of iron together

To give small repeated doses of iron over a period

Amount of iron needed

Body weight (kg)* 2.3* (15-patients hemoglobin) + 500 -1000 mg

Side effects

Anaphylaxis,arthralgias,skin rash,low grade fever

Take home messagePreventable cause of anemia

IDA in elderly ,rule out GI malignancies

Mild to mod iron deficiency is hypoproliferative anemia while in severe iron deficiency there will be erythroid hyperplasia..