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 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..
Top Related