Continuity Clinic Iron Deficiency Anemia

Continuity Clinic Objectives Understand the prevalence and epidemiology of iron deficiency Describe the consequences of iron deficiency Formulate a diagnostic and therapeutic plan to manage iron deficiency

Continuity Clinic Background Most common nutritional deficiency in the world –In US caused by insufficient dietary iron –Infants and toddlers susceptible because of rapid growth and increased demand for iron Most common: 1-3 years of age –9% of children under 3 years of age have evidence of iron deficiency of which 1/3 are anemic

Continuity Clinic Background Stages: 1)Iron depletion = earliest stage of diminishing iron stores in the setting of insufficient iron supply 2)Iron deficiency = no anemia, develops as iron stores are depleted further and begin to impair hemoglobin synthesis 3)Iron deficiency anemia = supply is insufficient to maintain normal levels of hemoglobin

Continuity Clinic Background Anemia of lower prevalence today and is limited in its use to screen for iron deficiency High risk of anemia: –Premature, IUGR infants –Breastfed infants greater than 6 months not receiving iron supplements –Low socioeconomic status

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Iron Requirements & Factors Contributing to Deficiency

Continuity Clinic Iron Storage and Metabolism Functional Iron –Heme iron for hemoglobin and myoglobin –Enzymatic processes involved in respiration, dopamine synthesis, CNS myelination Stored Iron –Ferritin

Continuity Clinic Iron Storage and Metabolism 80% of iron stores accumulated in 3rd trimester – stores should last for 4-6 months (requirement 1 mg/kg/day) Preterm infants – = 2mg/kg/day –<1500 = 4 mg/kg/day

Continuity Clinic Iron Intake and Absorption Daily recommendations exceed actual needs – WHY? –The digestive process can alter the amount of iron actually absorbed! –Variables include: 1) amount of iron in body, 2) rate of RBC production, 3) amount and type of iron in diet, 4) presence of absorption enhancers and inhibitors in diet

Continuity Clinic Iron Intake and Absorption Low iron/high RBC production = increase iron absorption Heme iron in meat, poultry, and fish = 2-3 times more absorbable than non-heme in plant based foods Absorption –Enhance = ascorbic acid (vitamin C) –Inhibitors = bran, fiber, calcium, tannins, polyphenols in some vegetables

Continuity Clinic Iron Intake and Absorption Breast milk and cow milk 0.5 mg/L of iron –50% of iron from breast milk is absorbed –10% of cow milk absorbed 5% of iron in fortified formulas absorbed, but formulas have much higher concentrations in range of mg/L After 6 months of age – supplement breastfed infants with 1-2 mg/kg/day of iron!

Continuity Clinic Iron Intake and Absorption Others at risk: –Toddlers drinking more than 24 oz/day of cow milk  low iron produce and high satiation value in place of iron-rich foods –Infants introduced to whole milk prior to 12 months of age  low bioavailability of iron and association with occult GI bleeding

Continuity Clinic Clinical Impact of Deficiency

Continuity Clinic Clinical Manifestations and Complications of Iron Deficiency Usually Asymptomatic Anemia –Pallor, fatigue, tachycardia, blue sclera, splenomegaly, anorexia, pica (due to increased lead absorption) BEHAVIORAL AND DEVELOPMENTAL –Lower test scores of mental and motor development among infants

Continuity Clinic Diagnosis

Continuity Clinic Diagnosis of Anemia Don’t forget your history – Are they at risk? Remember that anemia is the end result of iron deficiency! Start with hematologic (reflect RBC status) before biochemical markers (reflect iron metabolism, more sensitive) as they are cheaper

Continuity Clinic Diagnostic Testing Iron DepletionIron Deficiency w/o Anemia Iron Deficiency Anemia FerritinNormal/Low*Low Transferrin saturation NormalHigh Erythrocyte protoporphyrin NormalHigh MCVNormal Low (microcytic) RDWNormalHigh HemoglobinNormal Low

Continuity Clinic Review of the Tests Hemoglobin – measures the concentration of oxygen carrying protein MCV – average volume of RBC’s RDW – index of variation of RBC size Ferritin – storage compound for iron Erythrocyte Protoporphyrin – immediate precursor of hemoglobin Transferrin saturation – proportion of occupied iron binding sites and reflects iron transport Hematologic Biochemical

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Diagnosis In most cases, simple hematologic tests associated with an appropriate history and a trial of iron therapy that demonstrates an increase in hemoglobin by 1.0g/dL or more in 1 month are sufficient to make the diagnosis of iron deficiency anemia. –Capillary blood samples should be confirmed by venous puncture If there is doubt – use the biochemical makers to help with the diagnosis!

Continuity Clinic Diagnosis Mentzer index – used to differentiate iron deficiency anemia from beta thalasemia; high sensitivity but low specificity MI = MCV/RBC count MI < 13  likely thalasemia MI > 13  likely iron deficiency anemia

Continuity Clinic Treatment

Continuity Clinic Treatment Start empiric treatment with oral elemental iron at 3-6 mg/kg/day and retest after 4 weeks of therapy –Increase of Hgb by 1g/dL or 3% rise in hct confirms the diagnosis of iron deficiency –Continue therapy for 2 months and recheck –Discontinue if normal and recheck in 6 months

Continuity Clinic Treatment If no response to therapy: –Confirm compliance –Intercurrent ilness? –Stool for occult blood –Check MCV, RDW, Serum Ferritin

Continuity Clinic Screening Universal screening for populations at risk –9-12 months –15-18 months Selective screening based on individual risk

Continuity Clinic Prevention Breastfed –Supplement all breastfed babies by 4-6 months of age – 1 mg/kg/day –Preterm infants – 2 mg/kg/day –Only use iron fortified formula for supplementing ( mg/dL) Formula –Preterm – 1mg/kg/day iron in addition to preterm formula –Only use iron fortified formula

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