The Journal of the Arkansas Medical Society Med Journal Aug 2019 Final 2 | Page 16

Table 1: Common laboratory findings in iron deficiency anemia, thalassemia and
anemia of chronic disease. 4,6
Lab Values IDA
Hgb Anemia is defined as two standard deviations below the mean of the
population of same age and gender.
RBC count Decreased
Increased
Decreased
MCV Decreased
Decreased
Decreased
/=14
Anemia of Chronic Disease
RDW Increased Normal/increased Normal
Ferritin Decreased Normal Increased
TIBC Increased Normal Normal/Decreased
(non-fasting) serum iron. Hypoferritinemia is diag-
nostic for IDA if the value is less than 12 ng/mL
in children ages 1 to 5 years or less than 15 ng/
mL in children older than 5 years of age. However,
since ferritin is an acute-phase reactant, it may
be elevated and thus not reflective of tissue iron
stores during periods of inflammation or illness. 8
Measurement of serum iron is not a reliable in-
dicator of iron status as there is natural diurnal
variation, and the value may be elevated after iron
intake despite depletion of body iron stores. 5
If iron studies are unremarkable, other
causes of microcytic anemia in children need
to be considered including thalassemia, anemia
of chronic disease, and lead poisoning. Table 1
compares the laboratory findings amongst these
etiologies.
Treatment
Once IDA is diagnosed, oral iron therapy
should be initiated. A packed red blood cell
transfusion is only recommended if anemia is
severe and the child demonstrates clinical signs
of distress: tachycardia, chest pain, shortness of
breath, dizziness, poor feeding, or poor growth.
If required, pRBCs must be transfused slowly to
prevent overload and heart failure. In addition
to transfusion, oral iron supplementation is re-
quired since the iron in the donor red cells is not
available for red cell production. 3
The standard dosing recommendation for
oral iron in IDA varies widely from 3 to 6 mg/kg/
day of elemental iron divided in one to three daily
doses. 7 There are multiple oral iron preparations
available, and the amount of elemental iron
varies by formulation. For example, in ferrous
sulfate, elemental iron comprises 20% of the
total dose, so 15 to 30 mg/kg/day of ferrous
sulfate is recommended. A recent, randomized
clinical study suggests that ferrous sulfate
results in a greater increase in both hemoglobin
and iron indices when compared to another
formulation, iron polysaccharide complex. 9
In another study comparing a single daily
dose versus three divided daily doses, both regi-
mens showed a comparable increase in hemo-
globin and ferritin. 10 Several trials have suggest-
ed that lower, once-daily doses may be as effec-
tive as high doses since the absorptive capacity
of the duodenum appears to be saturable. 5,7 For
children who poorly tolerate oral iron, once-daily
dosing given every other day can also provide
good effect. 7 For moderate-to-severe IDA, we
typically give ferrous sulfate at 20-30 mg/kg/day
divided twice daily and capping at one 325 mg
tablet two or three times daily in larger children
and adolescents. Whichever iron formulation is
chosen, it is critical that the prescriber be aware
of the proportion of elemental iron present in the
chosen iron preparation and dose appropriately.
In our experience, many children referred for he-
matology consultation of poor response to iron
therapy have been under-dosed.
Poor compliance with treatment is com-
mon due to dosing frequency, grey discoloration
of teeth, constipation, nausea, and poor taste. 4
Families should be counseled to wipe the teeth
after administration to prevent discoloration and
start a stool softener, if needed, for constipa-
tion. The iron supplement should be given one
to two hours before or after meals with water
or juice. It is important to avoid milk products
with iron administration since this can decrease
Table 2: Etiologies of poor response to oral iron treatment. 8
Common Etiologies
of Treatment Failure
with Oral Iron: Recommendations:
Inadequate Dosing Prescribe 3-6 mg/kg/day of elemental iron (e.g. 15-30 mg/kg/day of
ferrous sulfate).
Inadequate Duration of
Treatment Treat for a minimum of 12 weeks or until ferritin and CBC normalize.
Improper Administration Administer on an empty stomach with water or juice. Do not give with
milk. Avoid antacids, H2 blockers, and PPIs if possible.
Poor Compliance Prescribe once-daily dosing. Prescribe slow-release formulations.
Give at bedtime to help minimize stomach upset. Counsel on and treat
constipation.
Poor Diet Educate on proper nutrition. Encourage less than 20 ounces of cow’s
milk daily. Increase iron-rich foods.
Ongoing Blood Loss or
Malabsorption Evaluate for chronic bleeding or malabsorption (e.g. menorrhagia or
metrorrhagia in females, inflammatory bowel disease, Celiac disease,
high stomach pH)
Incorrect Diagnosis Other microcytic anemias to consider include thalassemia, anemia of
chronic disease, sideroblastic anemia, lead poisoning.
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