iron deficiency anemia

Question 1

When does the Hgb nadir occur in newborn infants?

Answer 1

6-8 weeks of life (physiologic anemia of infancy)

Question 2

What causes physiologic anemia of infancy?

Answer 2

1. RBC production temporarily stops with onset of respiration at birth
2. EPO has a shorter half-life and larger Vd in newborns
3. Fetal RBCs have a shorter lifespan

Question 3

How to calculate lower limit of normal Hgb level in children 12 months to 6 years?

Answer 3

11 + (0.1 x age in years) = lower limit of normal for Hgb

Question 4

From 6-12 years, the lower limit of normal Hgb is?

Answer 4

11.5 g/dL

Question 5

From 12-18 years, the lower limit of normal Hgb is?

Answer 5

Females: 12 g/dL
Males: 13 g/dL

Question 6

Lab workup for anemia found on capillary (fingerstick) Hgb?

Answer 6

CBC, retic, peripheral blood smear (preferably via venipuncture)

Question 7

How does RDW differ in iron deficiency anemia versus thalassemia?

Answer 7

HIGH RDW in IDA
Normal in thal minor

Question 8

What is Mentzer index?

Answer 8

MCV / RBC count

Used to differentiate IDA from thal minor

Question 9

Mentzer index >13.5 suggests?

Answer 9

Iron deficiency anemia (low MCV and low # RBCs, so ratio is higher)

Question 10

Mentzer index <11.5 suggests?

Answer 10

Thalassemia minor (low MCV and normal # RBCs, so low ratio)

Question 11

What are the three stages of iron deficiency?

Answer 11

1. Depletion of iron stores (decreased ferritin)
2. Decreased Hgb
3. Decreased MCV

May also see mild-moderate thrombocytosis

Question 12

During the first year of life, infants require how much iron?

Answer 12

0.8 mg per day

Question 13

When should iron supplementation start for infants?

Answer 13

After 6 months, supplement with iron-rich foods such as fortified infant cereals

Applies to breast-fed and formula-fed infants

Question 14

When to screen for anemia via Hgb level?

Answer 14

12 months
24 months

Question 15

What is reticulocyte hemoglobin concentration (CHr) used for?

Answer 15

Inflammation-independent measure of iron stores

Question 16

What to do if Hgb <11 or high concern for IDA?

Answer 16

Options:
- Treat empirically and repeat Hgb in 1 month (if stable)
- Measure ferritin +/- CRP
- Measure CHr

Question 17

What are dietary risk factors for IDA in toddlers?

Answer 17

Early introduction of cow’s milk (before 1 year)
Drinking >24 oz/day of cow’s milk

Question 18

Why is cow’s milk associated with IDA?

Answer 18

Low in iron
Interferes with iron absorption
May cause occult GI bleeding

Question 19

Milk hypersensitivity with pulmonary hemosiderosis is called ____.

Answer 19

Heiner Syndrome (rare)

Question 20

What are examples of iron-rich foods?

Answer 20

Meat, fish, legumes, leafy green vegetables
Fortified bread, noodles, and cereals

Question 21

What enhances iron absorption?

Answer 21

Vitamin C and an acidic environment
Giving Fe every other day or in lower doses if possible

Question 22

What is the preferred treatment for IDA in toddlers?

Answer 22

Ferrous sulfate (note: these contain only 20% elemental iron)
3-6 mg/kg of elemental iron divided twice daily

Question 23

Where is iron absorbed?

Answer 23

Duodenum

Question 24

Side effects of iron treatment?

Answer 24

Constipation, dark stools, dental staining, nausea, epigastric pain

Take after meals to decrease GI upset

Question 25

What can be used as an alternative to ferrous sulfate if medication adherence is a concern?

Answer 25

Iron polysaccharide complex (e.g., NovaFerrum drops) Less effective than ferrous sulfate but better than nothing

Question 26

How to determine duration of therapy for iron treatment?

Answer 26

Check CBC in 1 month. Should increase by 1 g/dl of Hb if it is IDA. If so, continue iron therapy for 1 month after normalization of Hgb level to fully replete iron stores.

Question 27

What are serious complications of anemia?

Answer 27

Tachycardia Cardiac dilatation Possibly cognitive achievement if early in life

Question 28

What diagnoses should you consider in a child whose microcytic anemia does not respond to iron therapy?

Answer 28

Hemoglobinopathies Lead poisoning

Question 29

What is the role of transferrin?

Answer 29

Binds to Fe and allows it to be absorbed in SI Fe is then released and incorporated into heme

Question 30

What is the role of ferritin?

Answer 30

Stores iron outside of Hb-producing cells

Question 31

Where is iron stored?

Answer 31

60-70% of total iron is in hemoglobin Small amount in heme, other enzymes, myoglobin Rest stored as ferritin (in liver, bone marrow, spleen, and muscle)

Question 32

What is the role of reticulocyte count?

Answer 32

Evaluates RBC production in response to anemia

Question 33

What marker is highly specific for IDA?

Answer 33

Serum ferritin (storage form of iron, NOT sensitive though b/c it is an acute phase reactant)

Question 34

What is the role of TIBC?

Answer 34

Indirectly measures transferrin, which is a specific carrier protein for iron May also be decreased with malnutrition, inflammation, and chronic infection

Question 35

When to check lead level in children?

Answer 35

9-12 months 24 months

Question 36

How to evaluate for hemoglobinopathy?

Answer 36

Hemoglobin electrophoresis But may not be accurate in setting of iron def 2/2 decreased Hgb A2 synthesis (ex/beta thal trait) OR alpha thal trait after newborn period

Question 37

What are risk factors in adolescents for IDA?

Answer 37

Rapid growth Blood loss (menstruation, GI loss, hematuria, H. pylori)

Question 38

What is the dosing of iron treatment for adolescents with IDA?

Answer 38

60-100 mg of elemental Fe divided twice daily 1-2 tabs of ferrous sulfate 325 mg (each contains 65 mg of elemental iron/tablet)