What is the treatment plan for an 18-month-old child with iron deficiency anemia and possible underlying infection or inflammation?

Treatment Plan for 18-Month-Old with Iron Deficiency Anemia and Concurrent Inflammation

This child requires immediate oral iron supplementation while simultaneously investigating and treating the underlying infection or inflammation, as the laboratory findings demonstrate true iron deficiency despite the confounding inflammatory state. 1

Immediate Diagnostic Priorities

Confirm Iron-Deficient Erythropoiesis

• Order MCV and RDW immediately to characterize the microcytic anemia pattern. The current MCV of 74 fL is already low for age, and an RDW >14% would confirm iron deficiency over thalassemia trait 2, 1
• Measure erythrocyte protoporphyrin (>80 µg/dL in children aged 1-2 years confirms iron-deficient erythropoiesis), as this marker is elevated when insufficient iron is available for hemoglobin synthesis 2, 1
• Check C-reactive protein (CRP) or ESR to quantify the degree of inflammation that is artificially elevating the ferritin from its true depleted state 2, 1

Critical Laboratory Interpretation

The transferrin saturation of 4% is severely low (normal 10-42%), indicating insufficient circulating iron for red blood cell production regardless of ferritin level 1. The ferritin of 25 µg/L appears "low-normal" but is falsely elevated by inflammation—in the absence of infection/inflammation, this child's true ferritin would likely be <15 µg/L, confirming depleted iron stores 2, 1.

Identify and Treat Underlying Inflammation

Investigate the Lymphocytosis

• The lymphocyte count of 11.6 × 10⁹/L (normal 2.0-8.0) with total WBC of 15.1 suggests viral infection or early recovery from infection 2
• Obtain blood film review by hematologist (already ordered) to exclude lymphoproliferative disorders, though viral etiology is most likely at this age 2
• Clinical assessment for active infection: fever, respiratory symptoms, diarrhea, or recent illness history 2

Address Inflammation First

Resolving the underlying inflammation takes priority before aggressive iron supplementation 2. However, given the severe iron deficiency (transferrin saturation 4%, hemoglobin 99 g/L), you cannot wait for complete resolution—start oral iron immediately while treating infection 2.

Iron Supplementation Strategy

Oral Iron Therapy (First-Line)

• Initiate elemental iron 3-6 mg/kg/day divided into 1-2 doses (for an average 18-month-old weighing 11 kg, this equals 33-66 mg elemental iron daily) 3, 4
• Ferrous sulfate is preferred: give 325 mg ferrous sulfate (65 mg elemental iron) once daily or divided 3
• Administer on empty stomach when possible to maximize absorption, but may give with food if gastrointestinal side effects occur 2, 5
• Avoid giving with milk or calcium-rich foods as these inhibit iron absorption 2

Alternative Dosing for Better Tolerance

Alternate-day dosing (every other day) may improve absorption and reduce gastrointestinal side effects in children who do not tolerate daily dosing 2. This approach provides better iron resorption with fewer adverse effects compared to daily dosing.

When to Consider Intravenous Iron

IV iron is not first-line in this age group unless 2, 3, 5:

• Oral iron fails after 3 months of adequate dosing
• Severe gastrointestinal intolerance develops
• Malabsorption is documented (celiac disease, inflammatory bowel disease)
• Ongoing blood loss cannot be controlled
• Hemoglobin drops below 70 g/L requiring urgent correction

Additional Nutritional Deficiencies to Screen

Vitamin B12 and Folate Assessment

Check serum vitamin B12 and folate levels now 6. The CDC recommends that less than 50% of children with anemia are actually iron deficient alone, making evaluation for other causes critical 6. While this child's presentation is consistent with iron deficiency, vitamin B12 deficiency can cause severe megaloblastic anemia and neurological deficits that may not be fully reversible even after correction 6.

Lead Screening

Obtain blood lead level if not recently checked, as lead poisoning can cause both microcytic anemia and is common in toddlers with pica or environmental exposure 6, 7.

Monitoring and Follow-Up

Short-Term Reassessment (2-4 Weeks)

• Recheck hemoglobin and reticulocyte count at 2-4 weeks to confirm response to oral iron (expected hemoglobin increase of 1-2 g/dL) 3, 4
• Assess resolution of infection/inflammation with repeat CRP/ESR and complete blood count 2, 1
• Evaluate medication tolerance and adherence 2, 5

Long-Term Monitoring (8-12 Weeks)

• Repeat complete iron panel (serum iron, ferritin, transferrin saturation) at 8-10 weeks, not earlier, as ferritin levels remain falsely elevated immediately after treatment 2
• Continue iron supplementation for 3-6 months after hemoglobin normalizes to replenish iron stores 3, 5, 4
• Target ferritin >30 µg/L and transferrin saturation >20% to confirm adequate iron repletion 3

Common Pitfalls to Avoid

Do Not Wait for Inflammation to Resolve Completely

The guideline recommendation to "resolve underlying inflammation first" applies to chronic inflammatory conditions like cystic fibrosis or inflammatory bowel disease 2. In this acute setting with severe iron deficiency (transferrin saturation 4%), delaying iron supplementation would worsen anemia and impair growth 2, 3.

Do Not Rely on Ferritin Alone

Ferritin is an acute phase reactant and will be falsely elevated by any infection or inflammation 2, 1. The transferrin saturation of 4% is the most reliable indicator of functional iron deficiency in this inflammatory state 2, 1.

Do Not Overlook Dietary Counseling

Increase dietary heme iron (red meat, poultry) and non-heme iron (fortified cereals, beans) while avoiding excessive cow's milk intake (limit to 16-24 oz/day) which inhibits iron absorption 2, 7, 4.

Do Not Recheck Labs Too Early

Avoid rechecking ferritin before 8 weeks as levels remain artificially elevated after iron administration, leading to premature discontinuation of therapy 2.