What is the recommended number of intravenous iron infusion rounds for a patient with severe iron deficiency anemia and a hemoglobin level of 7.4 after receiving two units of packed red blood cells (PRBCs)?

Iron Infusion Protocol for Severe Iron Deficiency Anemia

For a patient with severe iron deficiency anemia (hemoglobin 7.4 g/dL after blood transfusion), 1-2 rounds of intravenous iron infusion are recommended to fully replenish iron stores and prevent recurrence of anemia.

Assessment of Iron Deficiency Severity

This 40-year-old female presented with critically low hemoglobin (4.9 g/dL) due to iron deficiency anemia, requiring emergency blood transfusion. After receiving two units of packed red blood cells, her hemoglobin improved to 7.4 g/dL, but remains below normal range. This represents severe iron deficiency requiring aggressive management.

IV Iron Dosing Protocol

Recommended Approach:

1. Calculate total iron deficit based on hemoglobin and body weight:

   • For hemoglobin 70-100 g/L (7.0-10.0 g/dL):
     • If <70 kg: 1500 mg total iron
     • If ≥70 kg: 2000 mg total iron 1

2. Administration schedule:

   • Use IV iron formulations that can replace iron deficits with 1-2 infusions 2
   • Options include:
     • Ferric carboxymaltose: 750 mg IV × 2 doses 7 days apart (for patients ≥50 kg) 1
     • Iron derisomaltose: can be administered as a single infusion of 20 mg/kg with no ceiling 3

Rationale for IV Iron Over Oral Iron

IV iron is strongly preferred in this case because:

• The severity of anemia (initial Hb 4.9 g/dL) indicates profound iron deficiency
• IV iron provides faster repletion of iron stores than oral iron 1
• IV iron bypasses gastrointestinal absorption issues 1
• The British Society of Gastroenterology recommends parenteral iron for patients with moderately severe anemia 2

Monitoring Protocol

1. Short-term monitoring:

   • Check hemoglobin after 4 weeks
   • Complete iron studies (ferritin, TSAT) after 4-8 weeks 1
   • Target parameters:
     • Hemoglobin increase of 1-2 g/dL within 4-8 weeks
     • Ferritin ≥50 ng/mL
     • Transferrin saturation >20% 1

2. Long-term monitoring:

   • Monitor blood count every 6 months initially to detect recurrent IDA 2
   • Check iron parameters (ferritin, TSAT) every 3 months 2

Important Considerations

• Diagnostic workup: This patient requires thorough gastrointestinal evaluation to identify the underlying cause of severe iron deficiency 2
• Safety precautions: While modern IV iron preparations have low risk of severe reactions (<1% of patients), monitor for hypersensitivity reactions during infusion 3
• Potential complications: Be aware of hypophosphatemia risk with ferric carboxymaltose (affecting 50-74% of patients in clinical trials) 3

Special Considerations for Women of Reproductive Age

• Heavy menstrual bleeding should be evaluated as a potential cause
• If ongoing blood loss is identified, the underlying cause must be treated to prevent recurrence 1

This aggressive approach with 1-2 rounds of IV iron infusion will rapidly correct the severe iron deficiency, improve clinical outcomes, and prevent complications of chronic anemia.