Treatment of Severe Iron Deficiency with Symptomatic Presentation
This patient with a ferritin of 3 ng/mL and symptomatic iron deficiency (dizziness, fatigue, heart palpitations) requires immediate intravenous iron therapy rather than oral supplementation, as oral iron is inadequate for severe deficiency and the patient is symptomatic. 1
Immediate Management Approach
Initial Assessment Required
- Measure hemoglobin to determine if iron deficiency anemia is present (anemia defined as Hb <12 g/dL in females, <13 g/dL in males). 2
- Obtain transferrin saturation (iron/total iron binding capacity × 100) to confirm absolute iron deficiency (typically <20%). 1, 2
- Check for underlying blood loss sources, particularly gastrointestinal pathology including malignancy, as this ferritin level mandates evaluation for chronic bleeding. 1
- Assess renal function (serum creatinine and glomerular filtration rate) to evaluate for chronic kidney disease as a contributing factor. 1
- Exclude inflammatory conditions by measuring C-reactive protein, as inflammation can mask iron deficiency. 1, 3
- Consider thyroid function testing, as thyroid dysfunction commonly coexists with iron deficiency. 1
Why Intravenous Iron is Preferred
Oral iron is insufficient for this patient because:
- Severe iron deficiency (ferritin <30 ng/mL) with symptoms requires rapid repletion that oral iron cannot provide. 1, 2
- Oral iron absorption is poor in severe deficiency states, with only 21% of non-responders to initial oral therapy responding to continued oral treatment, compared to 65% responding to IV iron. 1
- Symptomatic patients (fatigue, dizziness, palpitations) benefit from the faster response achieved with IV iron. 1
- Gastrointestinal side effects of oral iron (nausea, constipation, dyspepsia) lead to poor compliance and treatment failure. 1
Recommended IV Iron Regimen
Ferric carboxymaltose is the preferred IV iron formulation based on the strongest evidence:
- Dosing: 500-1000 mg IV infusion, with ability to give up to 1000 mg in a single dose. 1
- Administration: 500 mg dose requires 6 minutes minimum infusion time; 1000 mg dose requires 15 minutes minimum. 1
- Repeat dosing: Iron status should be re-evaluated 3 months after initial treatment, and re-treatment initiated when ferritin drops below 100 ng/mL. 1
- No test dose required for ferric carboxymaltose, unlike low molecular weight iron dextran. 1
Alternative: Oral Iron (Only if IV Not Available)
If IV iron is truly not accessible:
- Ferrous sulfate 325 mg (65 mg elemental iron) once daily or every other day is the recommended oral regimen. 4, 2, 5
- Alternate-day dosing may improve absorption and reduce side effects, as daily dosing increases hepcidin levels that inhibit iron absorption. 1
- Monitor response with repeat hemoglobin and ferritin after 8-10 weeks. 3
- Switch to IV iron if no response (Hb increase <1 g/dL after 2 weeks of oral therapy). 1
Critical Pitfalls to Avoid
- Do not perform routine phlebotomy in this patient—the symptoms are from iron deficiency, not hyperviscosity. 1
- Avoid early re-evaluation (within 4 weeks of IV iron) as ferritin levels increase markedly post-infusion and cannot accurately reflect iron status during this period. 1
- Do not use high-dose oral iron (200 mg three times daily)—this outdated regimen increases side effects without improving efficacy. 5
- Do not ignore the underlying cause—with ferritin this low, gastrointestinal blood loss must be investigated. 1, 2
Expected Outcomes
- Symptom improvement (fatigue, dizziness, palpitations) typically occurs within 2-4 weeks of IV iron administration. 1
- Hemoglobin increase of 1-2 g/dL expected within 4 weeks. 1
- Quality of life improvements are independent of anemia correction and relate to iron repletion itself. 1