What is the appropriate management for a patient with microcytic anemia and low iron stores?

Management of Microcytic Anemia with Low Iron Stores

The first-line treatment for microcytic anemia with low iron stores (MCV 81, MCH 24.2, MCHC 30, ferritin 12, iron percent saturation 8%) is oral iron supplementation with ferrous sulfate 200 mg twice daily for 3 months after hemoglobin normalization to replenish iron stores. 1

Diagnosis Confirmation

The laboratory values clearly indicate iron deficiency anemia:

• MCV 81 (microcytic)
• MCH 24.2 and MCHC 30 (hypochromic)
• Ferritin 12 (severely depleted, normal >30 μg/L)
• Iron percent saturation 8% (severely depleted, normal >16%)

Treatment Protocol

Oral Iron Therapy

• First-line treatment: Ferrous sulfate 200 mg twice daily (providing approximately 65 mg of elemental iron per tablet) 2, 1
• Alternative formulations if ferrous sulfate is not tolerated:
  • Ferrous gluconate 300 mg (37 mg elemental iron)
  • Ferrous fumarate 210 mg (69 mg elemental iron) 1
• Administration: Take on an empty stomach, 1 hour before or 2 hours after meals to maximize absorption 1
• Duration: Continue for 3 months after hemoglobin normalizes to adequately replenish iron stores 2, 1

Managing Side Effects

• If gastrointestinal side effects occur (constipation, nausea, diarrhea):
  • Consider taking with food (though this reduces absorption by 40-50%)
  • Try alternate-day dosing
  • Lower doses may be better tolerated and still effective 2, 1
• Adding ascorbic acid (250-500 mg twice daily with iron) may enhance absorption, though evidence for effectiveness is limited 2

Monitoring Response

• Check hemoglobin after 4 weeks of treatment
• Expect hemoglobin to rise by approximately 2 g/dL after 3-4 weeks
• Monitor ferritin levels to ensure they increase toward normal (>30 μg/L) 1
• If no improvement after 4 weeks, consider:
  • Poor compliance
  • Continued blood loss
  • Malabsorption
  • Need for alternative treatment approach 1

Indications for Intravenous Iron

Consider intravenous iron therapy if:

• Intolerance to oral iron despite modifications
• No improvement in iron parameters within 2 weeks of oral therapy
• Severe anemia
• Conditions with impaired iron absorption 1

Available IV options include:

• Iron sucrose (Venofer): 200 mg over 10 minutes
• Ferric carboxymaltose (Ferinject): 1000 mg over 15 minutes
• Iron dextran (Cosmofer): 20 mg/kg over 6 hours 2, 3

Caution: Anaphylaxis can occur with IV iron; resuscitation facilities should be available 2

Investigation of Underlying Cause

• Premenopausal women: Assess menstrual blood loss
• Men and postmenopausal women: Bidirectional endoscopy to rule out gastrointestinal bleeding 1
• Consider other causes of microcytic anemia if iron therapy fails:
  • Thalassemia
  • Anemia of chronic disease
  • Sideroblastic anemia 4

Follow-up

• Continue iron therapy for 3 months after hemoglobin normalizes
• Monitor ferritin levels every 6-12 months after treatment completion
• Consider intermittent oral supplementation for high-risk patients to maintain iron stores 1

Common Pitfalls to Avoid

1. Inadequate duration of therapy: Many patients stop iron too early, before stores are replenished 5
2. Failure to investigate underlying cause: Especially important in men and postmenopausal women 1
3. Overreliance on hemoglobin response: Iron stores may lag behind blood morphology improvement 3
4. Missing concomitant conditions: Other causes of microcytic anemia may coexist with iron deficiency 6