What is the diagnosis and treatment for a patient with severe iron deficiency anemia?

Interpretation of Labs: Severe Iron Deficiency Anemia Requiring Intravenous Iron Therapy

The laboratory values show severe iron deficiency anemia requiring intravenous iron therapy due to the extremely low ferritin (2 ng/mL), low iron saturation (5%), and significant anemia (Hgb 8.1 g/dL) with microcytosis (MCV 76.4).

Laboratory Interpretation

The presented labs demonstrate classic findings of iron deficiency anemia:

• Ferritin: 2 ng/mL (severely depleted; normal >45 ng/mL)
• Total iron: 31 (low)
• % saturation: 5% (severely low; normal >20%)
• Hemoglobin: 8.1 g/dL (moderate-severe anemia)
• MCV: 76.4 (microcytic)
• EPO: 151.1 (elevated, compensatory response)
• Haptoglobin: 140 (normal, ruling out hemolysis)

Diagnosis

This is a clear case of severe iron deficiency anemia based on:

• Ferritin <30 ng/mL (diagnostic of absolute iron deficiency) 1
• Transferrin saturation <20% (confirms iron deficiency) 1
• Microcytic anemia (MCV <80)
• Elevated erythropoietin (compensatory mechanism)
• Normal haptoglobin (rules out hemolysis as cause)

Treatment Algorithm

Step 1: Determine Severity and Route of Iron Administration

• Intravenous iron therapy is indicated due to:
  • Severe anemia (Hgb <10 g/dL)
  • Extremely low ferritin (2 ng/mL)
  • Very low transferrin saturation (5%)

Step 2: Choose Appropriate IV Iron Formulation

• Options include:
  • Ferric carboxymaltose: 1000 mg IV over 15 minutes
  • Iron sucrose: 200 mg IV 5 doses (total 1000 mg)
  • Low molecular weight iron dextran: 1000 mg total dose

Step 3: Monitor Response

• Check hemoglobin at day 14
  • Expected response: ≥1.0 g/dL increase 2
• Recheck iron studies at 4-8 weeks

Step 4: Maintenance Therapy

• After successful treatment, monitor iron studies every 3 months for at least a year 1
• Initiate retreatment when ferritin drops below 100 μg/L or hemoglobin falls below gender-specific thresholds 1

Important Clinical Considerations

1. Diagnostic workup for cause of iron deficiency is essential:

   • Gastrointestinal evaluation (upper and lower endoscopy) 1
   • Gynecological evaluation in women of reproductive age
   • Consider celiac disease testing 1

2. Why oral iron is not first-line in this case:

   • Severity of anemia (Hgb <10 g/dL)
   • Extremely low iron stores (ferritin 2 ng/mL)
   • IV iron provides faster correction of anemia 2

3. Pitfalls to avoid:

   • Delaying IV iron in severe deficiency
   • Failing to investigate underlying cause
   • Inadequate dosing (total iron deficit must be calculated)
   • Stopping treatment once hemoglobin normalizes without replenishing stores

4. Target parameters:

   • Aim for ferritin >100 μg/L to prevent recurrence 1
   • Some guidelines suggest targeting ferritin up to 400 μg/L for longer-term prevention 1

Special Considerations

• If inflammatory bowel disease is present, IV iron is particularly indicated 1
• In patients with ongoing blood loss, higher doses of iron and more frequent monitoring may be needed
• Quality of life improvements should be assessed along with laboratory parameters

By implementing this treatment approach, the severe iron deficiency anemia should resolve with significant improvements in hemoglobin, iron stores, and patient symptoms.