How to manage a patient with iron deficiency anemia?

Management of Iron Deficiency Anemia

This patient has iron deficiency anemia requiring oral iron supplementation with ferrous sulfate 200 mg three times daily for at least 3 months after correction of anemia to replenish iron stores. 1

Diagnosis Confirmation

The laboratory values clearly indicate iron deficiency anemia:

• Hemoglobin 8 g/dL (severe anemia)
• Normal MCV (93) - note that despite being iron deficient, MCV is not yet microcytic
• Low serum iron (19)
• Low transferrin saturation (7%)
• Ferritin 118 ng/mL - may appear normal but can be falsely elevated in inflammatory states

Treatment Algorithm

1. Iron Supplementation

• First-line therapy: Oral ferrous sulfate 200 mg three times daily 1
• Alternative oral preparations if not tolerated: ferrous gluconate or ferrous fumarate 1
• Consider liquid preparation if tablets are not tolerated 1
• Add ascorbic acid to enhance iron absorption if response is poor 1

2. Duration of Therapy

• Continue treatment until anemia is corrected
• Continue for an additional 3 months after normalization of hemoglobin to replenish iron stores 1
• Expected hemoglobin rise: 2 g/dL after 3-4 weeks 1

3. Monitoring Response

• Check hemoglobin after 3-4 weeks of therapy
• If hemoglobin doesn't rise by 2 g/dL, consider:
  • Poor compliance
  • Misdiagnosis
  • Continued blood loss
  • Malabsorption
  • Concomitant PPI use (may impair iron absorption) 2

4. Follow-up

• Monitor hemoglobin and red cell indices every 3 months for one year, then after another year 1
• Additional oral iron should be given if hemoglobin or MCV falls below normal 1
• Consider ferritin estimation in doubtful cases 1

Investigation for Underlying Cause

Identifying and treating the underlying cause is essential:

For patients > 45 years:

• Upper GI endoscopy with small bowel biopsy
• Colonoscopy or barium enema
• Check for urinary tract tumors (exclude hematuria) 1

For patients < 45 years:

• If upper GI symptoms: endoscopy and small bowel biopsy
• Test for celiac disease (antiendomysial antibody determinations)
• Colonic investigation only if specific indications 1

Common causes to investigate:

• Bleeding (menstrual, gastrointestinal)
• Impaired iron absorption (atrophic gastritis, celiac disease, bariatric surgery)
• Inadequate dietary iron intake
• Pregnancy 3
• Chronic inflammatory conditions (IBD, CKD, heart failure) 3

Special Considerations

• Proton pump inhibitors: May decrease oral iron absorption, requiring higher doses or longer duration of therapy 2
• Severe anemia: Consider parenteral iron if:
  • Intolerance to at least two oral preparations
  • Non-compliance
  • Impaired absorption
  • Chronic inflammatory conditions 1, 3

Common Pitfalls to Avoid

1. Failure to identify underlying cause: Up to 85% of patients with iron deficiency anemia have an identifiable gastrointestinal cause, even without GI symptoms 4

2. Premature discontinuation of therapy: Continuing iron therapy for 3 months after hemoglobin normalization is essential to replenish stores 1

3. Overlooking non-bleeding causes: Atrophic gastritis, celiac disease, and H. pylori infection can cause iron deficiency without overt bleeding 4

4. Inadequate follow-up: Regular monitoring is needed to ensure sustained response and detect recurrence 1

5. Misinterpreting normal MCV: Iron deficiency can present with normal MCV before developing microcytosis 5