Approach to Treating Anemia
The treatment of anemia should begin with identifying the underlying cause through appropriate diagnostic testing, followed by targeted therapy based on the specific etiology, with oral iron supplementation being the first-line treatment for iron deficiency anemia. 1, 2
Diagnosis and Classification
- Anemia is defined as a reduction in hemoglobin concentration, red-cell count, or packed cell volume below normal levels 1
- Severity classification:
- Initial diagnostic workup should include:
- Complete blood count (CBC) with indices to characterize anemia 1
- Peripheral blood smear to confirm RBC morphology 1, 2
- Morphologic classification based on mean corpuscular volume (MCV) to identify underlying cause 1
- Assessment for occult blood loss in stool and urine 2
- Iron studies including serum iron, ferritin, and transferrin saturation 3
Treatment Algorithm by Etiology
1. Iron Deficiency Anemia
- First-line therapy: Oral iron supplementation - ferrous sulfate 324 mg (65 mg elemental iron) daily or twice daily between meals 2, 4
- Lower doses or alternative formulations (ferrous fumarate or gluconate) may be better tolerated 4
- Add ascorbic acid (250-500 mg twice daily) to improve absorption 4
- Continue treatment for 2-3 months after hemoglobin normalization to replenish iron stores 2, 3
- Intravenous iron therapy indicated when:
2. Vitamin B12 Deficiency
- For pernicious anemia: Intramuscular vitamin B12 100 mcg daily for 6-7 days, then alternate days for 7 doses, then every 3-4 days for 2-3 weeks, followed by 100 mcg monthly for life 5
- For patients with normal intestinal absorption: Similar initial treatment followed by oral B12 maintenance 5
- Avoid intravenous administration as most of the vitamin will be lost in urine 5
3. Anemia of Chronic Disease/Inflammation
- Treat the underlying inflammatory condition to enhance iron absorption 1, 6
- Consider intravenous iron in cases with functional iron deficiency 6, 7
- Erythropoiesis-stimulating agents (ESAs) may be considered in specific situations:
4. Cancer-Related Anemia
- Evaluate for multiple potential causes including chemotherapy effects, nutritional deficiencies, and bone marrow infiltration 1
- Assess and direct therapy towards factors related to production, destruction, or loss of red cells 8
- ESAs may be considered for chemotherapy-induced anemia with appropriate hemoglobin thresholds 1
- Screen for renal function prior to myelosuppressive chemotherapy 8
5. Myelodysplastic Syndromes
- Exclude other causes of anemia such as gastrointestinal bleeding, hemolysis, renal disease, and nutritional deficiency 8
- Consider lenalidomide for patients with del(5q) 8
- For patients with normal cytogenetics and low serum erythropoietin levels, consider erythropoietin therapy 8
Transfusion Therapy
- Reserve for severe symptomatic anemia or when rapid correction is needed 2, 4
- Use restrictive transfusion strategy (hemoglobin threshold 7-8 g/dl) 1, 2
- Be aware of potential complications including iron overload, infection transmission, and immune suppression 2
Monitoring and Follow-up
- For iron deficiency anemia: Repeat hemoglobin measurement after 4 weeks of treatment 1, 2
- Monitor hemoglobin levels and red blood cell indices every 3 months for 1 year and then annually 4
- Administer additional iron supplementation if hemoglobin or MCV fall below normal 4
Common Pitfalls to Avoid
- Failure to identify and treat the underlying cause can lead to recurrence 2, 9
- Overlooking occult gastrointestinal blood loss in men and postmenopausal women with iron deficiency 3, 9
- Using ESAs without considering risks including hypertension, thromboembolism, and potential tumor progression in cancer patients 2
- Overreliance on transfusions rather than addressing the underlying cause 2, 3