Treatment of Anemia
The treatment of anemia must be tailored to the specific underlying cause, with iron supplementation being the first-line therapy for iron deficiency anemia, the most common type of anemia. 1
Diagnostic Approach
Before initiating treatment, proper diagnosis is essential:
Laboratory evaluation:
- Complete blood count with hemoglobin, hematocrit, MCV, RDW
- Iron studies (serum ferritin, transferrin saturation)
- Reticulocyte count
- Vitamin B12 and folate levels if indicated
- C-reactive protein (for inflammation)
- Renal function tests
Classification by MCV:
- Microcytic (MCV <80 fL): Iron deficiency, thalassemia, anemia of chronic disease
- Normocytic (MCV 80-100 fL): Acute blood loss, renal disease, anemia of chronic disease
- Macrocytic (MCV >100 fL): Vitamin B12/folate deficiency, alcoholism, medications
Treatment Based on Etiology
1. Iron Deficiency Anemia
- Oral iron supplementation: 3 mg/kg/day for children; 60-200 mg elemental iron daily for adults 1
- Duration: Continue for 2-3 months after hemoglobin normalizes to replenish stores
- Parenteral iron: Consider when oral therapy fails, is not tolerated, or in cases of malabsorption
- Investigate source: GI evaluation needed in men and postmenopausal women (60-70% will have a source of bleeding) 1
2. Vitamin Deficiencies
- B12 deficiency: Oral B12 (1000-2000 mcg daily) or IM B12 (1000 mcg monthly) 2
- Folate deficiency: Oral folate 1-5 mg daily
3. Anemia of Chronic Disease/Inflammation
- Primary approach: Treat underlying condition
- Iron therapy: Only if concurrent iron deficiency exists
- ESAs: Consider only in specific circumstances with hemoglobin <10 g/dL 1, 3
4. Genetic/Inherited Anemias
- Sideroblastic anemia due to SLC25A38 defects: HSCT is the only curative option; symptomatic treatment includes erythrocyte transfusions and chelation therapy 1
- XLSA due to ALAS2 defects: Initial treatment with pyridoxine 50-200 mg/day; monitor for response 1
5. Cancer-Related Anemia
- Approach based on cause:
- Blood loss: Address source
- Chemotherapy-induced: Consider ESAs only when Hb ≤10 g/dL and not for curative intent treatment 1
- Bone marrow infiltration: Treat underlying malignancy
Special Considerations
Erythropoiesis-Stimulating Agents (ESAs)
Indications: Limited to:
- Anemia due to chronic kidney disease
- Chemotherapy-induced anemia (non-curative intent)
- Anemia due to zidovudine in HIV patients 3
Contraindications:
- Cancer patients not receiving chemotherapy
- Cancer patients receiving curative-intent therapy
- Patients with uncontrolled hypertension 3
Risks: Increased mortality, thromboembolism, stroke, and tumor progression 1, 3
Blood Transfusions
- Indications: Severe symptomatic anemia or acute blood loss with hemodynamic instability
- Threshold: Use restrictive strategy (Hb 7-8 g/dL) in most patients, including those with coronary heart disease 1
- Risks: Iron overload, infection transmission, immune suppression 1
Monitoring Response
- Recheck hemoglobin after 4 weeks of treatment
- An increase in Hb ≥1 g/dL confirms response to iron therapy 1
- Monitor iron status during treatment to detect iron loading
- For ESA therapy, monitor hemoglobin weekly until stable 3
Common Pitfalls to Avoid
- Treating anemia without identifying the cause
- Overlooking GI malignancy in men and postmenopausal women with iron deficiency
- Inappropriate use of ESAs without considering risks
- Inadequate duration of iron therapy (stopping once hemoglobin normalizes)
- Missing concurrent nutritional deficiencies (e.g., B12 deficiency with iron deficiency)
- Failure to monitor response to therapy and adjust treatment accordingly
Remember that the goal of anemia treatment is to improve morbidity, mortality, and quality of life by addressing the underlying cause while minimizing risks associated with therapy.