What is the appropriate management for a patient with microcytic hypochromic anemia?

Management of Microcytic Hypochromic Anemia

Start with oral ferrous sulfate 200 mg three times daily for at least three months after hemoglobin correction, as this patient's elevated RDW (15.7%) with microcytosis strongly suggests iron deficiency anemia rather than thalassemia trait. 1

Initial Diagnostic Workup

The laboratory pattern guides immediate next steps:

• Check serum ferritin first - this is the most specific test for iron deficiency, with levels <30 μg/L indicating low body iron stores and <45 μg/L providing optimal sensitivity/specificity 1
• Measure transferrin saturation - more sensitive than hemoglobin alone for detecting iron deficiency 1
• The RDW >14.0% with low MCV pattern in this case strongly favors iron deficiency over thalassemia minor (which typically shows RDW ≤14.0%) 1

First-Line Treatment Protocol

Oral iron supplementation is the cornerstone:

• Ferrous sulfate 200 mg three times daily (each 324 mg tablet contains 65 mg elemental iron) for at least 3 months after anemia correction to replenish stores 1, 2
• Add ascorbic acid to enhance absorption 1
• Alternative formulations (ferrous gluconate or ferrous fumarate) if ferrous sulfate causes intolerable gastrointestinal side effects 1
• Do not crush or chew tablets per FDA labeling 2

Monitoring Response

Expect hemoglobin rise ≥10 g/L (1 g/dL) within 2 weeks - this confirms iron deficiency diagnosis 1

• Monitor hemoglobin and red cell indices at 3-month intervals for one year, then again after another year 1
• Check serum ferritin and transferrin saturation to assess iron store repletion 3
• Provide additional oral iron if hemoglobin or MCV falls below normal 1

When to Consider Alternative Diagnoses

If no response to oral iron within 4 weeks:

• Consider intravenous iron if malabsorption is present (expect ≥2 g/dL hemoglobin increase within 4 weeks) 1
• Test for thalassemia if RDW normalizes or remains near-normal 1
• Evaluate for genetic disorders of iron metabolism or heme synthesis (SLC11A2, STEAP3, SLC25A38, ALAS2 defects) if MCV is extremely low relative to degree of anemia 3
• Consider bone marrow examination for ring sideroblasts if ferritin is normal/high with abnormal iron studies, indicating possible sideroblastic anemia 3

Special Considerations for Genetic Causes

If genetic disorder suspected based on extreme microcytosis or treatment failure:

• ALAS2 defects (X-linked sideroblastic anemia): Trial pyridoxine 50-200 mg daily initially, then maintain lifelong at 10-100 mg daily if responsive 1, 4
• SLC25A38 defects: Hematopoietic stem cell transplantation is the only curative option 3, 4
• STEAP3 defects: Erythrocyte transfusions combined with erythropoietin 1, 4
• Monitor for iron overload with regular ferritin checks and liver MRI in specific cases 1, 4

Common Pitfalls to Avoid

• Don't overlook combined deficiencies - iron deficiency can coexist with B12 or folate deficiency 1
• Don't stop iron too early - continue for 3 months after hemoglobin normalizes to replenish stores 1
• Don't miss malabsorption - consider vitamin B6 deficiency in patients with gastrointestinal surgery who remain refractory to iron 5
• Don't confuse with thalassemia - the elevated RDW in this case argues against thalassemia trait 1, 6