What is the management for microcytic hypochromic anemia?

Management of Microcytic Hypochromic Anemia

Start oral ferrous sulfate 200 mg three times daily immediately and simultaneously investigate the underlying cause of iron deficiency. 1

Diagnostic Confirmation

Your lab values (MCV 71.9 fL, MCH 21.7 pg, MCHC 30.2 g/dL) confirm microcytic hypochromic anemia and strongly suggest iron deficiency as the primary etiology. 1

Check serum ferritin first - this is the single most useful diagnostic marker:

• Ferritin <15 μg/L indicates absent iron stores 1
• Ferritin <30 μg/L indicates low body iron stores 1
• A cut-off of 45 μg/L provides optimal sensitivity and specificity for iron deficiency in clinical practice 1

If ferritin is normal or elevated despite microcytic anemia, add transferrin saturation to detect functional iron deficiency or anemia of chronic disease. 1, 2

Check RDW (red cell distribution width):

• RDW >14.0% with low MCV strongly suggests iron deficiency anemia 1
• RDW ≤14.0% with low MCV suggests thalassemia minor 1

Immediate Treatment Protocol

Ferrous sulfate 200 mg (65 mg elemental iron) three times daily, taken separately from meals 1, 3, 4

• Do not crush or chew tablets 4
• Continue for at least 3 months after hemoglobin normalizes to replenish iron stores 1, 3
• Adding ascorbic acid (vitamin C) enhances iron absorption 1

Alternative oral formulations if ferrous sulfate is not tolerated:

• Ferrous gluconate 1
• Ferrous fumarate 1

Investigate the Underlying Cause

Assume gastrointestinal blood loss until proven otherwise in any adult with iron deficiency. 3

Mandatory investigations:

• Stool guaiac test for occult GI bleeding 3
• Detailed menstrual history if female (most common cause in premenopausal women) 3
• Dietary assessment for inadequate iron intake 3

Men with Hb <110 g/L or non-menstruating women with Hb <100 g/L warrant fast-track GI referral for endoscopic evaluation to exclude malignancy. 1

Monitoring Schedule

Recheck CBC at 2 weeks to confirm response to therapy:

• Expected hemoglobin rise ≥10 g/L within 2 weeks confirms iron deficiency 1, 3
• Failure to respond requires investigation for non-compliance, ongoing blood loss, malabsorption, or alternative diagnoses 1

Long-term monitoring:

• Check hemoglobin and red cell indices every 3 months for 1 year 1, 3
• Then recheck after an additional year 1
• Provide additional oral iron if hemoglobin or MCV falls below normal 1

When to Consider Intravenous Iron

Switch to IV iron if: 1, 3

• Documented malabsorption is present
• True intolerance to all oral formulations
• Blood losses exceed maximal oral replacement capacity
• Failure to respond to adequate oral iron after 4 weeks

Expected response: hemoglobin increase ≥2 g/dL within 4 weeks of IV iron 1, 3

Red Flags Requiring Further Workup

Consider alternative diagnoses if:

• Normal or elevated ferritin with persistent microcytic anemia (suggests anemia of chronic disease or genetic disorder) 3
• Persistent microcytosis despite iron repletion (consider thalassemia trait) 3
• Family history of microcytic anemia (test for thalassemia with hemoglobin electrophoresis) 1
• MCV disproportionately low relative to degree of anemia 1

For genetic disorders of iron metabolism:

• IRIDA (iron-refractory iron deficiency anemia) requires IV iron as oral iron is ineffective 1
• X-linked sideroblastic anemia (ALAS2 defects) responds to pyridoxine 50-200 mg daily initially, then 10-100 mg daily lifelong 1, 5

Critical Pitfalls to Avoid

Do not stop iron therapy when hemoglobin normalizes - continue for 3 months to replenish stores or relapse will occur. 3

Screen for combined deficiencies - iron deficiency can coexist with B12 or folate deficiency. 1

Do not assume all microcytic anemia is iron deficiency - anemia of chronic disease, thalassemia, and sideroblastic anemia must be differentiated to avoid unnecessary or harmful iron therapy. 1, 6