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

Management of Microcytic Hypochromic Anemia

Start oral ferrous sulfate 200 mg three times daily immediately while simultaneously investigating the underlying cause, as iron deficiency is the most likely diagnosis given these laboratory values. 1

Diagnostic Interpretation

Your laboratory values reveal:

• Low MCH (25.0 pg) and low MCHC (30.3 g/dL) confirm hypochromic microcytic anemia 1
• RBC count is normal-to-elevated (5.31), which is typical for iron deficiency where the bone marrow attempts to compensate by producing more cells, albeit defective ones 1

The critical next step is checking the RDW (red cell distribution width):

• RDW >14.0% strongly suggests iron deficiency anemia 2
• RDW ≤14.0% suggests thalassemia minor 2

Initial Diagnostic Workup

Order these tests immediately:

• Serum ferritin (most specific test for iron deficiency): <45 μg/L confirms iron deficiency with optimal sensitivity and specificity 2
• Transferrin saturation (more sensitive than hemoglobin alone for detecting iron deficiency) 2
• Complete blood count with RDW to differentiate iron deficiency from thalassemia 2, 1
• Stool guaiac test to detect occult GI bleeding, as gastrointestinal blood loss should be assumed until proven otherwise 1

Treatment Protocol

First-line therapy:

• Ferrous sulfate 200 mg (65 mg elemental iron) three times daily, taken separately from meals 1
• Continue for at least 3 months after hemoglobin normalizes to replenish iron stores 2, 1
• Add ascorbic acid (vitamin C) to enhance absorption 2, 1

Alternative formulations if ferrous sulfate not tolerated:

• Ferrous gluconate or ferrous fumarate 2, 1

Investigating the Underlying Cause

In females: Obtain detailed menstrual history (most common cause in premenopausal women) 1

In all patients:

• Assume GI blood loss until proven otherwise 1
• Assess dietary iron intake 1
• Consider celiac disease, H. pylori infection, or other malabsorption causes if no obvious source 1

Monitoring Schedule

• Recheck CBC at 2 weeks: Expect hemoglobin rise ≥10 g/L (≥1 g/dL), confirming iron deficiency 2, 1
• Monitor hemoglobin and red cell indices every 3 months for 1 year, then annually 2, 1

Red Flags Requiring Further Investigation

Failure to respond to oral iron after 4 weeks indicates:

• Malabsorption (consider IV iron) 1
• Ongoing blood loss exceeding replacement capacity 1
• Alternative diagnosis: thalassemia trait (especially if RDW normal/near-normal and family history present) 2, 1
• Genetic disorders of iron metabolism (IRIDA, TMPRSS6 defects) 2
• Sideroblastic anemia (consider pyridoxine/vitamin B6 trial: 50-200 mg daily) 2

Normal or elevated ferritin with microcytic anemia suggests:

• Anemia of chronic disease 1
• Genetic disorder of iron metabolism 2, 1

Intravenous Iron Indications

Switch to IV iron if:

• Documented malabsorption 1
• True intolerance to all oral formulations 1
• Blood losses exceeding maximal oral replacement capacity 1
• Expected response: hemoglobin increase ≥2 g/dL within 4 weeks 2, 1

Critical Pitfalls to Avoid

• Never stop iron therapy when hemoglobin normalizes—continue for 3 months to replenish stores or relapse will occur 1
• Screen for combined deficiencies: Iron deficiency can coexist with B12 or folate deficiency 2, 1
• Consider vitamin B6 deficiency in patients with prior GI surgery or malabsorption who fail iron therapy 3
• Persistent microcytosis despite iron repletion mandates hemoglobin electrophoresis to rule out thalassemia trait 1