What is the diagnosis and management for a patient with normocytic anemia?

Diagnosis and Management of Microcytic Anemia

Based on the laboratory values provided (RBC 3.81, Hgb 7.6, hct 29.3, MC 77, MCH 19.9, MCHC 25.9, RDW 16.9), this patient has iron deficiency anemia that requires oral iron supplementation as first-line therapy.

Interpretation of Laboratory Values

• The patient has anemia with hemoglobin of 7.6 g/dL (normal: >13 g/dL for men, >12 g/dL for women) 1
• The anemia is microcytic (MCV 77 fL, below the threshold of 80 fL) 1
• Low MCH (19.9) and MCHC (25.9) indicate hypochromia 1
• Elevated RDW (16.9) suggests iron deficiency 1
• These values together strongly point to iron deficiency anemia 1

Diagnostic Algorithm

1. Classification by MCV and reticulocytes:

   • MCV < 80 fL indicates microcytic anemia 1
   • Normal or low reticulocytes suggest non-regenerative anemia 1

2. Differential diagnosis of microcytic anemia with normal/low reticulocytes:

   • Iron deficiency anemia
   • Anemia of chronic disease
   • Thalassemia
   • Lead poisoning (rare)
   • Hereditary microcytic anemia (rare) 1

3. Further workup needed:

   • Serum ferritin (most important test to confirm iron deficiency) 1
   • Transferrin saturation (TSAT) 1
   • CRP (to assess inflammation) 1
   • If ferritin is low (<30 μg/L without inflammation or <100 μg/L with inflammation), iron deficiency is confirmed 1

Management Recommendations

• Begin oral iron supplementation as first-line therapy for iron deficiency anemia 1

  • Ferrous sulfate 325 mg (65 mg elemental iron) 1-3 times daily between meals 1
  • Continue for 3-6 months after hemoglobin normalizes to replenish iron stores 1

• Monitor response:

  • Expect hemoglobin increase of approximately 1-2 g/dL every 2-4 weeks 1
  • Check hemoglobin, reticulocytes, and iron studies after 4-8 weeks of therapy 1

• Consider parenteral iron if:

  • Patient is intolerant to oral iron
  • Poor response to oral iron after 4-8 weeks
  • Severe anemia requiring rapid correction
  • Presence of conditions affecting iron absorption (inflammatory bowel disease, celiac disease) 1

• Investigate underlying cause of iron deficiency:

  • Gastrointestinal bleeding (most common cause in adults)
  • Menstrual blood loss in women
  • Malabsorption
  • Poor dietary intake 1

Important Considerations and Pitfalls

• Don't mistake anemia of chronic disease for iron deficiency:

  • Both can present with microcytic anemia
  • In anemia of chronic disease, ferritin is typically >100 μg/L with low TSAT (<20%) 1
  • Mixed pictures can occur (ferritin 30-100 μg/L with inflammation) 1

• Rule out thalassemia if:

  • Poor response to iron therapy
  • Family history of anemia
  • Ethnic background with high prevalence of thalassemia
  • Microcytosis out of proportion to anemia 1

• Monitor for iron overload during treatment:

  • Avoid exceeding serum ferritin of 500 μg/L, especially in children and adolescents 1
  • Adjust dosing if side effects occur (nausea, constipation, abdominal discomfort) 1

• Consider additional deficiencies that may coexist with iron deficiency:

  • Vitamin B12 and folate levels should be checked if MCV is normal or high, or if response to iron therapy is inadequate 2, 3