Etiology, Investigations, and Differential Diagnosis of Microcytic Hypochromic Anemia

Introduction

Microcytic hypochromic anemia is characterized by smaller-than-normal red blood cells (RBCs) with reduced hemoglobin concentration. It is commonly associated with iron deficiency but may also result from genetic disorders, chronic diseases, or lead toxicity.

Etiology of Microcytic Hypochromic Anemia

Genetic Causes

• Thalassemia syndromes: Defective hemoglobin production.
• Sideroblastic anemia: Impaired hemoglobin synthesis due to mitochondrial dysfunction.

Nutritional Causes

• Iron deficiency: The most common cause worldwide due to inadequate dietary intake or chronic blood loss.
• Vitamin B6 deficiency: Required for hemoglobin synthesis.

Acquired Causes

• Chronic disease anemia: Impaired iron utilization in chronic inflammatory states.
• Lead poisoning: Disrupts enzymatic pathways involved in hemoglobin synthesis.

Investigations

A thorough diagnostic workup includes laboratory tests and clinical evaluation:

• Complete blood count (CBC): Shows low mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH).
• Iron studies: Ferritin, serum iron, total iron-binding capacity (TIBC) to assess iron status.
• Hemoglobin electrophoresis: Identifies hemoglobinopathies such as thalassemia.
• Bone marrow examination: Assesses erythropoiesis and iron stores.

Differential Diagnosis

• Iron deficiency anemia: Low serum iron and ferritin.
• Thalassemia minor: Normal iron levels but abnormal hemoglobin electrophoresis.
• Sideroblastic anemia: Ringed sideroblasts in bone marrow.
• Anemia of chronic disease: Normal or high ferritin with low serum iron.

Conclusion

Microcytic hypochromic anemia has diverse etiologies requiring comprehensive evaluation. Proper diagnosis allows targeted treatment, improving patient outcomes.