thalassemia

Introduction

In 1925, Cooley described a group of children with severe anemia, skeletal & facial abnormalities, splenomegaly, erythrocytes with bizarre morphology, & circulating nucleated red cells. Thus originated the term Cooley's anemia for beta thalassemia major. Since these children were of Italian or Greek ancestry, the term thalassemia (the sea in the blood) was adopted.

The thalassemias are inherited disorders characterized by hypochromic, microcytic anemia secondary to decreased synthesis of one of the globin chains.

Epidemiology

• Mediterranean: Italy, Greece,
• Middle east: Arabian peninsula, Turkey, Iran
• Asia: India, Thailand, Cambodia, southern China
• immigrants from these areas

Pathology

• imbalance in globin chain synthesis results in precipitation of hemoglobin in maturing red cells & aggregation into protein inclusions (Heinz bodies) with membrane changes & hemolysis
• marked deficiency in alpha-globin or beta-globin synthesis results in clinically significant reduction of hemoglobin A synthesis & ineffective erythropoiesis

Genetics

• family history of congenital anemia

Laboratory

• complete blood count
  • anemia minimal
    • RBC count may be increased or normal
      • > 5 x 10E12/L (Fe deficiency < 5 x 10E12/L)
  • RDW < 16 (Fe deficiency > 16)
  • MCV may be very low (microcytosis)
• peripheral smear: target cells
• hemoglobin electrophoresis (see specific thalassemia)
• see ARUP consult

Complications

• iron overload requiring chelation therapy

Differential diagnosis

• iron-deficiency anemia (see beta-thalassemia)

Management

• supportive
  • folate supplementation
  • avoid iron supplementation
• splenectomy for transfusion-dependent thalassemia
• bone marrow transplant for severe thalassemia

More general terms

• hemoglobinopathy
• hemolytic anemia
• microcytic anemia

More specific terms

• alpha thalassemia
• beta thalassemia

Patient information

thalassemia patient information