THALASEMIA

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  • Types of hemoglobin (MCQ)
    • Hemoglobin A: a 2/b2 globin chains (normal hemoglobin)
    • Hemoglobin F: a2/g2 globin chains (fetal hemoglobin)
    • Hemoglobin A2: a2/d2
  • Normal distribution of Hb in adults is: 96%- HbA 3%- HbF 1%- HbA2
  • There are two a and one b gene on each chromosome, making a total of four a genes and two b genes in each chromosome pair.
  • a Thalassemia
    • Genetic defects causing gene deletions of a chains
    • Epidemiology
      • aa/—thalassemia trait is most common in Asians. (MCQ)
      • a–/a–thalassemia trait is most common in Africans.
    • Pathophysiology
      • Ineffective production of a globin chains causes b globin chains to accumulate. (MCQ)
    • Signs and symptoms
      • Depends on how many of the four foci are deleted or mutated: (MCQ)
        • 1/4 foci involved = silent thalassemia ,Asymptomatic
        • 2/4 foci involved = thalassemia trait ,Mild anemia
        • 3/4 foci involved
          • Hemoglobin H disease
          • Microcytic, hypochromic, hemolytic anemia with marked splenomegaly.
          • Patient may need occasional transfusions.
        • 4/4 foci involved =
          • Hemoglobin Barts
          • hydrops fetalis
          • Incompatible with life
    • Diagnosis
      • Blood smear: Microcytic anemia, hypochromia, target cells, Heinz bodies(MCQ)
      • HbH precipitates on staining with brilliant cresyl blue(MCQ)
  • Beta-thalassemia
    • Gene defects including deletions, abnormalities of transcription and translation, and instability of mRNA in b globin hemoglobin
    • Pathophysiology
      • Ineffective production of b globin chains causes a globin chains to accumulate in the cell.
      • The accumulation of a chains form insoluble aggregates that damage cell membranes.
      • A partial compensatory increase of the d and g chains yields elevated levels of HbA2 (a2d2) or HbF (a2g2). (MCQ)
    • Signs and symptoms
      • b-Thalassemia major (Cooley’s anemia): Associated with jaundice, hep- atosplenomegaly, and jaundice
      • b-Thalassemia minor: Mild or no anemia
    • Diagnosis
      • Elevated HbF and HbA2 measurements on hemoglobin electrophoresis
    • Treatment
      • b-Thalassemia major: (MCQ)
        • Aggressive transfusions
        • Splenectomy to enhance survival of RBCs, bone marrow transplant
      • b-Thalassemia minor: No treatment indicated.
  • Clinical Pearls :
    • Abnormal red blood cell morphology with microcytes, acanthocytes, and target cells. (MCQ)
    • In -thalassemia, elevated levels of hemoglobin A2 or F. (MCQ)
    • The thalassemias are hereditary disorders characterized by reduction in the synthesis of globin chains ( or ).
    • Two copies of the -globin gene are located on chromosome 16, (MCQ)
    • The -globin gene resides on chromosome 11 adjacent to genes encoding the -like globin chains,  and .(MCQ)
    • In cases of severe thalassemia, the marked expansion of the erythroid element in the bone marrow may cause severe bony deformities, osteopenia, and pathologic fractures.
    • Hemoglobin electrophoresis will show the presence of a fast migrating hemoglobin (hemoglobin H), which comprises 10–40% of the hemoglobin. (MCQ)
    • A peripheral blood smear can be stained with supravital dyes to demonstrate the presence of hemoglobin H. (MCQ)
    • Compared to iron deficiency anemia, patients with thalassemia have a(MCQ)
      • lower MCV
      • a more normal red blood count
      • a more abnormal peripheral blood smear at modest levels of anemia.
      • Iron studies are normal.
    • Patients with hemoglobin H disease (MCQ)
      • should take folate supplementation
      • avoid medicinal iron and oxidative drugs such as sulfonamides.
    • Patients with severe thalassemia are maintained on a regular transfusion schedule and receive folate supplementation.
    • Splenectomy is performed if hypersplenism causes a marked increase in the transfusion requirement.
    • Patients with regular transfusion requirements should be treated with iron chelation
    • Subcutaneous infusion of deferoxamine has largely been replaced by the oral agent deferasirox. (MCQ)
    • Allogeneic bone marrow transplantation is the treatment of choice for -thalassemia major(MCQ)


Jenis-Jenis Thalasemia dan Penanganan Thalasemia
MENGENAL THALASEMIA
Periksalah darah anda dan pasangan anda sebelum menikah, jangan sampai anak anda menderita thalasemia seperti anak saya, yang selama hidupnya tergantung pada darah orang lain. THALASEMIA BISA DICEGAH
Thalassemia: Understanding the disease
Though genetic, thalassemia affects a large number of people world over. Here is a video about all you might need to know about the condition
Gene Therapy for Beta Thalassemia
Thalassemia; a genetic calamity
An educational video about Thalassemia, a genetic blood disorder that is leaving its mark on our world.

Thalassemia ¦ Treatment and Symptoms