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medicaldump.com

  1. 1. Thalassemia
  2. 2. Thalassemia: Impaired globin gene production Hgb A tetramer globin globin globin globin
  3. 3. Globin chain synthesiscluster - chromosome 16 Gower 1 Portland Embryonic Gower II F Fetal <1% G A A2cluster - chromosome 11
  4. 4. Thalassemia• Organization of globin genes cluster - chromosome 16 cluster - chromosome 11 G A 2 1 G A 2 1• Decreased production of normal globin chains – thalassemia—deficiency of gene(s) – thalassemia—deficiency of gene(s)
  5. 5. Alpha Thalassemia: Clinical Features• Absence of 1–2 alpha X X chains XX X – Common – Asymptomatic – Does not require therapy X• Absence of 3 alpha chains XX (Hgb H disease) – Microcytic anemia (Hgb 7–10) – Splenomegaly XX• Absence of 4 alpha chains XX – Hydrops fetalis (non-viable)
  6. 6. Alpha Thalassemia: Laboratory Findings Hgb MCV Chains (g/dl) (fl) Hgb Analysis / Normal Normal Normal /- 12–14 75–85 Normal Normal with Hgb Barts ( -/ - or --/ 11–13 70–75 4); Hgb H ( 4) (small) Normal with Hgb Barts ( -/-- 7–10 50–60 4); Hgb H ( 4) (large)--/-- - - Not viable
  7. 7. Hypochromic Microcytic RBCs: Alpha ThalassemiaAlpha thalassemia trait Alpha thalassemia ( -/--) Photomicrographs from American Society of Hematology Slide Bank
  8. 8. Beta ThalassemiaClinical Genotype Hgb (g/dl) Hgb A2 Hgb FsyndromeMinor (Trait) + or ° 10–13 + +Intermedia + / + 7–10 + ++Major + or(Cooley’s <7 + +++ °anemia)
  9. 9. Beta Thalassemia MajorSkeletal – Osteoporosis due to bone marrow expansion – Pneumatization of the sinuses is delayed by expanded hematopoiesis• Dilated cardiomyopathy secondary to severe anemia• Growth and development delayed• Hepatomegaly due to extramedullary hematopoiesis
  10. 10. Microcytic Hypochromic Anemia:Beta Thalassemia Major
  11. 11. Approach to Beta Thalassemia• thalassemia trait – Screening/counseling• thalassemia intermedia/major – Screening/counseling – RBC transfusion therapy (+ iron chelation therapy) – Agents to increase hemoglobin F (hydroxyurea) – Bone marrow transplantation

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