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THALASAEMIA, b THALASSAEMIA MAJOR - Coggle Diagram

- - - - premature red cell destruction due to
        red cell membrane damage by precipitated aglobin chains.
        
        Shortened red cell lifespan,
        
        ineffective erythropoiesis,
        
        haemodilution.
        
        a chains precipitate with red cell as Heinz bodies,
        
        leading to red cell membrane damage.
        
        These cells are phagocytosed in spleen and liver
        
        causing anaemia,
        
        hepatosplenomegaly
        
        and excess tissue iron stores
  - - - Arise from different types of mutations of b globin gene resulting from single
        base change
        
        More than 100 mutations have been described in different coding sequences eg:
        
        promotor region,
        
        termination region,
        
        splice junctions,
        
        exons,
        
        introns
        
        Transcription defect:
        
        mutation affecting transcriptional promoter sequence.
        Partially preserved synthesis b+ thalassameia
        
        Translation defect
        
        mutation in coding sequence causing stop codon. No synthesis.
        b thalassaemia
        
        mRNA splicing defect
        
        mutation leads to defective mRNA
        
        diagram
- - - - ‘thala’ means sea in Greek
        
        35 million have b Thalassaemia major
        
        table
- - - - Marked
        hepatosplenomegaly
        
        Expansion of bones
  - - - severe
      - Blood film
        
        sever microcytic hypochromic red cell,
        
        anisopoikilocytosis,
        
        basophilic stippling,
        
        prescence of target cells,
        
        tear drop cells and
        
        normoblasts
        
        Serum bilirubin
        
        unconjugated raised
        
        Reticulocytosis
        
        present
        
        MCV, MCH, MCHC
        
        significantly reduced
        
        Platelets
        
        usually normal
        
        Decreased osmotic fragility
        
        1 more item...
    - - Largely supportive
        
        Anaemia: regular blood transfusion (4-6 weeks) to maintain Hb above
        8g/dL
        
        Folic acid supplements
        
        Splenectomy is beneficial in children over
        6 years
        
        Bone marrow transplantation from
        HLA-matched donor provides stem cells,
        
        done at early stage before end organ damage
        
        Cord blood transfusion
        
        1 more item...