01-14-2007, 02:40 PM
MCV : microcytic
Reticulocyte count : < 2 % in mild thal; > 3 % in severe types
Key findings : basophilic stippling ( indicates problem with Hb synthesis ),
Target cells ( an excellent marker of Hb disorders )
Tear drop cells ( possibly due to removal of excess globins chains by macrophages),
Alpha “globins chains in severe Beta “Thalassemia ( Cooley™s anemia; inclusions are toxic leading to hemolysis )
PATHOGENESIS
Decreased Hb synthesis
Alfa- Thalassemia : Asians , Blacks ( decreased Alfa “globin chain synthesis on chromosome 16 )
Beta “Thalassemia : Blacks, Italians, Greeks ( decreased beta “globin chains on chromosome 11 ( point mutation producing splicing defect most common )
Increased synthesis of HbA2 and F.
Beta Thalassemia : Minor and Major ( Cooley's anemia-hemolytic component )
CAUSES:
Autosomal recessive
1-gene deletion : silent carrier
2 gene deletion : Alfa Thalassemia trait
3 “gene deletion : HbH disease, Hemolytic anemia
4-gene deletion :
Hb Bart™s disease. Incompatibility with life. Spontaneous abortion, increased risk of molar disease ( hydatiform mole and choriocarcinoma
EVAL/TREATMENT
Severe Thalassemia do not manifest at birth.
Fist manifestation occur at 6-9 months of age.
Severe Thalassemia required transfusions. There is a danger of iron overload and transmission of infectious disease.
Alfa and beta Thalassemia minor require no treatment
Lab finding:
Hb electrophoresis :
Hb in Alfa Thalassemia minor ( 1 “ and 2- gene deletions ) = normal
Hb in Alfa Thalassemia ( 3- gene deletion or HBH disease ) = HbH increased
Alfa Thalassemia ( 4- gene deletions ) or Hb Bart™s disease = Hb Bart™s increased
Beta “Thalassemia minor :
increased in HbA2 ( best parameter ) an HbF
MCV/RBC ration : < 13
Reticulocyte count : < 2 % in mild thal; > 3 % in severe types
Key findings : basophilic stippling ( indicates problem with Hb synthesis ),
Target cells ( an excellent marker of Hb disorders )
Tear drop cells ( possibly due to removal of excess globins chains by macrophages),
Alpha “globins chains in severe Beta “Thalassemia ( Cooley™s anemia; inclusions are toxic leading to hemolysis )
PATHOGENESIS
Decreased Hb synthesis
Alfa- Thalassemia : Asians , Blacks ( decreased Alfa “globin chain synthesis on chromosome 16 )
Beta “Thalassemia : Blacks, Italians, Greeks ( decreased beta “globin chains on chromosome 11 ( point mutation producing splicing defect most common )
Increased synthesis of HbA2 and F.
Beta Thalassemia : Minor and Major ( Cooley's anemia-hemolytic component )
CAUSES:
Autosomal recessive
1-gene deletion : silent carrier
2 gene deletion : Alfa Thalassemia trait
3 “gene deletion : HbH disease, Hemolytic anemia
4-gene deletion :
Hb Bart™s disease. Incompatibility with life. Spontaneous abortion, increased risk of molar disease ( hydatiform mole and choriocarcinoma
EVAL/TREATMENT
Severe Thalassemia do not manifest at birth.
Fist manifestation occur at 6-9 months of age.
Severe Thalassemia required transfusions. There is a danger of iron overload and transmission of infectious disease.
Alfa and beta Thalassemia minor require no treatment
Lab finding:
Hb electrophoresis :
Hb in Alfa Thalassemia minor ( 1 “ and 2- gene deletions ) = normal
Hb in Alfa Thalassemia ( 3- gene deletion or HBH disease ) = HbH increased
Alfa Thalassemia ( 4- gene deletions ) or Hb Bart™s disease = Hb Bart™s increased
Beta “Thalassemia minor :
increased in HbA2 ( best parameter ) an HbF
MCV/RBC ration : < 13