HEMA LEC - Thalassemias Flashcards
group of inherited disorders causing genetic mutations that reduce or prevent synthesis of one or more globin chain
thalassemis
thalassemia is characterized by __ rbcs
microcytic/hypochromic
first described children with anemia
thomas cooley and pearl lee
nonspecific or general classif of thal
severe course of thalasemia
either no alpha or beta chain produced
homozygous
nonspecific or general classif of thal
milder anemia; carriers
heterozygous
defects that cause a decrease or absent production of particular globin [3]
point mutation
small insertions or deletions
large deletions
specific thal categories
alpha thalassemia
beta thalassemia
premature death of rbc precurosrs in BM
ineffective erythropoiesis
anemia in thalassemia is due to 2 main components
ineffective erythropoiesis
extravascular hemolysis in RES esp spleen
imperfect extravascular hemolysis produces __
nucRBCs and tear drop rbcs
mildest form of B thal
silent carrier state
heterozygous disorder resulting in mild hypochromic, microcytic, hemolytic anemia
B thalassemia minor
severity lies between major and minor
B thalassemia intermedia
homozygous disorder resulting in severe life long transfusion-dependent hemolytic anemia
B thalassemia major
thalassemias are Named according to the ?
chain with reduced or absent synthesis
Decreased or absent synthesis of one of the globin gene
chains not only leads to decreased but also ________

in imbalance in the alpha/beta chain ratio hb
production
third component that contributes to the severity of anemia that may also worsen the anemia
splenomegaly
how may splenomegaly worsen anemia
bec of 2 components:
1) increased sequestration
2) increased plasma volume caused by splenomegaly (dilutional)
____occurs, which also contributes for the splenomegaly,
Extramedullary erythropoiesis
Are various heterozygous (from one parent) β gene mutations that produce only small decrease in production of β globin chains.
•   Patients have nearly normal alpha/beta chain ratio and no hematologic abnormalities.
• Have normal levels of HbA2
Silent Carrier State for β-Thalassemia
Decreased rate of synthesis of one of the beta chains; other beta chain normal
β Thalassemia Minor (Trait)
• Caused by heterozygous (from one parent) mutations that affect β globin synthesis.
β Thalassemia Minor (Trait)
• β Chains production and thus Hb-A production is more reduced than the silent carrier Hb-A.
β Thalassemia Minor (Trait)
•       Have one normal β gene and one mutated β gene.
β Thalassemia Minor (Trait)
• Usually presents as mild, asymptomatic hemolytic anemia unless patient in under stress such as pregnancy, infection, or folic acid deficiency.
β Thalassemia Minor (Trait) or B thalassemia Intermedia
anemia usually hypochromic and microcytic w/ slight aniso and poik, including target cells and elliptocytes; may also see basophilic stippling
β Thalassemia Minor (Trait)
rarely see hepatomegaly or splenomegaly
β Thalassemia Minor (Trait)
have high Hb A2 levels (3.6-8.0%) and normal to slightly elevated HbF levels
β Thalassemia Minor (Trait)
B thalassemia that normally requires no treatment
β Thalassemia Minor (Trait)
confused with IDA
β Thalassemia Minor (Trait)
uses Mentzer index
β Thalassemia Minor (Trait)
markedly decrease rate of synthesis or absence of both beta chains results in an excess of alpha chains, no Hgb A can be produced; compensate with up to 90% Hgb F
β Thalassemia Major/Cooley’s Anemia
Excess alpha chains precipitate on the RBC membrane, form Heinz bodies, and cause rigidity; destroyed in the bone marrow or removed by the spleen
β Thalassemia Major/Cooley’s Anemia
Symptomatic by 6 months of age; hepatosplenomegaly, stunted growth, jaundice, prominent facial bones (Esp cheek and jaw); iron overload from RBC destruction and multiple transfusions cause organ failure
β Thalassemia Major/Cooley’s Anemia
profound anemia stimulates an increase in EPO production by kidneys and results in massive but ineffective erythroid hyperplasia
β Thalassemia Major/Cooley’s Anemia
marked bone changes and deformities occur due to massive BM expansion
β Thalassemia Major/Cooley’s Anemia
thalassemia major life expectancy
Without regular transfusion –
Less than 10 years
thalassemia major life expectancy
With regular transfusion and no or poor iron chelation
Less than 25 years
thalassemia major life expectancy
With regular transfusion and good iron chelation
40 years, or longer??
iron chelator
desferoxamine
Have varying symptoms of anemia, jaundice, splenomegaly and hepatomegaly
B thalassemia intermedia
have significant increase in bilirubin levels
B thalassemia intermedia
anemia usually becomes worse with infections, pregnancy or folic acid deficiency
β Thalassemia Minor (Trait) or B thalassemia intermedie
MAY become transfusion dependent
B thalassemia intermedia
tend to develop iron overloads as a result of increased gastrointestinal absorption
B thalassemia intermedia
usually survive into adulthood
B thalassemia intermedia
