Thalassemia Flashcards
What is usually the MCV in Thalassemia ??
< 80
What are the genetics of thalassemia ?
Autosomal Recessive
Heme consists of ?
Iron + Protoporphyrin
What is the main problem in Thalassemia ?
the Globin
What is Alpha thalassemia trait ?
1 locus deleted, asymptomatic
How many loci are deleted in Alpha thalassemia minor ?
2 loci deleted, asymptomatic
maybe can have very mild microcytic anemia
Alpha thalassemia with 3 loci deleted, how does it affect beta chains ?
Beta chains are unpaired, forming Beta-4 tetramers
they are present in the RBCs but not in the bone marrow
What is Hemoglobin barts, and how many alpha loci are deleted ?
4 alpha loci deleted
Has a very high affinity to oxygen, impossible to deliever oxygen to tissues.
what can be a consequence of Hemoglobin barts ?
Hydrops fetalis
death in utero
What is the most accurate test to diagnose alpha thalassemia ?
Genetic studies
what is usually the cause for mild anemia in alpha thalassemia ?
Splicing defects
what is usually the etyology for severe anemia in alpha thalassemia ?
non sense point mutation
stop codon
Clinical fetures of Beta-thalassemia intermedia ?
Variable anemia that may require transfusions during periods of stress
do we have production of beta-globin in the Beta thalassemia major ?
NO, zero production
hemotetramers effect on bone marrow ? (beta thalassemia major)
Ineffective erythropoiesis
RBC die eralier, before being released
Hemotetramers effect on kidney ? (beta thalassemia major)
Hemolytic anemia and increased production of EPO
what sign can we see on skull and jaw with beta-thalassemia major ?
- Crew cut skull
- Chipmunk facies
because of medullary erythroid hyperplasia
what happends to RBC count in Thalassemia ?
Increases
what cells we can see occasionaly in Alpha thalassemias ?
- Tear drop cells
- Target cells
What cells can we see in Beta-thalassemia in a consistent manner ?
Tear drop and target cells
what are the levels of HbA2 in beta-thalassemia minor/intermedia/major ?
High
what are the levels of HbF in beta-thalassemia minor ?
normal-to-low elevations of HbF
May be normal in some patients with thalassemia minor !!!
What are the levels of bilirubin in Beta-thal Major ?
we get Unconjugated Hyperbilirubinemia
Because we have hemolysis (from the protoporphyrin)
What are the levels of reticulocytes in Beta-thal Major ?
Increased
do you give Iron in the ttt of Thalassemia ?
No
It will lead to iron overload
What is the ttt for thalassemia ?
Blood transfusion
How do we manage iron overload ?
Chelation
(Defroxamine)
Beta thalassemia: most commonly seen in people of
Mediterranean descent
Alpha thalassemia: most commonly seen in people of
Asian and African descent
Thalassemia provides partial resistance against
Malaria
Hb Bart consists of
Four γ-chains (γ-tetramers)
In a normal cell, the β-globin chains are coded by a total of
two alleles
What causes sickle cell beta-thalassemia ?
a combination of one defective β-globin allele and one defective HbS allele
What is the cause of the anemia in Thalassemia ?
Combination of inefficient erythropoiesis and increased hemolysis.
What leads to bone marrow hyperplasia and skeletal deformities in thalassemia?
The increased EPO
Because of the anemia
what type of anemia do we have in the major forms of beta thalassemia?
Hemolytic anemia
That often requires transfusions
When do we see the signs of HbH disease?
Usually neonatal period
characterized by mild to moderate anemia, hepatosplenomegaly, and jaundice.
