Thalassemia Flashcards
at what level of MCV should you think about thalassemia major
70
Hemoglobin S, beta-thalassemia electrophoresis
hemoglobin s + hemoglobin A (with major there is severely decreased beta-globin production)
Hemoglobin E pathophys
Point mutation in the Beta-globin gene that causes decreased production of beta-globin and results in a thalassemia-like syndrome
Hemoglobin E clinical features
mild anemia + mild splenomegaly + no acute pain events
Alpha-thalassemia trait lab features
chronic mild microcytic anemia (Hgb around 10)
Alpha-thalassemia trait electrophoresis
Normal electrophoresis pattern (decreased hemoglobin A levels, but migrate in a normal pattern on electrophoresis)
Beta-thalassemia minor clinical features
chronic microcytic anemia
Beta-thalassemia minor electrophoresis pattern
- Increased amounts of hemoglobin A2 (excess alpha chains link with other chains to produce increased amounts)
- no HbA1
electrophoresis pattern in beta thalassemia major
- increased HbA2 (body compensates by producing more HbA2 which is composed of delta subunits not beta)
- reduced HbA
- increased HbF
what is the normal hemoglobin protein structure
HbA (adult hemoglobin), which has 2 alpha and 2 beta subunits
what is hemoglobin A2?
Normal variant of hemoglobin A, consisting of 2 alpha and 2 delta chains, which is found at low levels in normal human blood
Nomenclature for beta thalassemia major
B0/B0
Nomenclature for beta thalassemia intermedia
B+/B0
Nomenclature for beta thalassemia minor
B+/B+
HbE/Beta thalassemia clinical features
- Asian people
Hemoglobin E disease – homozygotes clinical features
- minimal anemia
- target cells
HbS- alpha thalassemia clinical features
- less severe than sickle cell-beta thalassemia (alpha thalassemia leads to beta globin production, which are less toxic to RBC membrane than alpha globin chairs)
Unique features of hemoglobin SC disease
- milder clinical course than sickle cell BUT all the same complications has hemoglobin SS
- more significant retinopathy, cerebral fate embolism, and ischemic necrosis of bone and priapism (HbC leads to dehydration of the SC red cell, leading to serious clinical sequelae)
Hemoglobin C disease clinical features
- moderate *normocytic anemia
- component of hemolytic anemia
- splenomegaly
Sickle cell variant that has similar phenotype to sickle cell disease
- hgbS-beta thalassemia (they have similar acute pain episode frequency and are at similar risk of ACS)
Pathophys of hemoglobin C disease
point mutation in beta globin chain (substitution of glutamic acid for lysine)
End organ liver damage more common in thalassemia than in SCD
Endocrinopathy and cardiomyopathy (sickle cell patients tend to just develop liver iron loading)
Prevention of neonatal hemochromatosis
Weekly IVIG