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Terms in this set (83)

- beta 6 Glu --> Val
- substitution of valine for glutamic acid in the 6th amino acid position of the beta globin chain
- deoxy HbS polymerizes leading to sickling of cells
- autosomal recessive
- 30% western and central Africa
- 1 in 12 AA carry trait
- 1 in 500 AA have disease
- 1 in 1000-5000 hispanic have
- carriers produce more than 50% HbA and 25-25% HbS
- sticky hydrophobic patch (deoxy HbS binds another HbS called nucleation) (become strands of HbS)
- leads to hypoxia and futher deoxygenates HbS and causes more sickling
- reoxygenation can cause them to return to normal biconcave shape (may be irreversibility sickled cells)
- infarcts: infection, dehydration, hypoxia (high alt, operations, cold, exercise), drug/alcohol, pregnancy, stress
- infarcts in: bones, lungs, spleen, brain, spinal cord, liver, penis, eyes, kidneys, ulcer in lower leg
- painful crisis syndromes: acute chest syndrome (blood, scarred lung, most common death in adults), priaprism (constant erection, 40% men), immune system weakened, strokes (children)
- treatment: avoiding painful crises, detect infections (causing these crises), eat balances diets (extra vitamins, folic acid, support hyperactive BM)
- painful crisis treatment: bed rest, liquids to increase blood volume, normal RBC transfusion to reduce RBC's high in HbS
- therapy: stimulate HbF using hydroxyurea (inhibits HbS polymerization), replace defective gene (bone marrow transplant)
- lose spleen (most cases it gets larger, here it's been in overdrive since childhood so infarcts off spleen)