Adult sickle cell disease Flashcards
HbA structure
2 alpha chains
2 beta chains
HbA2 structure
2 alpha groups
2 delta groups
HbF structure
2 alpha chains
2 gamma chains
Normal Hb
HbA
What is sickle cell disease
Inheritance of two abnormal Hb at least one of which is an S
What is sickle cell anemia
inheritance of 2 S hemoglobins
sickle cell trait is said for those who are
AS
Method of inhertance of sickle cell dx
autosomal recessive
Pathophysiology of sickle cell anemia
replacement of adenine with thymine leading to insertion of valine instead of glutamic acid on position 6 of beta globulin chain–>abnormal amino acid–> abnormal protein.
Abnormal Hb formed is insoluble and forms crystals at low oxygen tension.
Rbcs have to deform to fold on itself to pass through narrow capillary microvasculature which has a low oxygen tension
At capillary lumen, low oxygen tension causes deformed RBC to crystallize and not modify its shape—> blockage of microcirculation–>infarcts
Most common sickle cell state
steady state punctuated with crisis
Different presentations of sickle cell disease
variable
steady state punctuated with crisis
chronic hemolytic anemia
end organ damage
crises in sickle cell
has a sudden onset
2 types of crises occur in sickle cell patients
vaso occlusive crisis- hands foot syndrome; bones and joints
hematological crisis - aplastic anemia by parvovirus B19;splenic sequestration
adult triggers
are occasional
children triggers are caused by
infections
