Sickle Cell Flashcards
What CBC results will be seen bc of the hemolytic anemia?
anemia, high retic count, increased RDW, sometimes increased WBCs and platelets
What is normal progression of hemoglobins on the beta chain from fetus to adult?
epsilon, gamma, delta, beta
What is Hydroxyurea?
an oral chemo agent
_____ occurs in a person with one sickle cell gene and one normal gene.
Sickle cell trait
_____ occurs in persons who have two abnormal β-globin genes; at least one of these genes has the sickle mutation.
Sickle cell disease
What is the treatment for iron overload?
a chelation agent
What is the acute, severe swelling of the hands and feet, usually in sickle cell infants called?
hand-foot syndrome
How is sickle cell inherited?
auto. recessive
Name 3 complications of hemolysis in sickle cell.
1) aplastic crisis 2) growth retardation or delay 3) bilirubin gallstones
What can occur after several transfusions?
iron overload
What findings will be seen in Sickle Cell on the peripheral smear?
sickle forms, schistocytes, polychromasia
What are the 3 major treatments of sickle cell?
1) bone marrow transplant 2) Hydroxyurea therapy 3) transfusion
Where are the hemoglobin beta genes located?
chromosome 11
What does normal hemoglobin A2 consist of?
alpha2-delta2
What is the predominant hemoglobin after age 2?
HbA
When deoxygenated, sickle hemoglobin polymerizes into _____ which distort the shape of the RBC into a “sickle form.”
14-strand helical fibers
How long do sickle RBCs last in circulation?
20 days
Retinal vessel damage can lead to ____ and ____.
retinal detachment; blindness
Sickle cell disease occurs in persons who have two abnormal β-globin genes; at least one of these genes has _____.
the sickle mutation
What is normal progression of hemoglobins on the alpha chain from fetus to adult?
zeta, alpha
What is acute chest syndrome?
sickle RBCs become trapped in the lungs- damage endothelium- fluid leaks in- can’t breathe
What abnormal chemistry findings will be seen in sickle cell anemia?
increased bilirubin, LDH, AST
Why do skin ulcers occur in sickle cell anemic?
microvascular ischemia and poor healing
When large numbers of sickle RBCs become abruptly trapped in the spleen, causing severe anemia and shock, ______ has occurred.
splenic sequestration
Nearly all patients with sickle cell anemia (HbSS) chronically occlude the spleen’s microcirculation, resulting in “autoinfarction” (destruction) of the spleen by the age of ___.
5
What are the beta globin genes in sickle cell disease?
HbSS
In what locations can sickles be formed in sickle cell train?
renal medulla
How is sickle cell diagnosed?
gel electrophoresis (separation) of the hemoglobins
What is sickle cell crisis?
when a stressor, coupled with BV damage and constriction, causes sickling and pain
What does normal hemoglobin A1 consist of?
alpha2-beta2
Name locations that sickle cells tend to adhere and cause vascular occlusion.
1) spleen 2) CNS 3) lungs 4) kidney 5) retina 6) femoral and humeral head 7) ankle skin (ulcers)
What is strain on the R side of the heart called?
cor pulmonale
What is splenic sequestration?
when large numbers of sickle RBCs become abruptly trapped in the spleen, causing severe anemia and shock
Why is Hydroxyurea used to treat sickle cell pts?
fetal hemoglobin produced interferes with sickle hemoglobin polymerization
What does normal hemoglobin F consist of?
alpha2-gamma2
What is priapism?
sustained, painful erections
What is hand-foot syndrome?
acute, severe swelling of the hands and feet, usually in sickle cell infants
What is a limitation for bone transplants in sickle cell patients?
finding a match- less than 20% have a donor avail
What is the average lifespan of a sickle cell pt?
50-60
How much HbF is seen at a normal birth?
60-90%
What does Hydroxyurea do?
it induces production of fetal hemoglobin in persons older than 12 mos
Sickled RBCs cause damage to the lung microvasculature, leading to _____.
pulmonary arterial hypertension (PAH)
Why do sickle cells have a propensity to adhere to one another?
membrane injury, retention of surface adhesion molecules
How much HbA is seen at a normal birth?
10-40%
What are the beta globin genes in sickle cell trait?
HbAS
How are the kidneys affected by sickle cells?
tubules damaged, leading to inability to concentrate urine (to prevent dehydration); glomerular damage
When ______, sickle hemoglobin polymerizes into 14-strand helical fibers which distort the shape of the RBC into a “sickle form.”
deoxygenated
Sickle cell disease occurs in persons who have two abnormal _____; at least one of these genes has the sickle mutation.
β-globin genes
What is aplastic crisis?
a sudden drop in hemoglobin from compromised bone marrow
When are the RBCs more likely to sickle?
hypoxia, dehydration, inflammation, infection, or other stresses
What causes aplastic crisis in children?
Parvovirus B19
What is the predominant hemoglobin in sickle cell trait?
hemoglobin A
In what instances can sickles be formed in sickle cell trait?
exertion at altitude coupled with dehydration
How do bone infactions occur in sickle cell?
chronic ischemia leads to necrosis
How much HbA2 is seen at a normal birth?
less than 1%
Nearly all patients with sickle cell anemia (HbSS) chronically occlude the spleen’s microcirculation, resulting in “_______” (destruction) of the spleen by the age of 5.
autoinfarction
Nearly all patients with sickle cell anemia (HbSS) chronically occlude the spleen’s ______, resulting in “autoinfarction” (destruction) of the spleen by the age of 5.
microcirculation
What can potentially cure sickle cell disease?
bone marrow transplant
What are the requirements for a bone marrow transplant donor?
HLA-matched, full sibling, unaffected
Where does iron overload affect the body?
liver and heart
Sickle cell trait occurs in a person with _____.
one sickle cell gene and one normal gene
What are the 3 main sickle cell clinical manifestations?
1) chronic hemolytic anemia 2) chronic RBC adhesion/vascular occlusion 3) acute RBC adhesion/vascular occulusion
What is a risk patients with sickle cell face because of RBCs damaging the CNS?
stroke
Where are the hemoglobin alpha genes located?
chromosome 16
What finding is characteristic of aplastic crisis?
low retic count
