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19 Cards in this Set

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What is hemolytic anemia?
A hemolytic state occurs when the RBC survival is shortened. Anemia when rate of hemolysis faster than bone marrow can compensate.
Consequences of intracorpuscular membrane defects:
Decreased membrane stability
decreased cellular flexibility
loss of membrane
loss of biconcave shape
What is Hereditary Spherocytosis?
genetic disorder of RBCs that make them prone to hemolysis.
RBCs have decreased S:V ratio.
Spherocytes on the blood smear are diagnostic of spherocytosis.
what are the possible defected proteins in Hereditary Speherocytosis?
spectrin*
ankyrin*
band 3
palladin

*most common defects
Pathophysiology of HS
cytoskeleton uncouples from lipid bilayer. RBCs become trapped in & conditioned in spleen.
Characteristics of the spherocytes in HS
Decreased surface area:volume
increased cytoplasmic viscocity: decreased deformibility
membrane has decrease in total lipids: no proteins to hold lipids in place
abnormally permeable to Na+
easily trapped in spleen
clinical features of HS
1. jaudice, anemia, splenomegaly
2. all ages affected
3. variable hemolytic state: severity depends on ability to compensate
4. gallstones in older, untreated pts.
Lab findings of HS
1. mild anemia
2. INCREASED retic count RPI>2
3. sphero, polychrom, anis, poik
4. MCV & MCH usually NORMAL
5. MCHC >36% (HYPERCHROMIC)
6. increased bilirubin, osmotic fragility
7. negative antiglobluin test
Therapy of HS
splenectomy
What is Hereditary Elliptocytosis (HE)?
group of disorders characterized by large #'s of elliptical RBCs in peripheral blood.
etiology & pathophysiology of HE
deficiency in band 4.1
decreased assoc. of spectrin dimers to tetramers caused by abnormal spectrin chains
abnormal interactions among several membrane proteins
other molecular abnormalities
interesting clinical features of HE
90% of patients have no clinical symptoms
10% of patients have chronic hemolytic state
lab findings of HE
variable depending on subgroup
ELLIPTOCYTOSIS ALWAYS PRESENT
What is hereditary pyropoikilocytosis (HPP)?
rare hemolytic anemia characterized by thermal sensitivty of RBCs. Variant of HE
Hallmarks of HPP
1. bizarre micropoikilocytes in which red cell budding, microspherocytes & elliptocytes are present
2. increased thermal sensitivity of RBC membrane
3. autosomal recessive inheritance
etiology/pathophysiology of HPP
horizontal, vertical defects combine to cause membrane instability.
-spectrin self-association (horizontal) impaired
-spectrin deficiency (vertical) impaired
Clinical features of HPP
SEVERE hemolytic anemia
evident in infancy or early childhood
Lab findings of HPP
low MCV - many fragmented cells
striking morphologic abnormalities on blood smear
(elliptocytes, fragments, spherocytes)
increased osmotic fragility
Therapy for HPP
splenectomy. if it is severe, transfusions may be necessary