Hematology - Hemolytic Anemias

Front 1

What is hemolytic anemia?

Back 1

A hemolytic state occurs when the RBC survival is shortened. Anemia when rate of hemolysis faster than bone marrow can compensate.

Front 2

Consequences of intracorpuscular membrane defects:

Back 2

Decreased membrane stability
decreased cellular flexibility
loss of membrane
loss of biconcave shape

Front 3

What is Hereditary Spherocytosis?

Back 3

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.

Front 4

what are the possible defected proteins in Hereditary Speherocytosis?

Back 4

spectrin*
ankyrin*
band 3
palladin

*most common defects

Front 5

Pathophysiology of HS

Back 5

cytoskeleton uncouples from lipid bilayer. RBCs become trapped in & conditioned in spleen.

Front 6

Characteristics of the spherocytes in HS

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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

Front 7

clinical features of HS

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1. jaudice, anemia, splenomegaly
2. all ages affected
3. variable hemolytic state: severity depends on ability to compensate
4. gallstones in older, untreated pts.

Front 8

Lab findings of HS

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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

Front 9

Therapy of HS

Back 9

splenectomy

Front 10

What is Hereditary Elliptocytosis (HE)?

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group of disorders characterized by large #'s of elliptical RBCs in peripheral blood.

Front 11

etiology & pathophysiology of HE

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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

Front 12

interesting clinical features of HE

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90% of patients have no clinical symptoms
10% of patients have chronic hemolytic state

Front 13

lab findings of HE

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variable depending on subgroup
ELLIPTOCYTOSIS ALWAYS PRESENT

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What is hereditary pyropoikilocytosis (HPP)?

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rare hemolytic anemia characterized by thermal sensitivty of RBCs. Variant of HE

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Hallmarks of HPP

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1. bizarre micropoikilocytes in which red cell budding, microspherocytes & elliptocytes are present
2. increased thermal sensitivity of RBC membrane
3. autosomal recessive inheritance

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etiology/pathophysiology of HPP

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horizontal, vertical defects combine to cause membrane instability.
-spectrin self-association (horizontal) impaired
-spectrin deficiency (vertical) impaired

Front 17

Clinical features of HPP

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SEVERE hemolytic anemia
evident in infancy or early childhood

Front 18

Lab findings of HPP

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low MCV - many fragmented cells
striking morphologic abnormalities on blood smear
(elliptocytes, fragments, spherocytes)
increased osmotic fragility

Front 19

Therapy for HPP

Back 19

splenectomy. if it is severe, transfusions may be necessary