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Clinical Hematology > Test 5 Review sheet > Flashcards

Test 5 Review sheet Flashcards

(68 cards)

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1
Q

What type of effects/defects are present in qualitative hemoglobinopathies?

A

Structural defects

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2
Q

What condition is the most common form of hemoglobinopathies?

A

Sickle cell diseases

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3
Q

What is Vasoocclusive event

A

hallmark features of sickle cell disease, accounting for most hospital and emergency department visits

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4
Q

What ethnic group doesn’t express sickle cell diseases?

A

Scandinavia

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5
Q

Factors that make blood more viscous?

A

when polymers are formed and sickle cells are created

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6
Q

What is the effect of blood viscosity

A

reduced blood flow

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7
Q

How does blood become acidic?

A

prolongs exposure of the sickle cells to a hypoxic environment (decreased oxygen tension)

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8
Q

What occurs post-reduction of pH?

A

reduction in pH occurs and 2,3-biphosphoglycerate levels

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9
Q

Characterize sickle cell crisis in a blood smear

A

target cells, Howell-Jolly bodies, and an elevated white count (leukocytosis)

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10
Q

What confers resistance against P. Falciparum?

A

Sickle cell trait (heterozygosity for hemoglobin S [Hb S])

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11
Q

Where is this abnormal hemoglobin prevelant?

A

areas where this form of malaria is endemic

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12
Q

What globin genes are abnormal in homozygous Hb S?

A

Beta-globin genes are abnormal in homozygous Hb S. Hb A is not present unless the patient has received a red cell transfusion

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13
Q

Characterize Hb S to Hb A

A

Hb S is less soluble than normal Hb A, the reticulocyte count is elevated, and patients usually have a high Hb F

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14
Q

What is the tube solubility test of Sickle cell trait and Hb SS

A

The tube solubility test is positive

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15
Q

How can you differentiate b/n sickle cell trait and sickle cell anemia?

A

hemoglobin electrophoresis is the best test to differentiate the 2
. Sickle cell trait should have roughly 40% Hb S and 55% Hb A
sickle cell anemia should have predominantly Hb S with a variably increased Hb F and no Hb A

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16
Q

What other hemoglobin can appear on an alkaline hemoglobin electrophoresis?

A

Hb D

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17
Q

What would precipitate sickling of sickle cell anemia?

A

Hb S forms insoluble polymers when the oxygen saturation is low

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18
Q

What red cell morphology is present in sickle cell trait?

A

Target cells are present

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19
Q

What conditions show target cells? what conditions don’t?

A

They are present in Hb C, Hb E, and sickle cell. not seen in hereditary spherocytosis

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20
Q

The presence of what hemoglobin gives a positive tube solubility?

A

presence of Hb S

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21
Q

What hemoglobin type is elevated in Hb M?

A

Methemoglobin is elevated, 30% to 50% methemoglobin (Fe3+)

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22
Q

What may be present but not visible in Hb M?

A

Heinz bodies may be present, but they are not visible with a Wright stain

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23
Q

How is methemoglobin formed?

A

The amino acid substitutions found in the various Hb Ms cause heme iron to autooxidize, forming methemoglobin

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24
Q

How are Heinz bodies formed?

A

when hemoglobin is unstable and precipitates

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25
What occurs during hemoglobin O2 high affinity?
less oxygen is released to tissue, leads to increase erythropoietin and make more red cells
26
Characterize point mutation
Replacement of one nucleotide in the normal gene with a different nucleotide
27
How can point mutation affect the protein's function?
results in a different amino acid and can affect the protein’s function
28
Which hemoglobin are seen on cellulose acetate?
Hb S, Hb A, Hb F, and Hb A2
29
Where do you see Hb A?
transfused red cells
30
What are Hb A2 and F
normal hemoglobins
31
Where do you see Hb S
patients with homozygous Hb S
32
In what ethnicity can you find Hb E?
Southeast Asian populations
33
What are the lab results for Hb E?
migrates with Hb C on cellulose acetate alkaline electrophoresis. The MCV is low and target cells are present in this trait Because Hb A is also present, this patient probably has Hb E trait
34
What is thalassemia?
a varied group of disorders in which the synthesis of a normal globin chain is reduced or absent. globin chains that are made are normal in amino acid structure
35
What are the concentrations of hemoglobins and what kind of globin chains are they made of?
Hb A: 96%, made of a2b2 Hb A2: 2%, made of a2d2 Hb F: 2%, a2g2
36
What globin chains is deficient/absent in beta thalassemia?
Beta globin chain is decreased to absent
37
What globin chain is normal in beta thalassemia?
alpha globin chain synthesis is normal
38
What population doesn't require beta chains?
Infants up until approximately 6 months of age have an elevated Hb F that does not require beta chains
39
What is the primary mechanism that leads to anemia in thalassemia?
An imbalance exists in the rate of globin chain synthesis in the thalassemias
40
what damages the red cell?
A build-up of the globin chain is produced in excess
41
Characterize the bone marrow in thalassemia
Erythroid hyperplasia is present
42
What group of disorders are thalassemia?
a heterogeneous group of disorders that range from asymptomatic (benign) to death (incompatible with life)
43
State the morphology of RBCs in beta thalassemia major and minor
Minor: Basophilic stippling is seen in red cell Major: Microcytes, hypochromia, and target cells (however present in minor as well)
44
What can differentiate beta thalassemia major and minor?
Clinical findings, hemoglobin concentration, and presence of Hb A
45
What is the primary hemoglobin in homozygous beta-thalassemia?
Hb F, with the remainder being Hb A2.
46
What hemoglobin is not present in homozygous beta-thalassemia?
Hb A exists, because no beta globin chains are made
47
What cannot be produced with missing alpha globin chains?
Hb F
48
What hemoglobin is present at birth in all forms of alpha thalassemia?
Barts (gamma 4) hemoglobin is present at birth
49
What is not present in all forms of alpha thalassemia?
Hb H inclusions, anemia, and microcytic red cells
50
How does hemoglobin H disease occur?
three genes are missing for alpha globin chain synthesis excess of beta chains (b4), which is named Hb H, is present and easily detectable
51
What kind of anemia is present with Hb H disease?
mild to moderate anemia
52
In what ethnicity is Hb H disease prevelent?
Asian ethnicity
53
What hemoglobin require alpha chains?
All normal hemoglobins (A, A2, and F)
54
What is the predominant hemoglobin in the uterus?
the predominant hemoglobin will be Hb Barts (g4)
55
Characterize Hb Barts?
a high-oxygen-affinity hemoglobin and thus is not effective in reversible oxygen transport
56
What is the predominant hemoglobin up until the 3rd trimester?
Hb Portland is the primary hemoglobin
57
Characterize a patient with hemoglobinopathy for Hb S?
patient will not have any normal beta chains to combine with alpha chains and form Hb A patient will have primarily Hb S, with an elevated Hb F, which is the same pattern seen in homozygous Hb S (i.e., sickle cell anemia) red cells will be microcytic
58
What tests are useful for differentiating thalassemia?
Hemoglobin electrophoresis CBC results and clinical findings (could vary)
59
What is the CBC result for a thalassemia trait?
The red blood cell (RBC) count is relatively high with a low MCV in thalassemia trait
60
What is the iron deficiency result for a thalassemia trait?
MCV can be low, but the red count is also low
61
Characterize Hb Barts
composed of four gamma chains It is present at birth in all forms of alpha-thalassemia, even the silent carrier state (one gene deletion)
62
The Beta+ gene locus decreases what?
beta Globin chain synthesis is decreased
63
What is the treatment for patients with beta thalassemia major?
massive red cell transfusion therapy
64
What is the consequence for treatment of beta thalassemia major?
build up of iron in the body from all the transfused RBCs because the body has no mechanism for excreting iron
65
Characterize Hb Lepore
delta-beta fusion globin chain with decreased synthesis of the chain Heterozygotes have a clinical course similar to that of beta-thalassemia minor.
66
In which ethnicity is Hb E prevalent?
Southeast Asia
67
Why is seperating Hb A2 and Hb F important
important to do when working up patients with possible thalassemic syndromes
68
What test is able to separate and quantify Hb A2 and Hb F?
High-performance liquid chromatography

Clinical Hematology (6 decks)

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