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Hematology 1 > (F) L1: RBC Disorders (Part 2: Abnormalities in the RBC Membrane) > Flashcards

(F) L1: RBC Disorders (Part 2: Abnormalities in the RBC Membrane) Flashcards

1
Q
  • The RBCs have a defect in the membrane proteins of ankyrin, band 3, a-spectrin, b-spectrin, and protein 4.2 (deficiencies)
  • The cell becomes spherical and fragile leading to their premature destruction in the spleen causing anemia
  • In a hypotonic solution, the water tends to enter the RBC through osmosis (reduced surface area and spherical shape)
A

Hereditary Spherocytosis

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2
Q

In the skeletal proteins of RBCs that maintain its biconcave shape, what are the primary proteins?

Clue: 2 answers

A
  1. Alpha-spectrin
  2. Beta-spectrin
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3
Q

The environment of this organ includes low pH, ATP, and glucose which promotes RBC swelling and eventual bursting

A

Spleen

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4
Q

In Hereditary Spherocytosis and Elliptocytosis, RBCs are abnormally permeable to what element?

A

Sodium

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5
Q

Hereditary Spherocytosis Lab Findings:
1. What is the normal MCHC range?
2. What is the increased (abnormal) MCHC range?

A
  1. 31-37 g/dL
  2. 35-38 g/dL
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6
Q
  • The RBCs have an elliptical and oval shape due to the mutation in proteins
  • Deficient for proteins a-spectrin, b-spectrin, and protein 4.1 (reduced flexibility)
  • In a hypotonic solution, it is more rigid and less flexible than the normal biconcave RBC (are more distended and may undergo hemolysis/fragmentation)
  • The RBCs are relatively more stable in an osmotic environment (less prone to hemolysis in both isotonic and hypertonic solutions)
A

Hereditary Elliptocytosis

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7
Q

TOF: Hereditary Spherocytosis is less severe than Hereditary Elliptocytosis

A

False (reverse)

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8
Q

Inheritance patterns:
1. Hereditary Spherocytosis
2. Hereditary Elliptocytosis

A. Autosomal Dominant
B. Autosomal Recessive
C. X-linked Dominant
D. X-linked Recessive

A

BOTH are A. Autosomal Dominant

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9
Q
  1. Disturbs vertical membrane interactions between transmembrane proteins underlying cytoskeleton
  2. Disturbs horizontal membrane interactions in the cytoskeleton

A. Hereditary Spherocytosis
B. Hereditary Elliptocytosis

A
  1. A
  2. B
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10
Q

What can be found in the PBS of Hereditary Spherocytosis?

Clue: 2 answers

A
  1. Spherocytes
  2. nRBCs
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11
Q

What can be found in the PBS of Hereditary Elliptocytosis?

A

Elliptocytes

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12
Q

TOF: Hereditary Elliptocytosis has a microcytic normochromic morphology

A

False (normocytic-normochromic)

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13
Q
  • The patient develops autoantibodies against their own RBCs
  • The immune system mistakenly recognizes the body’s own RBCs as foreign invaders and targets them for destruction
A

Autoimmune Hemolytic Anemia

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14
Q
  • This type of Autoimmune Hemolytic Anemia is the most common type and is serologically active at 37ºC
  • It destroys RBCs at body temperature
  • Associated with Systemic Lupus Erythematosus (SLE) and other lymphoproliferative disorders
A

Warm Autoimmune Hemolytic Anemia

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15
Q
  • This type of Autoimmune Hemolytic Anemia is serologically active at 4ºC
  • RBC destruction happens at lower temperatures
  • Associated with Infectious Mononucleosis (IM) and other lymphoproliferative disorders
A

Cold Autoimmune Hemolytic Anemia

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16
Q

2 Types of Cold Autoimmune Hemolytic Anemia

  • The immune system produces cold agglutinins which bind to RBCs at low temperatures
  • It causes RBC clumping and destruction
  • Primarily idiopathic or secondary to Mycoplasma pneumoniae and SLE
A

Cold Agglutinin Syndrome (CAS)

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17
Q

2 Types of Cold Autoimmune Hemolytic Anemia

  • The body produces antibodies that bind to RBCs causing destruction when exposed to cold temperatures
  • Is secondary to a viral infection (e.g. Epstein-Barre virus)
A

Paroxysmal Cold Hemoglobinuria (PCH)

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18
Q

Defective Production of Heme and Globin

A defect in heme synthesis characterized by impaired heme production

A

Porphyria

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19
Q

Defective Production of Heme and Globin

A qualitative globin synthesis defect

A

Hemoglobinopathies

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20
Q

Defective Production of Heme and Globin

A quantitative globin synthesis defect

A

Thalassemia

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21
Q
  • What you call diseases that involve the hemoglobin
  • A collection of disease where there is a point mutation or amino acid substitution within the globin molecule
A

Hemoglobinopathies

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22
Q

Categories of Hemoglobinopathies

Refers to structural defects in the Hgb molecule

A

Qualitative

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23
Q

Categories of Hemoglobinopathies

Refers to the imbalance/underproduction in the number of globin chains

A

Quantitative

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24
Q

The most frequently occurring hemoglobinopathy

A

Beta-hemoglobinopathies

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25
Q

What is the only adult form of hemoglobin that is affected in beta-hemoglobinopathies?

A

HbA1

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26
Q

What are the 4 major groups of hemoglobinopathies?

A
  1. Alpha
  2. Beta
  3. Gamma
  4. Delta
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27
Q

Adult forms of Hgb

  1. 2 alpha and 2 beta
  2. 2 alpha and 2 gamma
  3. 2 alpha and 2 delta

A. HbA1
B. HbA2
C. HbF

A
  1. A. HbA1 (most predominant)
  2. C HbF
  3. B HbA2
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28
Q

All forms of Hgb are made up of how many globin chains?

A

4

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29
Q

Beta-hemoglobinopathies

  • Both beta-genes are mutated
  • HbA1 is absent
  • Abnormal Hgb becomes the predominant type
  • e.g. Sickle Cell Disease (Hb SS) and HbC Disease (Hb CC)
A

Homozygous

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30
Q

Beta-hemoglobinopathies

  • One beta gene is normal while the other is mutated
  • The amount of HbA1 is more or sometimes equal in amount than the abnormal type
  • E.g. Sickle Cell Trait (Hb AS) and Hb C Trait (Hb AC)

Note: A is normal while S and C are mutated

A

Heterozygous

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31
Q

What are the genes that help create beta-globulins?

A

Beta-genes

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32
Q
  • This anemia is formed when glutamic acid is replaced by valine at the 6th position of the beta-chain
  • It also has 2 alpha and 2 beta chains with 146 amino acids
A

Sickle Cell Anemia (Hb S)

Note: The insolubility of deoxygenated Hb S causes the crescent or sickle shape

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33
Q
  1. When oxygenated, Hb S is (soluble/insoluble)
  2. When O2 (drops/rises), sickling happens
A
  1. Soluble (shape is still normal)
  2. Drops
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34
Q

This happens to the sickle cell molecule when it is triggered by low oxygen tension, dehydration, and acidosis

A

Polymerization

35
Q

Peripheral Blood Smear of Sickle Cell

Which cannot be found/observed in the PBS?
1. Drepanocytes
2. nRBCs
3. Polychromasia
4. Poikilocytosis
5. Anisocytosis
6. Macrocytes
7. Howell-Jolly bodies
8. Pappenheimer bodies
9. Erythroid hyperplasia
10. Reticulocytes

A

None, all of these can be found (familiarize yourself)

36
Q

What is abnormal in the following indices during sickle cell anemia?
A. Mean cell volume
B. Mean cell hemoglobin
C. Reticulocyte distribution width

A

C. Reticulocyte distribution width (increased)

Note: Retic. count is increased by 5-20%

37
Q

Sickle Cell Clinical Features

This type of complication will be present in their lifetime for those with sickle cell anemia

A

Severe chronic hemolytic anemia

38
Q

Sickle Cell Clinical Features

This is due to the blockage of trapped sickle cells in one’s capillaries

A

Vaso-occlusive crisis

39
Q
  • This test for Sickle Cell uses blood mixed with sodium metabisulfite (reducing agent) which deoxygenates Hgb
  • Hb S crystallizes after deoxygenation
  • Holly leaf RBCs are often found (positive result)
A

Sodium Metabisulfite Method

40
Q

TOF: You can differentiate between sickle cell trait and sickle cell anemia using the Sodium Metabisulfite Test

A

False (however in sickle cell anemia, sickling happens more rapidly)

41
Q
  • This sickle cell test uses sodium dithionite (reducing agent) and saponin (hemolytic agent) which immediately lyses RBCs
  • The Hb S and sickling Hb will form liquid crystals producing a turbid appearance (positive result)
A

Sodium Dithionite Tube Test

42
Q
  • This test is confirmatory and can further differentiate Hb S from D, G, C, and E
  • The migration distance of different Hgbs are based on their charge and absorption to the agar
A

Hemoglobin Electrophoresis (Citrate Agar)

43
Q

Abnormal Hgb

  • Glutamic acid on the 6th position of the beta chain is replaced by lysine
  • The structural formula is a2b2 6th GLU-LYS
  • The second most abnormal Hgb
A

Hemoglobin C

44
Q

Hgb Crystals related to Hb C

  1. Washington monument-like appearance; protruding from the RBC membrane
  2. Bar of gold appearance found within the RBC membrane

A. Hb CC
B. Hb SC

A
  1. B
  2. A
45
Q

Usually the PBS morphology of this Hgb molecule has the ff.:
- Microspherocytes
- Target cells
- Folded RBCs
- Hb CC crystals

A

Hb C

46
Q

With Hgb C, the ff. are true:
1. RBC indices are (normal/abnormal)
2. Reticulocyte count is slightly (decreased/increased)

A
  1. Normal
  2. Increased
47
Q

Abnormal Hgb

  • The 3rd most common abnormal Hgb
  • The structural formula is a2b2 26th GLU-LYS
A

Hemoglobin E

48
Q

Abnormal Hgb

  1. a2b2 121st GLU-LYS
  2. a2b2 6th GLU-VAL and 73rd ASP-ASN (2 amino acid substitution)
  3. a-68th ASN-LYS b2 (affected alpha chain)

A. Hgb G (Philadelphia)
B. Hgb C (Harlem/Georgetown)
C. Hgb O (Arab)

A
  1. C
  2. B
  3. A
49
Q

Abnormal Hgb

  1. Deletion of 5 amino acids on the beta-chain sequence (91 to 95)
  2. Elongation of the alpha chain and addition of 32 amino acids

A. Hgb Gun Hill
B. Hgb Constant Spring (CS)

A
  1. A
  2. B
50
Q

These are rarely occurring abnormal Hgbs associated with methemoglobinemia and cyanosis

A

M hemoglobins:
- Hb M (Saskatoon)
- Hb M (Milwaukee-1)
- Hb M (Milwaukee-2)

51
Q

Familiarze yourself with the rare abnormal Hgbs associated with increased and decreased oxygen affinity (3 each)

A

Increased:
1. Hb Hiroshima
2. Hb Rainier
3. Hb Bethesda

Decreased:
1. Hb Agenogi
2. Hb Beth Israel
3. Hb Yoshizuka

52
Q
  • An inherited blood disorder that results from the mutation of α-globin chains
  • A deletion of 1, 2, 3, or all of the globin chains
  • Severity is classified based on the number of chains affected
A

Alpha-Thalassemia

53
Q

Alpha-Thalassemia Classifications

  • 1 out of 4 genes are deleted/non-functional
  • Individuals are usually carriers and asymptomatic
  • The 2 alpha globulin genes are functional
  • Genotype: (- a/a a)
A

Silent Carrier State (a-thalassemia)

54
Q

Alpha-Thalassemia Classifications

  • Aka a-thalassemia minor
  • 2 out of 4 genes are deleted/non-functional
  • Individuals may have mild anemia but is often asymptomatic
  • Hgb levels are usually lower but not severely so
  • Manifests as microcytic hypochromic
  • Genotype: (- -/a a) or (- a/ - a)
A

a-thalassemia trait

55
Q

Alpha-Thalassemia Classifications

  • Aka a-thalassemia intermedia
  • There is a deletion of 3 out of 4 alpha genes
  • Leads to moderate to severe anemia with pallor, jaundice, and splenomegaly
  • Manifests as microcytic hypochromic
  • Genotype: (- -/ - a)
A

Hgb H Disease

56
Q

Alpha-Thalassemia Classifications

  • Aka Hgb Bart Syndrome or a-thalassemia major
  • Most severe form resulting in the deletion of 4 genes
  • Leads to severe anemia and fluid accumulation in the body cavities (life-threatening in utero)
  • Most do not survive beyond birth
  • Genotype: (- - / - -)
A

Hgb B Hydrops Fetalis Syndrome

57
Q
  • Characterized by reduced or absent production of beta globin chains
  • Caused by a mutation that affects the ß globin gene complex
A

Beta-Thalassemia

58
Q

Beta-Thalassemia Classifications

  • A mutation in 1 of the 4 beta chains (Hgb production remains normal)
  • Patient has signs and symptoms
  • Genotype: (B-silent/ B)
A

Silent Carrier State (B-thalassemia)

59
Q

Beta-Thalassemia Classifications

  • Aka B-thalassemia minor
  • 1 normal beta gene and 1 affected beta gene
  • There is mild beta globin chain deficiency
  • Patients have slightly lower Hgb level
  • Genotypes: (B+/B) and (B0/B)
A

B-thalassemia trait

60
Q

Beta-Thalassemia Classifications

  • Aka B-thalassemia major
  • Both genes are affected
  • There is severe deficiency of beta globin chains
  • The most severe form typically present in early childhood
  • Genotypes: (B+/B+), (B+/B0), (B+/B), and (B0/B0)
A

Cooley’s Anemia

61
Q

Beta-Thalassemia Classifications

  • Both beta globin chains are affected
  • A moderate reduction of beta globin chain production leading to more pronounced anemia compared to BT minor
  • Manifests as microcytic hypochromic
  • Genotypes: (B-silent/B-silent), (B+/B-silent), and (B0/B-silent)
A

B-thalassemia Intermedia

62
Q
  • A group of genetic disorders that affect the enzymes within the RBCs
  • These play a crucial role in the metabolic processes, especially the pathways in generating energy and maintaining structural integrity of the cells in RBCs
A

Red Cell Enzymopathies

63
Q
  • The most common enzymopathy
  • An inherited condition which causes non-immune hemolytic anemia
  • Is part of the pentose phosphate pathway
  • Prevents oxidative damage to RBCs
  • This deficiency impairs the ability of the RBCs to form NADPH resulting in hemolysis
A

Glucose-6-phosphate dehydrogenase (G6PD)

64
Q

G6PD

TOF: When G6PD is deficient, NADPH is slightly reduced

A

False (none will be produced at all)

65
Q

G6PD

This is used to convert glutathione in its reduced form which converts hydrogen peroxide into water

A

NADPH

66
Q

G6PD

If this is not reduced to water, it can cause the formation of free radicals within the red cells, producing denatured hemoglobin

A

Hydrogen peroxide (causes oxidative stress)

67
Q

G6PD

  • This refers to precipitated Hgb that adheres to the cell membrane
  • This inclusion is removed by the spleen creating bite cells (leads to acute hemolytic anemia)
A

Heinz bodies

68
Q

G6PD

TOF: There are other metabolic pathways that can generate NADPH in all cells when RBCs lack NADPH-reducing enzymes

A

True

69
Q

G6PD

Glucose-6-phosphate is oxidized to what along with the reduction of NADP to NADPH?

A

6-phosphogluconate

70
Q

Familiarize yourself with the factors that can cause oxidative stress for G6PD positive individuals

A
  1. Infections
  2. Sulfa drugs
  3. Streptomycin
  4. Dilantin
  5. Dapsone
  6. Mothball exposure
  7. Fava beans
71
Q

G6PD Variants

  • The mild form
  • Mildly reduced half-life of G6PD (can still produce NADPH but not as much)
  • Leads to mild intravascular hemolysis with oxidative stress
A

African Variant

72
Q

G6PD Variants

  • The severe form
  • Markedly reduced half-life of G6PD
  • Leads to marked increase in intravascular hemolysis with oxidative stress
A

Mediterranean Variant

73
Q

G6PD deficiency plays a protective role against this parasite for the ff. reasons:
- This parasite cannot stay in RBCs since the RBC will pretty much lyse when exposed to oxidative stress
- It can lead to its own destruction in this case

A

P. falciparum

74
Q

G6PD deficiency is also referred to as this due to allergies involving fava beans

A

Favism

75
Q

G6PD

What is the PBS morphology?

A

Normocytic Normochromic

76
Q

G6PD

Which are increased and which are decreased?

  1. Haptoglobin
  2. Hemopexin
  3. LDH enzyme
  4. Free Hgb
A

Increased: 1 and 2
Decreased: 3 and 4

77
Q
  • An autosomal recessive disorder of pyruvate kinase enzyme deficiency, leading to hemolytic anemia
  • Individuals can be heterozygous or homozygous (worse prognosis)
  • Second most common RBC enzyme defect but the most common cause of RBC enzyme-related non-immune hemolytic anemia
A

Pyruvate Kinase Deficiency

78
Q
  • A genetic defect in the PK enzyme resulting in inefficient glycolysis
  • It is the enzyme responsible for the final step in glycolysis, which is required for maintaining RBC energy (ATP) levels and morphology
  • This leads to a reduction of ATP and shortened RBC lifespan leading to chronic hemolysis
A

Pyruvate Kinase Deficiency

79
Q

What gene is mutated in Pyruvate Kinase Deficiency?

A

PKLR gene

80
Q

Pyruvate Kinase Deficiency

The PKLR gene is located in what chromosome and region of the chromosome?

A

Chromosome 1q21

81
Q

Pyruvate Kinase Deficiency

Familiarize yourself with the events caused by lacking ATP due to PK deficiency

A
  1. Membrane instability
  2. Early RBC desctruction
  3. Cellular dehydration
  4. Altered RBC shape
82
Q

Pyruvate Kinase Deficiency

There is (increased/decreased) 2-3 DPG synthesis within the RBC

A

Increased

83
Q
  • The 3rd most common enzyme abnormality after G6PD and PK causing hereditary non-spherocytic hemolytic anemia
  • Transmitted as an autosomal recessive trait
  • Hemolytic degree is generally mild to moderate
A

Pyrimidine-5’-Nucleotidase Deficiency

84
Q

A lack of Pyrimidine-5’-Nucleotidase can cause the accumulation of precipitated RNA within the reticulocyte causing the formation of what?

A

Basophilic Stipplings

Hematology 1 (32 decks)

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