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GEN PATH > RBC DISORDERS 2 > Flashcards

RBC DISORDERS 2 Flashcards

1
Q

Quantitative vs Qualitative

  1. Anemia
    - blood loss
    - decreased production
    - increased destruction
  2. Polycythemia
A

Quantitative

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2
Q

Quan vs Quali

  1. abnormal in morphology
    - abnormal in function
    - intracorpuscular/Inherent to red cells
A

Quali

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3
Q

Reduction, from baseline value of:
– total Red Blood Cells (RBCs)
– circulating Hemoglobin (Hb)
– amount of Hematocrit (Hct)

A

Anemia

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4
Q 
Parameters of Anemia
Adult Male
RBC: 
Hematocrit: 
Hemoglobin:

Adult Female
RBC:
Hematocrit:
Hemoglobin:

A

Adult Male
RBC: 4.6 – 6.0 x 1012/L
Hematocrit: 40 – 50 % (0.40 – 0.50 L/L)
Hemoglobin: 14.0 – 18.0 g/dL (140 – 180 g/L)

Adult Female
RBC: 4.0 – 5.4 x 1012/L
Hematocrit: 35 – 49 % (0.35 – 0.49 L/L)
Hemoglobin: 12.0 – 15.0 g/dL (120 – 150 g/L)

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5
Q

Result of the compensatory mechanism to Anemia

A

Erythropoiesis (increased reticulocytes in the peripheral blood

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6
Q

• also known as Minkowski–Chauffard syndrome
• Intrinsic defect in the red blood cell membrane skeleton
• Inherited disorder:
– 75% - an autosomal dominant inheritance pattern
– Compound heterozygosity (inheritance of 2 different defect)
• Highest prevalence in Northern Europe – 1 in 5,000
- autosomanl dominant disorder
- characterized by 1. spherocytes, 2. splenomegaly, 3. familial occurence

A

HEREDITARY SPHEROCYTOSIS

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7
Q

Clinical manifestations:Hereditary Spherocytosis

A
  • chronic anemia,
  • splenomegaly,
  • gallstones (bilirubin stones) ,
  • aplastic crisis.
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8
Q

Defect in Hereditary Spherocytosis

A

Deficiency of Beta Spectrin or Ankyrin -> Loss of membrane -> becomes more spherical -> Destruction in Spleen

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9
Q

Laboratory of Hereditary Spherocytosis

A
  1. Those of chronic extravascular hemolysis
  2. Increased pigment catabolism
  3. Erythroid hyperplasia
  4. Reticulocytosis
  5. Direct antiglobulin test (DAT) – negative
  6. MCV normal; MCHC often increased
  7. OFT increased
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10
Q
  • Red cells arte suspended in a series of tubes containing hypotonic solutions of NaCl varying from 0.9 to 0.0%, incubated at room temperature for 30 minutes, and centrifuged.
  • cells with decreased surface/volume ration, have limited capacity to expand in hypotonic solutions, hence undergo lysis.
A

Osmotic Fragility Tests

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11
Q
  • Sterile, defibrinated blood is incubated at 370C for 48 hours.
  • Cells undergo series of changes —- become more spherocytic
A

Autohemolysis Tests

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12
Q

HEREDITARY SPHEROCYTOSIS
Clinical Features:

  • Triggered by Acute parvovirus infection. Around 1-2 weeks
  • Produced by intercurrent events (ie infectious mononucleosis) -> increased spleenic destruction.
A
  • Aplastic Crises

- Hemolytic Crises

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13
Q

Tx for HEREDITARY SPHEROCYTOSIS

A
  • Supportive

- Splenectomy

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14
Q
  • is involved in the Hexose Monophosphate shunt/Pentose Phospate Pathway -> Reduction of oxidized form of glutathione/detoxifies accumulated peroxide.
  • Recessive x-linked trait: Males > Females
  • Variants that cause most of the clinically significant Hemolytic anemia:
    1. G6PD-
  • 10% of Americal Blacks
    2. G6PD Mediterranean – prevalent in the Middle East
    • Protective against Plasmodium falciparum
A

Glucose-6-Phosphate Dehydrogenase

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15
Q

Triggers of hemolysis in GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY

A
  1. Infections
    - Viral hepatitis, Pneumonias, Typhoid fever
  2. Drugs
    - Anti-malarial drugs, Sulfonamides, Nitrofurantoin
  3. Food – Fava beans
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16
Q

GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY
Clinical Features:
Acute Hemolysis
Recovery phase:

A

Usually starts 2 to 3 days following exposure

  • Characteristics
    1. Anemia
    2. Hemoglubinuria
    3. Hemoglobinemia
  • No features related to chronic hemolysis (splenomegaly and cholelithiasis.

Recovery phase:
- Reticulocytosis

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17
Q

Detects deficiencies in the pentose phosphate pathway:

  • Glucose-6-Phosphate
  • Dehydrogenase deficiency
  • Glutathione reductase
  • Glutathione peroxidase
A

Ascorbate Cyanide Screening Test

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18
Q

Morphology of GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY

  • macrophages eat the red blood cells
  • due to high level of oxidants -> cross-linking of reactive sulfhydryl groups of hemoglobin -> denatured hemoglobin
A
  • bite cells

- Heinz bodies

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19
Q

• An inherited disease of the red blood cells that is common among blacks
• Affect the proteins inside the red blood cells - HEMOGLOBIN.
• Deoxygenated red blood undergo transformation from normal biconcave disk to sickle - shaped structure.
- sickling phenomenon is due to polymerization of sickle hemoglobin Hb S
-

A

SICKLE CELL DISEASE

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20
Q
  • HB SS (α2βς2) - due to point mutation

- Valine is substituted for glutamic acid at the 6th position of β - globin chain.

A

Homozygous form

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21
Q

• Red blood cells sickle when O2 saturation is < 40%
Example: Unpressurized aircraft, Deep sea diving
• Does not affect life span of patient.
• Normal blood counts and morphology
• Does not require treatment

A

Heterozygous form - Hb AS

22
Q

Major Pathologic Manifestations: Sicle Cell Disease

A
  1. Chronic hemolysis
  2. Microvascular occlusion
  3. Tissue damage
23
Q

SICKLE CELL DISEASE Morphology:

  1. Peripheral blood picture
    - Anemia -
    - Increased polychromasia -
    - Normoblast
    - Target cells
    - Howell - Jolly and Pappenheimer bodies
    - Sickle cells
A
  1. Peripheral blood picture
    - Anemia - usually normocytic normochromic
    - Increased polychromasia - reticulocytosis
    - Normoblast may be seen
    - Numerous Target cells
    - Howell - Jolly and Pappenheimer bodies
    - Numerous Sickle cells
24
Q

SICKLE CELL DISEASE Morphology:

Bone marrow

A

Bone marrow

  • Normoblastic hyperplasia
  • Increased Iron storage
25
Q

Diagnose:

  • Cellulose acetate electrophoresis at pH 8.6
  • 35 - 45 % Hb S Normal Hb F
  • 50 - 65 % Hb A Normal to slightly inc. Hb A2
A

Hemoglobin Electrophoresis

26
Q

• Adding Sodium Metabisulfite to blood enhances deoxygenation and sickling of the red blood cell.
• Drawback:
1. Does not distinguish Hb AS from Hb SS and other Hb S syndromes.
2. Positive test may occur with other rare abnormal hemoglobin (Hb C Harlem and Hb I).
3. False negative test may occur if Hb S is less than 10% or there is inadequate deoxygenation.

A

Sickling Test – Metabisulfite

27
Q
  • Adding Sodium hydrosulfite results to lysis of RBC and reduction of Hb S.
  • Polymers of Hb S obstruct light rays and produce opacity.
  • Useful for screening
A

Solubility Test – Dithionate

28
Q
  • Increasing proportion of red blood cells lyse upon exposure to increasing hypo-osmotic saline solution.
  • OFT usually decreased
  • Not specific
A

Osmotic Fragility Test

29
Q

SICKLE CELL DISEASE

Treatment:

A
  1. Symtomatic
    - Pain Management - Narcotics
    ex. Morphine and Hydromorphone
    - Reduce number of “crises”
    HYDROXYUREA (Charade) Exchange Transfusion
  2. Bone marrow transplant
30
Q
  • the medical term for a deficiency in the number of red blood cells (anemia)
  • Heterogenous group of heritable anemias that have in common quantitatively defective synthesis of either α or β chains of the normal hemoglobin A tetramer (α2β2)
  • Originally observed in Italian and Greek coast.
  • Also seen in the Mediterrenean basin, Middle East, Parts of Pakistan, India, Southeast Asia, Southern Part of USSR, China and Northern Regions of African continent.
  • Most frequent in malaria epidemic areas.
A

THALASSEMIA

31
Q

Alpha VS Beta Thalassemia

  • deletions of alpha-globin gene
  • symptoms can begin in fetal life
  • complicated inheritance- 4 alpha genes
A

Alpha

32
Q

Alpha VS Beta Thallasemia

  • nonsense, splice and frameshift mutations in beta globin gene
  • symptoms begin in infncy/childhood
  • simple AR inheritance; genotype-phenotype correlation
A

Beta

33
Q

β-THALASSEMIA
Molecular Pathogenesis:

Extremely heterozygous

  1. Most commonly by ____ on chromosome 11
  2. Less commonly ____ of part of the gene
A
  • point mutation

- deletion

34
Q

β-THALASSEMIA
Molecular Pathogenesis:

Categories

  1. βo mutations associated with ___ β-globin synthesis
  2. β+ mutations ___ but detectable βo sythesis
A
  • absent

- reduced

35
Q

Mechanism of Anemia (β-THALASSEMIA):

A
  1. Deficiet Hb A synthesis
    - “Underhemoglobinization” microcytic hypochromic red cells with abnormal oxygen
    transport capacity
    - Diminished survival of red cells and their precursors
  2. Ineffective erythropoiesis
  3. Extravascular Hemolysis
36
Q

Manifestation of 1.Heterozygous β- Thalassemia/β- Thalassemia Minor/
Cooley’s Trait (β0/β or β+/β)

A
  • Moderate reduction of Hb A (α2 β2)

- Increased Hb A2 (α2δ2)

37
Q

Manifestation of Homozygous β -Thalassemia / β -Thalassemia Major/ Cooley’s Anemia (β0 /β0 or β+/ β+)

A

Normal or moderately increased Hb A2 (α2δ2)

* Increased Hb F (α2γ2)

38
Q

β – Thalassemia Morhology: Peripheral Blood

  • mild anemia with some hypochromia and microcytosis
  • poikilocytosis
  • basophilic stippling
  • target cells
A

Heterozygous

39
Q

β – Thalassemia Morhology: Peripheral Blood

  • hypochromic and microcytic anemia
  • marked anisocytosis and poikilocytosis
  • target cells, ovalocytes, siderocytes, nucleated RBCs
  • extreme normoblastosis
  • cabot rings, howell-jolly bodies
A

Homozygous

40
Q

β – Thalassemia Morhology: Bone Marrow

  • Normoblastic hyperplasia and increased Iron storage
  • Marked normoblastic hyperplasia, Increased Iron storage, Increased sideroblast, Normoblast with inclusions
A
  • Heterozygous

- Homozygous

41
Q

β – Thalassemia Morhology:

Heterozygous vs Homozygous:

Osmotic Fragility Test
Blood Indices
Increased Indirect Bilirubin

A

Heterozygous - Decreased OFT

                       - Increased RBC
                       - Decreased HCT and Hb
                       - Low MCH and MCV; N to Low MCHC

Homozygous - Increased OFT
- Severe derangement

Increased Indirect Bilirubin: ALL

42
Q

β – Thalassemia Treatment:

Symtomatic

A
  1. Iron chelation

2. Transfusion therapy

43
Q 
- Reflects the failure of one or more of the four (4) α - gene loci on chromosome 16 to 
function.
Histopathogenesis:
- 80 % of cases reflect gene deletion
- less commonly by point mutation
  • Limited to the tropical and subtropical regions of the world.
  • Carriers have been reported to resist infection by Plasmodium falciparum.
A

Alpha – Thalassemia

44
Q

Alpha – Thalassemia Syndrome:

  • Deletion of one (1) α gene or inactivation by point mutation.
  • Hematologic parameters are normal.
  • Infants have 1 to 2 % of total Hb is Hb Bart’s.
A

Silent Carrier State /α+ - Thalassemia or α- - Thalassemia 2 /(αα/α-)

45
Q

Alpha – Thalassemia Syndrome:

  • Deletion of two (2) gene 3 Molecular mechanisms:
    a. Deletions - 17 different types
    b. Truncation of chromosome 16
    c. Removal of the key regulatory region HS 40
  • Mild hemolytic anemia
  • Infants have Hb Bart’s of no more than 5 %
A

α - Thalassemia Trait / α –Thalassemia Minor /α 0- Thalassemia or α+ -Thalassemia 1/(αα/– or α-/α-)

46
Q

Alpha – Thalassemia Syndrome:

  • 3 genes deleted
  • Moderate hemolytic anemia with hypochromia and microcytosis.
  • First year of life with up to 25 % Bart’s Hb
  • Adult Hb A predom
A

Hemoglobin H Disease (α-/– or αα/– cs)

47
Q

Alpha – Thalassemia Syndrome:

  • Complete deletion of 4 genes
  • Death in - utero or Hydrops fetalis
A

Bart’s Hemoglobin

48
Q

Diagnosis - Alpha - Thalassemia

All forms of Thalassemia show:

A
  1. Hypochromic microcytic anemia
  2. Ineffective erytropoiesis
  3. Hemolysis
49
Q

Diagnosis - Alpha - Thalassemia:

Hydrops with Bart’s Hb

A
  • Marked anisocytosis and poikilocytosis
  • Marked microcytosis and erythroblastosis
  • Absent ABO and Rh incompatibility
  • Alkaline Electrophoresis:
    Large quantities of Hb Bart’s (γ4)
    Some Hb H (β4)
50
Q

Diagnosis - Alpha - Thalassemia:
Hemoglobin H Disease
- Blood
- Electrophoresis

A 
- Blood: Decreased MCV and MCH 
  > Hypochromia, target cells and anisopoikilocytosis
  > Reticulocytes usually 4 to 5 %
  > Hb H precipitates (BCB)
  > Heinz bodies
- Electrophoresis:
    > Hb H (β4) accounts for 4 to 30 %
    > Traces of Hb Bart’s (γ4)

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