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Molecular Basis Of Disease > Haemolytic Anaemias > Flashcards

Haemolytic Anaemias Flashcards

1
Q

What is haemolytic anaemia?

A

Anaemia due to shortened Blood cell survival occurring by high rate of destruction of RBC

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2
Q

Describe the variation in blood Hb conc from neonates to adult?

A

VD

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3
Q

Describe the normal Blood cell lifestyle?

A
  • 2 × 10 ^ 11 BC produced per day in the bone marrow
  • They circulate in blood for 120 days without any organelles (300 miles travelled)
  • When senescent (RBC become old), removal occurs by the reticular endothelial system (RES) of the liver + spleen
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4
Q

Describe how the haemolysis cycle occurs?

A
  • Reticulocytosis is an increase in reticuloyctes (developing RBCs)
  • Shortened red cell survival 30-80 days -> Compensation by Bone marrow to increase production -> Increased young cells in circulation = Reticulocytosis +/- nucleated RBC -> incompletely compensated haemolysis: RBC production unable to keep up with decreased RBC life span = Decreased Hb
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5
Q

State 4 clinical findings of haemolytic anaemia?

A
  • Jaundine (yellowing of skin)
  • Pallor (unhealthy pale appearance)
  • Fatigue
  • Splenomegaly (enlargement of the spleen)
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6
Q

State 3 chronic clinical findings of haemolytic anaemia?

A
  • Chronic clinical findings:
  • Gallstones - pigment
  • Leg ulcers
  • Folate deficiency (due to increased use of folate to compensate for lowered RBC count)
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7
Q

State features of a peripheral blood film of someone with HA?

A
  • Polychromatophilia (increased immature RBCs)
  • Nucleated RBCs
  • Thrombocytosis (high platelet count)
  • Neutrophilia with left shift
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8
Q

What morphological abnormalities in a peripheral blood film shows clue that HA is the underlying disorder?

A
  • Spherocytes
  • Sickle cell
  • Target cells
  • Schistosities (fragmented, triangular RBCs)
  • Acanthocytes
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9
Q

State the major bone marrow findings for someone with HA?

A
    1. Reticulocytosis (variable % of reti. In BM)
  • Mild (2-10%) caused via haemoglobinopathies
  • Moderated to marked (10 to 60%) caused via IHAs (immune haemolytic anaemia), HS (hereditary spherocytosis), G6PD deficiency
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10
Q

State the other major bone marrow findings for someone with HA?

A
    1. Erthyroid hyperplasia of BM (increased erythronium precursor cell -› increase in immature RBCs)
  • Normoblastic reaction (production of nucleated RBCs)
  • Reversal of the myeloid:erythroid ratio
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11
Q

Apart from the major findings, state 5 factors which have increased and decreased in the Bone marrow findings with someone with HA? (Low-key go back and figure how these happen)

A

Increased factors:
- Unconjugated bilirubin
- LDH (lactate dehydrogenase)
- Urobilinogen (via metabolism of bilirubin)
- Urinary hemosiderin

Decreased factors:
- Serum haptoglobin protein that binds to free Hb

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12
Q

State the 3 major classifications of haemolytic anaemia stating examples for each sub-classification?

A
    1. Inheritance: Acquired, Paroxysmal nocturnal haemoglobinuria
      b. Hereditary: Hereditary spherocytosis
    1. Site of RBC destruction: Intravascular (within the vascular system): Thrombotic thrombocytopenia purpura/ haemolytic transfusion
      B. Extravascular, II. Autoimmune haemolysis
    1. Intrinsic (intracorpuscular)
      b. Extrinsic (extracorpuscular)
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13
Q

State the subtypes within the intrinsic (intracorpuscular) classification of HA stating examples for each?

A
  • Membrane defects: Hereditary spherocytosis, H elliptocytosis, H pyropoikilocytosis
  • Enzyme defects: G6PD, PK
  • Hb defects: SCD, thalassamias
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14
Q

State the subtypes within the extrinsic (extracorpuscular) classification of HA stating examples within?

A
  • Alloimmune = immune response to nonself antigens
    from members of the same species , which are called alloantigens or isoantigens
  • Two major types of alloantigens are blood group antigens and histocompatibility antigens.
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15
Q

How is the haemolytic disease of the foetus and newborn similar to transfusion reaction?

A
  • Hemolytic disease of the fetus and newborn is similar to a transfusion reaction
  • in the sense that The mother’s antibodies cannot tolerate the fetus’s antigens
  • Which happens when the immune tolerance of pregnancy is impaired.
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16
Q

Describe the sites of RBC destruction when it normally happens? (PART 1)

A
  • The site of BC destruction is most commonly extravascular and specifically, in the spleen (as mentioned above).
  • Macrophages facilitate most extravascular BC breakdown and the components they break RBCs down into are protoporphyrins that is eventually converted to bilirubin via the liver
  • iron that binds to transferrin and globin that is broken down further to individual amino acids.
17
Q

Describe the sites of RBC destruction when it abnormally happens? (PART 2)

A
  • In intravascular haemolysis, rather than RBCs being systematically broken down, the haemoglobin content of RBCs is released into blood and becomes free haemoglobin that is excreted.
  • Iron is also released into the blood from haemoglobin and can also be excreted via urine.
18
Q

Describe normal extravascular haemolysis

A
  • Normal (EV H) -> In Macrophages -> RBCs broken into -> protoporphyrins - converted to bilirubin via the liver
  • (- excreted via gut/kidney, iron that binds to transferrin and globin that is broken down further to individual amino acids.
19
Q

Describe abnormal intravascular haemolysis

A

Abnormal (IV H) -> RBCs lysed -> Hb released into blood + excreted via kidney

20
Q

How do membrane disorders arise from haemolytic anaemia?

A
  • Defects of integral proteins in BC membrane - Autosomal dominant mutations - herditary spherocytosis (- Vertical interaction D - spectrin, band 3, protein 4.2, ankyrin) OR H elliptocytosis (> horizontal interactions D - protein 4.1, glycophorin C + spectrin)
21
Q

State the features of the blood film of hereditary spheroctosis and how it is managed?

A
  • BF - Spherocytosis + elliptocytes
  • Managed -> Monitor, folic acid, transfusion, splenectomy
22
Q

State clinical features of haemolytic spherocytosis?

A
  • Asymptomatic to severe haemolysis
  • neonatal jaundice
  • Jaundice, splenomegaly, pigment gallstones
  • Eosin-5-maleimide (EMA) binding (binds band 3),
  • Positive family history
  • Negative direct AB test
23
Q

Enzyme defects
What pathway is G6PD involved in?

A
  • Glucose-6-phosphate dehydrogenase
  • Used in hexose monophosphate shunt (- Generates NADPH + ‹ glutathione)
  • Protects cell from oxidative stress
24
Q

Enzyme defects
state the effects of G6PD deficiency?

A

Oxidative stress
- oxidation of Hb by oxidant radicals
(- denatured Hb aggregates + forms heinz bodies - binds membrane)
- oxidised membrane proteins (decreased RBC deformability)
- Oxidative haemolysis

25
Q

Enzyme defects
Describe the morphology from the blood film of G6PD deficiency/oxidative haemolysis?

A
  • Bite cells, blister cells, ghost cells + heinz bodies
26
Q

PK
What pathway is pyruvate kinase used in, state its uses + what occurs if deficiency of it occur?

A
  • Glycolytic pathway
  • Generates energy in ATP
  • Maintains BC + deformability
  • Regulates IC cation conc. via cation pumps (Na+/K+ pump) - PK def. - affects these + autosomal recessive
  • Causes chronic non spherocytic HA

Molecular Basis Of Disease (30 decks)

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