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IMED2002 UWA > Haemolytic anaemia and Haemoglobinopathies > Flashcards

Haemolytic anaemia and Haemoglobinopathies Flashcards

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1
Q

What is haemolytic anaemia?

A

Anaemia due to shortened RBC lifespan.

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2
Q

How does the bone marrow respond to drop in RBC lifespan?

A

Usually bone marrow responds and increases erythropoiesis

Red cell production can increase 6 - 8 times

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3
Q

At what RBC lifespan does anaemia occur?

A

<15 days

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4
Q

What causes haemolytic anaemia?

A

RBC survival <15 days

Haematinic deficiency (esp. folate)

Bone marrow disease

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5
Q

What happens if haemolysis occurs in the blood vessels?

A

Hemoglobinemia

Methemalbuminemia

hemosiderinuna

Haemoglobinuria (It mixes with plasma and then gets excreted in urine)

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6
Q

What are signs of RBC destruction?

A

Increased bilirubin (haem breakdown)

Increased LDH (lactate dehydrogenase)

Reduced haptoglobins (Hb-haptoglobin complex)

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7
Q

What blood film evidence indicates red blood cell damage in haemolytic anaemia?

A

Spherocytes (no area of central pallor)

Fragmented red blood cells (schistocytes)

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8
Q

What blood film evidence indicates increased RBC production increase in haemolytic anaemia?

A

Increased reticulocyte production (polychromasia) [not ready yet]

Nucleated RBCs (they should be in bone marrow but are released early)

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9
Q

What are the clinical features of haemolytic anaemia?

A

Anaemia

Jaundice: bilirubin in plasma

Pigment gallstones may occur

Splenomegaly

Ankle ulcers: sickle cell anaemia

Expanded bone marrow

Aplastic crises: parvovirus

Megaloblastic anaemia

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10
Q

What are pigment gallstones caused by?

A

bilirubin is concentrated causing gallstones

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11
Q

What are ankle ulcers caused by?

A

Sickle cell anaemia

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12
Q

What is expanded bone marrow?

A

Erythroid hyperactivity causes increases in BM size (especially in young people)

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13
Q

What is aplastic crises? What is it caused by?

A

Caused by switching off of erythroid activity in the bone marrow. Can be caused by parvovirus infection

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14
Q

Why does haemolytic anaemia show up as megaloblastic anaemia as well?

A

It causes overactivity of folate use and that results in folate deficiency

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15
Q

What causes hereditary haemolytic anaemia?

A

Membrane defect: hereditary spherocytosis

Enzyme defect: G6PD (Glucose 6 phosphate dehydrogenase) deficiency

Globin chain defect: haemoglobiniopathies

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16
Q

What causes acquired haemolytic anaemia?

A

Immune haemolytic anaemia (most common acquired haemolytic anaemia)

Fragmentation haemolysis

Oxidative haemolysis

Liver disease

Infections, renal disease, other

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17
Q

Which membrane proteins are defected in hereditary spherocytosis?

A

Spectrin (peripheral protein)

Ankyrin

Band 3 (integral protein)

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18
Q

How is hereditary spherocytosis inherited?

A

Autosomal dominant

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19
Q

What is the most commonly inherited anaemia?

A

hereditary spherocytosis

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20
Q

Where are RBCs removed in hereditery spherocytosis?

A

In the spleen the RBCs lose their membrane and so red blood cells become spherical and then are destroyed

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21
Q

How does hereditary spherocytosis present in patients?

A

Fluctuating anaemia and jaundice

Sphenomegaly and gall stones

Lab tests show:

Spherocytes on blood film

Polychromasia

Negative DAT

Positive EMA (band-3) [Eosin 5 Maleimide which is a die that binds to band 3]

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22
Q

How is hereditary spherocytosis treated?

A

Splenectomy (spleen is the site of haemolysis)

Folic acid (to avoid folate deficiency)

cholecystectomy

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23
Q

What is a problem with splenectomy that should be considered?

A

People are more prone to bacterial infection when spleen is removed

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24
Q

What is hereditary elliptocytosis?

A

Autosomal dominant condition caused by mutations in spectrin.

It is asymptomatic in most people but 10% have haemolysis

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25
What is G6PD deficiency?
Glucose 6 Phosphate Dehydrogenase deficiency The most common red cell enzyme disorder worldwide (>200 million people affected)
26
What does G6PD do?
Enzyme in the hexose monophosphate shunt which generates reducing power as NADPH
27
What causes G6PD deficiency?
Mutation in gene on X-chromosome.making it more common in males than females
28
Does Australia have high G6PD deficiency?
No, But it must be known because it does exist in some people and people that migrate to australia
29
What is the problem with G6PD?
RBC susceptible to oxidant stress.
30
What triggers haemolysis in G6PD?
Oxidative stress caused by eating raw beans as well as infection, hypoxia, and drugs
31
What kind of red cells form on the blood film?
"Bite" or blister cells
32
What happens after oxidative stress is triggered?
Intravascular haemolysis and oxidised Hb is removed
33
How is G6PD deficiency treated?
Remove / stop / treat offending agent Treat infection Transfuse blood if necessary
34
What happens between crises caused by oxidative stress in G6PD deficiency?
RBC count returns to normal
35
What does pyruvate kinase do?
It is the enzyme that catalyses the last step of glycolysis and is required to make ATP
36
What results if pyruvate kinase is deficient?
Insufficient ATP leads to cell death resulting in haemolytic anaemia
37
How is pyruvate kinase deficiency inherited?
Autosomal recessive inheritance
38
How does pyruvate kinase present itself clinically?
Mild: occasional compensated haemolysis Severe: can present in neonatal period with failure to thrive and splenomegaly
39
What do RBCs look like in pyruvate kinase deficiency?
Prickle-shaped RBCs
40
How is pyruvate kinase deficiency diagnosed?
Pyruvate kinase assay
41
What causes immune haemolytic anaemia?
It is idiopathic in most cases and in some cases it is caused by cancer cells (if leukemia/lymphoma is treated we can bring haemolysis under control)
42
Where does haemolysis take place in immune haemolytic anaemia?
In the spleen
43
What is allo-immune haemolytic anaemia?
Newborn blood damaged by antibodies to Rh in mother.
44
How can drugs cause immune haemolytic anaemia?
Antibody can form against a RBC-drug complex Antibiotics
45
How can immune haemolytic anaemia be tested for?
Using a direct antiglobulin test: Blood sample of someone with immune haemolytic anaemia containing antibodies attached to RBCs is put in a test tube. Coomb's reagent is then added to the mixture and agglutination gives a positive test result
46
What does autoimmune haemolytic anaemia look like on blood film?
Spherocytes are produced (this condition's blood film is identical to spherocytosis) Polychromasia with increased reticulocytes Nucleated RBCs Underlying disease (eg. leukemia)
47
What is fragmentation haemolysis?
A micro-angiopathic haemolytic anaemia where RBCs are damaged structurally
48
What causes fragmentation anaemia?
Heart valve pinhole lesion Fibrin strands in vasculature (can be secondary damage) Damaged blood vessels Physically damaged RBCs due to mechanical movements of the body. Red cell fragmentation
49
What kind of haemolysis does fragmentation haemolysis cause?
Intravascular haemolysis
50
What does fragmentation haemolysis look like on blood film?
Schistocytes
51
What does severe liver disease and renal dysfunction result in?
intravascular haemolysis
52
What cells are seen on blood film of severe liver disease?
Acanthocytes
53
What cells are seen on blood film of people with severe renal dysfunction?
Burr cells (echinocytes) [think of echidna]
54
What are echinocytes?
Echinocyte (from the Greek word echinos, meaning 'hedgehog' or 'sea urchin'), in human biology and medicine, refers to a form of red blood cell that has an abnormal cell membrane characterized by many small, evenly spaced thorny projections. A more common term for these cells is burr cells.
55
What types of infections lead to severe haemolysis?
Severe bacterial sepsis Malaria Clostridium welchii: cause microspherocytes in PB film
56
What other conditions can severe bacterial sepsis cause?
Causes DIC and fragmented red cells
57
What species of plasmodium can cause anaemia?
P. vivax, falciparum, ovale, malariae Trophozoites; schizonts; gametocytes
58
What does Clostridium welchii related anaemia look like on blood film?
Microspherocytes in PB film
59
Where are alpha and beta globin chains located in genome?
2 alpha genes on chromosome 16 2 beta genes on chromosome 11
60
What else does chromosome 11 contain around the beta globin chain?
The delta and gamma genes
61
What are the most common causes of monogenic diseases in the world?
Haemoglobinopathaties
62
What is thalassaemia caused by?
Deficient synthesis of globin chains
63
What are the classifications of thalassemia?
Trait: Carriers Intermedia: shows up at times of stress Major: symptomatic all the time
64
What is beta thalassemia caused by?
reduced beta chain production due to mutations in beta globin gene.
65
What happens when gene for beta thalassemia is homozygous?
When homozygous the condition is present at 3 - 6 months and causes severe anaemia due to loss of fetal gamma chain on which it was dependent.
66
What happens when gene for beta thalassemia is heterozygous?
Asymptomatic
67
Why does thalassemia cause swelling of the spleen and liver?
Because they are overworked trying to remove faults RBCs
68
How are beta thalassemia patients treated?
These people are transfusion dependent.for entire life (3 - 4 bags of packed blood cells a month) but transfusion brings in too much iron so iron is removed by iron chelators.
69
What do the faces of people with thalassemia major look like?
Hair standing on end and cheek bones are prominent
70
How many genes control alpha thalasemia?
4 alpha globin chains
71
How many alpha globin genes are missed in thalassemia minor?
1 or 2
72
How many alpha globin genes are missed in haemoglobin H disease?
3
73
How many alpha globin genes are missed in Hb barts hydrops fetalis?
4
74
What causes sickle cell anaemia?
A mutation encoding haemoglobin beta forming crystal and HbSS. Sickle shaped red cells can occlude blood vessels

IMED2002 UWA (29 decks)

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