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MEH > Haemolytic Anaemia and Haemoglobinopathies > Flashcards

Haemolytic Anaemia and Haemoglobinopathies Flashcards

1
Q

What are Haemoglobinopathies

Compare 2 types

A

Inherited disorders in globin genes

  • Sickle cell disease: Abnormal globin chain variants with altered stability and/or function.
  • Thalassaemia: Reduced/ absent expression of normal globin chains
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2
Q

Compare the proportions of HbF and HbA before and after birth

A

Before birth, HbF is the main form but HbA is also synthesised. After birth, HbA steadily increases to become the dominant form

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3
Q

How many alpha-globin genes do humans have
How many from mother and father

In alpha thalassemia, how many globin chains can be deleted

A

4 genes, 2 from mum 2 from dad

1-4

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4
Q

If only one Alpha-globin gene is deleted, what disease occurs

How severe is the anaemia

A

Silent carrier state

Asymptomatic

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5
Q

If only 2 Alpha-globin genes are deleted, what disease occurs

How severe Is the anaemia
Which genes are deleted
What other kind of thalassaemia does it resemble

A

Alpha-thalassaemia trait
Minimal/ no anaemia
Both genes of one chromosome/ one gene on each chromosome

Beta-thalassaemia minor/ trait

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6
Q

If only 3 Alpha-globin genes are deleted, what disease occurs, How severe is it

What forms and how do RBCs appear

Which other form of thalassaemia is resembled

A

HbH disease, moderately severe

Beta-globin tetramers (HbH) form-> Hypochromic microcytes + target cells + Heinz bodies

Beta-thalassaemia intermedia

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7
Q

If 4 Alpha-globin genes are deleted, what disease occurs, How severe is it

What forms and why is this bad

A

Hydrops fetalis, severe usually results in death in utero

Hb Bart (Tetramers formed from excess Y-globin) in foetus forms, can’t deliver O2 to tissues

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8
Q

What causes Beta thalassaemia

What do Beta0 and Beta+ genes denote

A

Beta-globin gene mutation (Rather than deletion)

Beta0 denotes absence of chain production
Beta+ denotes reduced chain production

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9
Q

How severe is Beta-thalassaemia minor/ trait
What does it resemble

Describe its genotype

A

Usually asymptotic with mild anaemia, resembles Alpha-thalassaemia trait

Heterozygous with one normal, one abnormal gene (B0/B) or (B+/B)

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10
Q

How severe is Beta-thalassaemia intermedia

What does it resemble

A 
Severe anaemia (Not enough to need regular transfusions)
Resembles HbH disease
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11
Q

How severe is Beta-thalassaemia major
When does it manifest and why?

Describe its genotype

A

Severe, requires transfusions
6-9 months after birth, as HbA becomes dominant

Homozygous (B0/B0 OR B+/B+)

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12
Q

Explain 5 consequences of thalassaemia

A
  • Extramedullary haemopoiesis-> Splenomegaly and heptaomegaly
  • Expansion of haematopoiesis into bone cortex-> impaired growth and skeletal deformities
  • Reduced oxygen delivery-> EPO stimulation
  • Iron overload (due to excessive absorption due to infective haematpoiesis and repeated blood transfusions)
  • Reduced life expectancy
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13
Q

Name 4 treatments for thalassaemia and one preventive measure

A
  • Red cell transfusion from childhood
  • iron chelation (delays iron overload)
  • folic acid
  • holistic care to manage complications
  • Pre conception counselling and antenatal screening
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14
Q

What is sickle cell disease
What is the abnormality
What is the mutant Haemoglobin called

A

Inherited disease in which Beta-globin gene is mutated
Glutamic acid substituted by valine
HbS

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15
Q

Compare the outcomes of

  1. Heterozygous HbS
  2. Homozygous HbS
A
  1. Mild asymptomatic anaemia

2. Sever sickling syndrome

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16
Q

Why is sickle cell anaemia usually well tolerated

When do problems occur and how
What happens when this occurs repeatedly

A

HbS gives up O2 to tissues more readily than HbA

In low oxygen state, as deoxygenated HbS forms polymers which cause cell to form a sickle shape

Cells become irreversibly sickled and cause occlusion in vessels

17
Q

Identify 5 possible conditions caused by Sickle Cell Anaemia

A
  • Splenic atrophy
  • Avascular necrosis
  • Acute chest syndrome
  • Stroke
  • Priapism (painful erection)
18
Q

What is the normal lifespan of an RBC

In which 2 regions can haemolysis occur

A

120 days
Intravascular (Vessels)
Extravascular ( Spleen + RES)

19
Q

What are 3 types of Sickle Cell Crisis

A
  1. Haemolytic
  2. Aplastic ( Bone marrow stops working)
  3. Vaso-occlusive (Most common, painful bone crisis)
20
Q

What are 2 types of haemolytic anaemia and in which type are cells more fragile

What are 3 lab findings of Haemolytic anaemia

A

Inherited- More fragile
Acquired

Raised reticulocytes
Raised bilirubin
Raised LDH (Lactase Dehydrogenase)

21
Q

What are 4 causes of inherited haemolytic anaemia

What are 5 causes of acquired haemolytic anaemia

A

Inherited:

  • Glycolysis defect
  • G6PDH deficiency
  • Membrane protein defect
  • Hb defect

Acquired:

  • Mechanical damage
  • Heat damage
  • Enzymatic damage
  • Oxidant damage
  • Antibody damage
22
Q

When is haemolytic anaemia more severe than chronic disease

What are 3 outcomes

A

If Hb is very low/ Hb falls suddenly

  • Bilirubin accumulation-> jaundice
  • Bilurubin accumulation->Pigment gallstones
  • Splenomegaly
23
Q

What are 2 outcomes of massive sudden haemolysis

What are 2 signs of jaundice

A
  • Cardiac arrest (lack of oxygen)
  • Hyperkalemia (Released intracellular contents)
  • Yellow discolouration of skin and sclera
  • Dark urine (conjugated bilirubin)
24
Q

What are 3 inherited defects in cell membrane structure

A

Hereditary Spherocytosis
Hereditary Elliptocytosis
Hereditary Pyropoikilocytosis

25
Q

In Hereditary Elliptocytosis, which protein is most commonly defected

Which other 3 can be defected

A

Spectrin

Glycophorin C
Band 3
Band 4.1

26
Q

In Hereditary Pyropoikilocytosis, which protein is defected

What add cells abnormally sensitive to

A

Spectrin

Heat

27
Q

Explain the 2 classes of Autoimmune Haemolytic Anaemia

A

Warm (IgG) or Cold (IgM) depending on the temp. antibodies react best at

MEH (20 decks)

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