Haemotology Flashcards

1
Q

What are the different microcytic anaemias?

A
  1. Iron deficiency
  2. Haemoglobinopathies e.g. Thalassaemia, sickle cell
  3. Anaemia of chronic disease e.g. CKD and so lack of EPO
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2
Q

WHAT IS THALASSAEMIA?

https://www.youtube.com/watch?v=uK_uIBHnOWo&t=4s

A

The thalassaemias are genetic diseases of unbalanced Hb synthesis, with under-production (or no production) of one globin chain

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3
Q

What is the pathology of thalassaemia?

What happens to the red blood cells?

A
  1. Unmatched globins precipitate
  2. Damaging RBC membranes
  3. Causing their haemolysis while still in the marrow.
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4
Q

What are the different types of Thalassaemia?

What different treatments do they require?

A

Thalassaemia Major
Transfusion dependent

Thalassaemia Intermedia
Less severe anaemia and can survive without regular blood transfusions

Thalassaemia Carrier/heterozygote
Asymptomatic.

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5
Q

What type of anaemia is thalassaemia?

A

Microcytic

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6
Q

WHAT IS BETA THALASSAEMIA?

What do you get less of?

What happens as a result?

A

In homozygous beta-thalassaemia, little/no normal beta chain production

EXCESS alpha chains.

Alpha chains combine w. whatever beta, delta or gamma chains available increased production of HbA2& HbF.

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7
Q

What is the cause of beta thalassemia?

Which chromosome is it defected in?

A

Point mutations in beta-globin genes

Chromosome 11

Decreased beta-chain production (beta+) or absence (beta0)

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8
Q

What is beta thalassemia major called?

A

Beta thalassaemia major (Cooley’s anaemia) denotes abnormalities in both beta-globin genes.

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9
Q

When does beta thalassaemia major present?

A

6 -12 months

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10
Q

What are the symptoms of beta thalassaemia major?

A

Failure to feed, listless, crying, pale.

Bones widen due to increased activity
Skull bossing

Anaemia

Hepatosplenomegaly
Lots of RBCs need to be destroyed

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12
Q

What is beta thalassaemia minor or trait?

A

This is a carrier state

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13
Q

What are the symptoms of beta thalassaemia minor?

A

Usually asymptomatic

Mild, well-tolerated anaemia (Hb >90g/L)

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14
Q

What are the symptoms of beta thalassaemia intermedia?

A
  1. Moderate anaemia but not requiring transfusions
  2. There may be splenomegaly
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15
Q

What are the tests for Beta thalassaemia?

A
  1. FBC & film
    • Hypochromic & microcytic anaemia
    • Target cells are seen
    • Reduced reticulocytes and nucleated RBCs
  2. Dx by Hb electrophoresis
    • Shows increased HbF & absent/low HbA.
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16
Q

What is the treatment for beta thalassaemia major?

A

BLOOD TRANSFUSIONS

Give iron chelation
Desferrioxamine
Decrease iron loading

Ascorbic acid
Increased urinary excretion of iron.

Long term folic acid supplements.

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17
Q

What happens when a child with Thalassaemia major has treatment by continuous blood transfusions?

A

Children require lifelong blood transfusions.

Consequence is an progressive increase in body iron load.

Can’t eliminate the excessive iron

Patients inexorably develop a clinically worsening hemosiderosis

Liver and spleen, leading to liver fibrosis and cirrhosis.

Endocrine glands and the heart, resulting in diabetes, heart failure and premature death.

Death ultimately occurs, mainly due to cardiac hemosiderosis.

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18
Q

What does degree of symptoms depends of in alpha Thalassaemia?

A

4 deletions
HbBarts, infants are STILLBORN(hydrops fetalis).

3 deletions
SEVERE anaemia.

2 deletions
Often ASYMP. carrier, may have mild anaemia.

1 deletion
Close to normal.

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19
Q

WHAT IS SICKLE CELL ANAEMIA (GENETICS)?

What type of anaemia is it?

https://www.youtube.com/watch?v=1ql-X60CUNQ&t=6s

A
  1. Sickle-cell anaemia is an autosomal recessive disorder causing production of abnormal beta globin chains.
  2. Microcytic anaemia
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20
Q

What is haemoglobin S?

A

Variant haemoglobin arising because of a point mutation in the b globin gene.

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21
Q

What happens with a carrier of sickle cell disease?

A

Carriers of HbS are symptom free

Carriage offers protection against falciparum malaria

Sickle cell diseases arise in the homozygous state (SS) or in combined heterozygotes (SC or Sb thalassaemia).

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22
Q

What gene changes occur in sickle cell anaemia?

A
  1. Thiamine for adenine in 6th codon
  2. Beta globin gene
  3. Glutamic acid leaves
  4. Valine comes in
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23
Q

What is the pathology of sickle cell disease?

What happens to the red blood cell?

A
  1. HbS polymerizes when deoxygenated
  2. RBCs deform, producing sickle cells
  3. Which are fragile and haemolyse, and also block small vessels
  4. Sickling cells appear at acidosis at a time when they deposit lots of oxygen
24
Q

What are the symptoms of sickle cell disease?

Think about the crises’!

A
  1. Fatigue and Anaemia
  2. Pain Crises
  3. Dactylitis and Arthritis
  4. Bacterial Infections
  5. Leg Ulcers
  6. Aseptic Necrosis and Bone Infarcts
26
Q

What are the different crises for sickle cell disease?

A
  1. Haemolytic
  2. Aplastic crisis (sudden reduction in marrow production)
  3. Sequestration crisis (There is pooling of blood in the spleen ± liver)
  4. Vaso-occlusive ‘painful’ crisis
27
Q

What are the tests for sickle cell disease?

A
  1. Hb ELECTROPHARESIS
    • For dx
    • HbSS present and absent HbA
  2. Blood film
    • SICKLED erythrocytes
  3. FBC
    • Low Hb, high reticulocyte count
  4. Screen neonate
    • Blood/heel prick tes
28
Q

What are the treatments for sickle cell anaemia?

A
  1. Prophylactic ABX
    • Daily penicillin.
    • Pneumococcal & influenza vaccine
    • Folic acid
  2. Pain relief for crisis
    • NSAIDs/paracetamol
  3. Hydroxyurea
    • Hydroxycarbamide
    • Increase conc. of HbF
  4. Transfusions
    • Bone marrow transplant
29
Q

What are some common complications of sickle cell disease?

A

Acute complications
Painful crisis
Sickle chest syndrome
Stroke

Chronic complications
Renal impairment
Pulmonary hypertension
Joint damage

30
Q

WHAT HAEMOLYTIC DISEASE OF THE NEWBORN?

A

Haemolytic disease of the newborn is said to occur when haemolysis of a neonate’s red blood cells that is most often caused by antibody from the mother - rhesus incompatibility or ABO incompatibility.

31
Q

What are the causes of haemolytic disease of the newborn?

A

Rhesus haemolytic disease

ABO haemolytic disease

Hereditary spherocytosis

Glucose-6-phosphodehydrogenase

32
Q

What are the investigations for haemolytic disease of the newborn?

A
  1. Full blood count, with attention to haemoglobin, white cells and reticulocytes
  2. Platelets
  3. Infant blood group and Coombs test
  4. Maternal blood group and haemolysins
  5. Red cell enzyme assay may be a helpful second line investigation
  6. Blood film and osmolar fragility may diagnose spherocytosis
33
Q

What is the treatment for haemolytic disease of the newborn?

A
  1. Before Birth
    • Anti-D Rh gammaglobulin is administered to each Rhesus negative non-sensitized woman who delivers a rhesus positive child, has an abortion, an amniocentesis, chorionic villus sampling, or external cephalic version
  2. After birth
    • Depending on the severity of the disease, the neonate might undergo phototherapy, exchange transfusion, or drugs to counter cardiac failure such as diuretics.
34
Q

WHAT IS FANCONI’S ANAEMIA?

A

Fanconi’s anaemia is a rare autosomal recessive disease characterised by:

  1. Bone marrow failure
  2. Developmental abnormalities
  3. Cancer susceptibility
35
Q

What are the clinical features of fanconi’s anaemia?

A
  1. Haematological:
    Aplastic anaemia
    Increased risk of acute myeloid leukaemia
  2. Neurological
  3. Skeletal abnormalities:
    Short stature
    Thumb/radius abnormalities
  4. Cafe au lait spots
36
Q

What are the investigations for fanconi’s syndrome?

A

On examination of the blood there is a pancytopaenia.

Analysis of the chromosomes will reveal a high level of breaks and gaps.

The diagnostic test is the DEB challenge test:
DEB (diepoxybutane) is an alkylating agent
Cells cultured from a patient with Fanconi’s anaemia are more sensitive to DEB than control cells
The test is sensitive and specific but does not distinguish between the five complementation groups

37
Q

What is the treatment for fanconi’s anaemia?

A
  1. Children usually die within 2 years of the diagnosis
  2. In up to 10% the child develops an acute leukaemia; in a further 10% there are other malignancies
  3. Androgens and steroids delay progression of the condition
  4. Bone marrow transplantation - there is a 70% survival at 5 years post-marrow transplant
38
Q

WHAT IS IMMUNE THROMBOCYTOPENIA?

A

IgG antibodies form to platelet and megakaryocyte surface glycoproteins

Opsonized platelets are removed by reticuloendothelial system

39
Q

What is primary ITP?

A

May follow viral infection / immunisation esp in children

Varicella

40
Q

What is secondary ITP?

A

Occurs in association with some malignancies

  1. Chronic Lymphocytic Leukaemia (CLL)
  2. Infections e.g. HIV / HepC
41
Q

What is chronic ITP?

A

Chronic ITP runs a fluctuating course of bleeding, purpura, epistaxis and menorrhagia.

There is no splenomegaly.

42
Q

What are the symptoms for ITP?

A

Easy bruising

Purpura

Epistaxis (nose bleed)

Menorrhagia (heavy bleed at period)

44
Q

What are the tests for ITP?

A

Thrombocytopenia

Increased megakaryocytes in marrow

Antiplatelet autoantibodies often present

45
Q

How do you treat immune thrombocytopenia?

A
  1. Need to do bone marrow biopsy to rule out leukaemia
  2. Corticosteroids i.e. prednisolone
  3. Splenectomy
46
Q

What is haemophilia?

What is each haemophilia a deficiency in?

A
  1. These are a group of genetic disorders characterized by a deficiency of one of the coagulation pathway factors.
  2. Haemophilia A is due to a deficiency of factor VIII
  3. Haemophilia B (Christmas disease) there is a lack of factor IX
47
Q

What are the clinical features of haemophilia?

A
  1. Haemoarthroses, haematomas
  2. Prolonged bleeding after surgery or trauma
48
Q

What are the investigations for haemophilia?

A
  1. Prolonged APTT
  2. Bleeding time, thrombin time, prothrombin time normal
49
Q

What is the management for haemophilia?

A
  1. Give factor they are deficient in
  2. Analgesia for haemoarthroses
  3. Splints
50
Q

WHAT IS VON WILLEBRAND’S DISEASE?

A

Von Willebrand’s disease is caused by congenital deficiency of vWF, a protein cofactor essential for normal platelet adhesion and for the transport of Factor VIII.

51
Q

What is the inheritance for von Willibrand disease?

A

Autosomal dominant

52
Q

What are the clinical features of von Willebrand’s disease?

A
  1. Mild haemophilia with bleeding following mild trauma or surgery
  2. Haemarthroses
  3. Soft tissue haematomas
  4. Epistaxis
  5. Menorrhagia
53
Q

What are the investigations for von Willebrand disease?

A
  1. Prolonged bleeding time
  2. APTT may be prolonged
  3. Factor VIII levels may be moderately reduced
  4. Defective platelet aggregation with ristocetin
54
Q

What is the treatment for von Willebrand disease?

A
  1. Tranexamic acid for mild bleeding
  2. Desmopressin (DDAVP): raises levels of vWF by inducing release of vWF from Weibel-Palade bodies in endothelial cells
  3. Factor VIII concentrate
55
Q

WHAT IS ACUTE LYMPHOBLASTIC LEUKAEMIA?

A
  1. Acute lymphoblastic leukaemia (ALL) is the most common malignancy affecting children and accounts for 80% of childhood leukaemias.
  2. The peak incidence is at around 2-5 years of age and boys are affected slightly more commonly than girls
56
Q

What are the features of ALL?

A
  1. anaemia: lethargy and pallor
  2. neutropaenia: frequent or severe infections
  3. thrombocytopenia: easy bruising, petechiae