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Phase 3a Paediatrics > Haematology > Flashcards

Haematology Flashcards

1
Q

What is Thalassaemia?

A

Thalassaemia = genetic defect in the protein chains that make up haemoglobin

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2
Q

What inheritance pattern does alpha + beta thalassaemia follow?

A

Autosomal recessive

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3
Q

Defects in the alpha chains in haemoglobin production lead to….

A

Alpha thalassaemia

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4
Q

Defects in the beta chains in haemoglobin production lead to….

A

Beta thalassaemia

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5
Q

What are the red cells like in patients with thalassaemia?

A

The RBCs are more fragile + break down more easily

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6
Q

What happens to the spleen in thalassaemia?

A

Splenomegaly
(Spleen = acts like a sieve to filter blood + remove older RBCs → spleen collects all the destroyed RBCs → splenomegaly)

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7
Q

What bone changes occur in thalassaemia and why do they occur?

A

Pronounced forehead + malar eminences (cheekbones)
* Bone marrow = expands to produce more RBCs → to compensate for chronic anaemia
* Casuses susceptibility to fractures + prominent features → pronounced forehead + malar eminences

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8
Q

An infant presents with:
* Fatigue
* Pallor
* Jaundice
* Gallstones
* Splenomegaly
* Poor growth and development
* Pronounced forehead and malar eminences
On his blood tests: microcytic anaemia (low MCV).
Possible diagnosis?

A

Thalassaemia

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9
Q

What investigations do you request when you suspect thalassaemia?

A
  • FBC → shows microcytic anaemia
  • Haemoglobin electrophoresis → diagnoses globin abnormalities
  • DNA testing → looks for genetic abnormality

Pregnant women = offered a screening test for thalassaemia

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10
Q

What test is used to diagnose globin abnormailities?

Used in thalassaemia

A

Haemoglobin electrophoresis

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11
Q

What is a major complication with thalassaemia?

A

Iron overload
(causes similar effects to haemochromatosis)

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12
Q

Why does iron overload occur in thalassaemia?

A

As a result of:
* Faulty creation of RBCs
* Recurrent transfusions
* Increased absorption of iron in gut (response to anaemia)

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13
Q

What blood test is required and monitored for iron overload in thalassaemia patients?

A

Serum ferritin

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14
Q

How do you manage iron overload in thalassaemia patients?

A
  • Limiting transfusions
  • Iron chelation
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15
Q

What are the effects of iron overload in thalassaemia?

A
  • Fatigue
  • Liver cirrhosis
  • Infertility
  • Impotence
  • Heart failure
  • Arthritis
  • Diabetes
  • Osteoporosis and joint pain
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16
Q

What is alpha thalassaemia caused by?

A

Defects in the alpha globin chains coded on chromosome 16

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17
Q

What is the management for alpha-thalassaemia?

A
  • Monitoring the full blood count
  • Monitoring for complications
  • Blood transfusions
  • Splenectomy may be performed
  • Bone marrow transplant can be curative
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18
Q

What is beta-thalassaemia caused by?

A

Defective beta globin chains coded on chromosome 11

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19
Q

What are the 3 types of beta thalassaemia?

A
  • Thalassaemia minor
  • Thalassaemia intermedia
  • Thalassaemia major
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20
Q

What genotype is Thalassaemia Minor?

A

One abnormal gene + one normal gene
(Patients with beta thalassaemia minor = carriers of abnormally functioning beta globin gene

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21
Q

What does thalassaemia minor cause?

A

Mild microcytic anaemia

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22
Q

What is the genotype for thalassaemia intermedia?

A

2 abnormal copies of beta globin gene
* 2 defective genes
* One defective gene + one deletion gene

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23
Q

```

~~~

What does thalassaemia intermedia cause?

A

A more significant microcytic anaemia
(compared to thalassaemia minor)

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24
Q

What is the geneotype for thalassaemia major?

A

Homozygous for the deletion genes
(no functioning beta globin genes at all)

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25
Q

How does thalassaemia present in early childhood?

A
  • Severe anaemia
  • Failure to thrive
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26
Q

What thalassaemia major cause?

A
  • Severe microcytic anaemia
  • Splenomegaly
  • Bone deformities
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27
Q

What is the management for thalassaemia minor, intermedia, major?

A
  • Thalassaemia Minor → monitoring + no active treatment
  • Thalassaemia Intermedia → occassional blood transfusions + iron chelation
  • Thalassaemia major → regular transfusions + iron chelation + splenectomy + bone marrow (curative)
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28
Q

What is Von Willebrand disease (VWD)?

A

An inhereited deficiency, absence or malfunctioning of a glycoprotein called von Willebrand factor (VWF) → Causes abnormal + prolonged bleeding

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29
Q

What is von Willebrand factor used for?

A

Platelet adhesion + aggregation in damaged vessels

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30
Q

What are the 3 types of von Willebrand disease?

A
  • Type 1 → partial deficiency of VWF (most common, mildest)
  • Type 2 → reduced function of VWF
  • Type 3 → complete deficiency of VWF
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31
Q

What is are the clinical manifestations of von Willebrand disease?

A

Patients usually present with a Hx of unusually easy, prolonged or heavy bleeding
* Bleeding gums with brushing
* Nosebleeds (epistaxis)
* Easy bruising
* Heavy menstrual bleeding (menorrhagia)
* Heavy bleeding during and after surgical operations

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32
Q

What is the key question that you should ask in a family history when thinking about von Willebrand disease?

A

Any family history of **heavy bleeding (e.g. menorrhagia) or von Willebrand disease itself

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33
Q

What are the investigations for von Willebrand disease?

A

No single von Willebrand disease test
Diagnosis based on:
* History of abnormal bleeding
* FHx
* Bleeding assessment tools
* Laboratory investigations

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34
Q

When do you only manage Von Willebrand disease?

A

In response to:
* Significant bleeding
* Trauma (to stop bleeding)
* In preparation to operations (to prevent bleeding)

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35
Q

Name some forms of management for von Willebrand disease

A
  • Desmopressin (stimulates the release of vWF from endothelial cells)
  • Von Willebrand factor infusion
  • Factor VIII + von Willebrand factor infusion
  • Tranexamic acid

For heavy menstrual periods:
* Tranexamic acid
* Mefenamic acid
* Mirena coil
* Hysterectomy

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36
Q

What is immune thrombocytopenic purpura (ITP)?

A

ITP = a condition where antibodies are created against platelets → leads to their destruction + low platelet count (thrombocytopenia)

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37
Q

How does ITP usually present?

A

Purpura
(non-blanching lesions caused by bleeding under the skin)

38
Q

What is the managment for ITP?

A

Management:
* Prednisolone (steroids)
* IV immunoglobulins
* Thrombopoietin receptor agonists (e.g., avatrombopag)
* Rituximab (a monoclonal antibody that targets B cells)
* Splenectomy

39
Q

What is Haemophilia (A and B)?

A

Severe inherited bleeding disorders

40
Q

What is haemophilia A caused by?

A

Haemophilia A = caused by a deficiency of factor VIII

A = Ayyyyyyy-tt

41
Q

What is haemophilia B caused by?

A

Haemophilia B = caused by a deficiency in factor IX

B 9 (be mine)….trying

42
Q

What inheritence pattern does haemophilia A and B follow?

A

X-linked recessive diseases
(All X chromosomes need to have the abnormal gene to have haemophilia)
Since X-linked:
* Males → when they inherit 1 copy → affected
* Females → inherit 1 copy → asymptomatic carrier; inherit 2 copies → symptomatic

43
Q

Since haemophilia is X-linked recessive, what gender does the condition affect more?

A

Haemophilia = affects primarily males

44
Q

Most cases of haemophilia present in neonates or early childhood. How does haemophilia occur in neonates?

A
  • Intracranial haemorrhage
  • Haematomas
  • Cord bleeding
45
Q

What can happen to the joints and muscles in people with haemophilia?

A

Bleeding into the:
* Joints (haemarthrosis) e.g. ankle, knee, elbow → joint damage + deformity
* Muscles → causes compartment syndrome

46
Q

What are patients with haemophilia at risk of?

Very basic question

A
  • Excess bleeding in response to minor trauma
  • Sponatenous bleeding without trauma
47
Q

Apart from the joints and muscles, where can bleeding occur in patients with haemophilia?

A
  • Oral mucosa
  • Nosebleeds (epistaxis)
  • Gastrointestinal tract
  • Urinary tract → haematuria
  • Intracranial haemorrhage
  • Surgical wounds
48
Q

What investigations do you request for haemophilia?

A
  • Bleeding scores
  • Coagulation factor assays
  • Genetic testing
49
Q

What is the management for haemophilia A and B?

A

Regularly or in response to bleeding (via IV):
* Haemophilia A → factor VIII
* Haemophilia B → factor IX

A complication is the formation of antibodies (inhibitors) against the treatment → resulting in it becoming ineffective

50
Q

What is sickle cell anaemia?

A

Genetic condition that causes sickle (cresent) shaped RBCs

51
Q

What does sickle cell anaemia do to the RBCs?

A

Sickle shaped → more fragile → easily destroyed
Causing haemolytic anaemia

52
Q

What type of anaemia does sickle cell anaemia cause?

A

Haemolytic anaemia

53
Q

What are patients with sickle cell anaemia prone to?

A

Sickle cell crises

54
Q

When in gestation does production of fetal haemoglobin (HbF) decrease and adult haemoglobin (HbA) increase?

A

32-36 weeks gestation
(Gradual transition from HbF to HbA)

55
Q

At birth what percentage of HbF is left?

A

5O% HbF
(50% HbA)

At 6 months very little HbF is left

56
Q

What variant of haemoglobin is present in sickle cell anaemia?

A

Abnormal variant called haemophilia S (HbS)
(results in sickle-shaped RBCs)

57
Q

What inheritance pattern does sickle cell anaemia follow and which chromosome?

A

Autosomal recessive
Affects the gene for beta-globin
Chromosome 11

58
Q

Since sickle cell anaemia is autosomal recessive, what happens when people inherit one or two copies of HbS?

A
  • 1 copy → sickle cell trait → usually asymptomatic carriers
  • 2 copies → sickle-cell disease
59
Q

Why is the sickle cell trait more common in area like Africa, India, Middle East and the Caribbean?

A

There is a selective advantage → having the sickle cell trait makes them more likely to survive MALARIA → it is then more likely to be passed on

60
Q

When is sickle cell anaemia screened for?

A
  • Newborn blood spot (around 5 dats of age)
  • Pregnant women at high risk of being carriers of HbS are offered testing
61
Q

Name 4 complications of sickle cell anaemia

A
  • Anaemia
  • Increased risk of infection
  • Chronic kidney disease
  • Sickle cell crises
  • Acute chest syndrome
  • Stroke
  • Avascular necrosis in large joints such as the hip
  • Pulmonary hypertension
  • Gallstones
  • Priapism (painful and persistent penile erections)
62
Q

What are sickle cell crises?

A

A spectrum of acute exacerbations caused by sickle cell disease
(mild to life-threatening)

63
Q

What are sickle cell crises caused by?

A
  • Spontaneously
    Or triggered by:
  • Dehydration
  • Infection
  • Stress
  • Cold weather
64
Q

What is the treatment for a sickle cell crisis?

A

No sepcifc treatment → managed supportively
* Low threshold for admission to hospital
* Treating infections that may have triggered the crisis
* Keep warm
* Good hydration (IV fluids may be required)
* Analgesia (NSAIDs should be avoided where there is renal impairment)

65
Q

What is a vaso-occlusive crisis (VOC)?

A

AKA Painful crisis in sickle cell anaemia
* Sickle-shaped RBCs = clog capillaries → causing distal ischaemia

Typically presents as:
* Pain + swelling in hands + feet (also chest, back, other areas)
* Can be asssociated with fever

66
Q

What is the urological emergency caused by a vaso-occlusive crisis in a patient with sickle cell anaemia?

A

Priapism
* Trapping of blood in the penis → causing persistent + painful erection
* Treated by aspirating blood from the penis

67
Q

What is a splenic sequestration crisis?

A

In a patient with sickle cell anaemia → RBCs blocking the blood flow within the spleen → emergency

Presents as:
* Acutely enlarged + painful spleen

Blood pooling in the spleen → can lead to severe anaemia + hypovolaemic shock

68
Q

What is the management for splemic sequestration crisis?

A

Blood transfusions + fluid resuscitation→ to treat anaemia + shock

Splenectomy → preventative, used in recurrent cases

69
Q

What are the complications of splenic sequestration crisis?

A

Splenic sequestration crisis → splenic infarction → hyposlenism → susceptibility to infections (particularly encapsulated bacteria) (Streptcoccus pneumoniae + Haemophilus influenzae)

70
Q

What is an aplastic crisis in a patient with sickle cell anaemia?

A

The temporary absence of the creation of new RBCs

71
Q

What virus usually triggers an aplastic crisis in a patient with sickle cell anaemia?

A

Parvovirus B19

72
Q

What does aplastic crisis lead to?
How is it treated?

A

Aplastic crisis:
* Leads to significant anaemia (aplastic anaemia)
* Management → supportive (blood transfusions if necessary) → usually resolces spontaneously within a week

73
Q

What is acute chest syndrome in sickle cell anaemia?

A

Acute chest syndrome = vessels in the lungs become clogged with RBCs → medical emergency (high mortality)

Presents:
* Fever, SOB, chest pain, cough, hypoxia

74
Q

What will a CXR show in an acute chest syndrome in a person with sickle cell anaemia?

A

Pulmonary infiltrates

75
Q

What is the management for an acute chest syndrome in a person with sickle cell anaemia (a sickle cell crisis)?

A
  • Analgesia
  • Good hydration (IV fluids may be required)
  • Antibiotics or antivirals for infection
  • Blood transfusions for anaemia
  • Incentive spirometry using a machine that encourages effective and deep breathing
  • Respiratory support with oxygen, non-invasive ventilation or mechanical ventilation
76
Q

What is the general management for sickle cell disease?

A
  • Avoid triggers for crises, such as dehydration
  • Up-to-date vaccinations
  • Antibiotic prophylaxis to protect against infection, typically with penicillin V (phenoxymethylpenicillin)
  • Hydroxycarbamide (stimulates HbF)
  • Crizanlizumab
  • Blood transfusions for severe anaemia
  • Bone marrow transplant can be curative
77
Q

What drug stimulates the production of HbF in sickle cell anaemia?

A

Hydroxycarbamide
HbF does not lead to sickling (unlike HbS)
It reduces vaso-occulsive crises → improves anaemia + extends lifespan

78
Q

What drug (a monoclonal antibody) targets P-selectin (adhesion molecule) on endothelial cells + platelets used in sickle cell anaemia to prevent the RBCs sticking to blood vessels → reducing vaso-occulsive crises?

A

Crizanlizumab

79
Q

What is haemolytic disease of the newborn?

A

The incompatibility between the rhesus antigens on the surface of RBCs of the mother + fetus
Causes haemolysis (RBCs breaking down) + jaundice in the neonate

80
Q

What is the most important antigen within the rhesus blood group system?

A

Rhesus D antigen

81
Q

What happens when a mother who is rhesus D negative carries their first fetus that is rhesus D positive?

A

Fetal blood finds its way into her bloodstream → fetal RBCs display rhesus D antigen → mothers immune system will recognise it as foreign → produce antibodies against it

Mother becomes sensitised to rhesus D antigens
(Does not usually causes problems)

82
Q

Why is a second pregnancy when the mother is rhesus D neg and the baby is rhesus D positive a problem?

A

The mothers anti-D antibodies (acquired suring sensitisation during first pregnancy) → can cross the placenta into the fetus → is fetus is rhesus D positive → these antibodes = attach themselves to the fetal RBCs → causing the fetus’ immune system to attack its own RBCs

Leads to haemolysis → causing **anaemia + high bilirubin levels ** → leading to haemolytic disease of the newborn

83
Q

What is the investigation used to test for immune haemolytic anaemia → testing for haemolytic disease of the newborn?

A

Direct Coombs test (DCT)

84
Q

=

What is the management for the 3 types of beta thalassaemia?

A
  • Thalassaemia Minor: monitoring + no active treatment
  • Thalassaemia Intermedia: blood transfusions + iron chelation
  • Thalassaemia major: regular transfusions + iron chelation + splenectomy + bone marrow (curative)
85
Q

What is fanconi anaemia?

A

Rare inherited genetic disorder that primarily affects the bone marrow → leading to decreased production of all blood cells

86
Q

Does fanconi anaemia result in pancytopenia?

A

Yes! Decreased production of:
* RBCs (anaemia)
* WBCs (leukopenia)
* Platelets (thrombocytopenia)
Results in **fatigue, increased susceptibility to infections, easy bruising/bleeding **

87
Q

What are the clinical manifestations for fanconi anaemia?

A
  • **Thumb, arm, kidney malformations **
  • Short stature
  • Skin pigmentation changes
  • Skeletal abnormalities
88
Q

A patient has fanconi anaemia, what cancers are they at higher risk of developing?

A
  • Acute myeloid leukaemia (AML)
  • Head + neck cancer
  • GI cancer
  • Gynaecological cancers
89
Q

What are the management options for fanconi anaemia?

A
  • Bone marrow transplant (haematopoietic stem cell transplant) → replace defectove bone marrow cells
  • Medications (symptoms + complications) → growth factors to stimulate blood cell production + antibiotics to prevent infections
  • Androgens → stimulates RBC + platelet production → alleviates some symptoms of anaemia + thrombocytopenia
90
Q

A young child has a malformation with his thumb, he is short, is looking quite pale. You suspect he has fanconi anaemia, what investigations should you request?

A
  • Complete blood count (CBC) → pancytopenia
  • Bone marrow aspiration + biopsy
  • Gold standard: Chromosome breakage test → FA will show increased chromosome breakage
  • Genetic testing → most common genes FANCA, FANCC, FANCD2
  • Cancer screening

Phase 3a Paediatrics (13 decks)

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