Haem: Leukaemia Flashcards

1
Q

What is leukaemia?

A

A cancer of immature WBCs.

This is the most common type of cancer found in children (31% of all childhood cancer cases).

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2
Q

How can leukaemia be classified?

A

1) How rapidly they progress: acute or chronic

2) Cell line that is affected: myeloid or lymphoid

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3
Q

Aetiology of leukaemia?

A

Leukaemia involves abnormal proliferation and differentiation of leucocytes or their precursor cells.

Most cases of leukaemia are caused by de novo mutations (new mutations which are not inherited). However, there are also genetic syndromes which predispose children to leukaemia.

A genetic mutation in one of the precursor cells in the bone marrow leads to excessive production of a single type of abnormal WBC.

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4
Q

Describe haematopoiesis and development of leukaemia

A

1) Multipotent haematopoietic stem cell, gives rise to:

2) Common lymphoid progenitor or common myeloid progenitor

These progenitor cells differentiate further to produce their respective lymphoid or myeloid cell populations.

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5
Q

Aetiology of chronic vs acute leukaemias?

A

Acute leukaemias result from failure of lymphoid or myeloid progenitor cells to differentiate, with resultant uncontrolled proliferation of these immature blast cells.

Chronic leukaemias result from the uncontrolled proliferation of cells at a later stage of differentiation.

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6
Q

What are the 4 types of leukaemias seen in children?

From most to least common:

A

1) Acute lymphoblastic leukaemia (ALL)

2) Acute myeloid leukaemia (AML)

3) Chronic myeloid leukaemia (CML)

4) Chronic lymphocytic leukaemia

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7
Q

What is the most common type of leukaemia in children?

A

Acute lymphoblastic leukaemia (ALL) - approx 75% of childhood leukaemia diagnoses

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8
Q

What does ALL develop as a result of?

A

Abnormal abnormal proliferation and failed differentiation of B or T lymphoid progenitor cells.

The uncontrolled proliferation of these immature lymphocytes (lymphoblasts) within bone marrow prevents normal haematopoiesis, and the abnormal blasts can spread to infiltrate other organs.

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9
Q

Haematopoesis of a common lymphoid progenitor?

A

Look up diagram.

1) Common lymphoid progenitor

2) Natural killer cell or small lymphocyte

3) Small lymphocyte develops into T or B lymphocyte

4) B lymphocyte develops into plasma cell

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10
Q

What does acute myeloid leukaemia (AML) result from?

A

AML results from uncontrolled proliferation and failed differentiation of immature blast cells of myeloid lineage.

These blasts disrupt normal haematopoiesis in the bone marrow and can infiltrate extramedullary organs.

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11
Q

Chronic myeloid leukaemia (CML) is less common in children. What is the median age of diagnosis?

A

60-65 y/o

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12
Q

CML vs AML?

A

CML develops from blood cells of the myeloid lineage, which are more mature than those seen in AML

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13
Q

What genetic abnormality is seen in 90% of CML cases?

A

Philadelphia chromosome

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14
Q

What is the Philadelphia chromosome?

A

This results from a translocation between chromosomes 9 and 22, t(9;22).

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15
Q

What age does ALL peak?

A

2-3 y/o

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16
Q

What age does AML peak?

A

<2 y/o

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17
Q

In leukaemia, the excessive production of a single type of cell can lead to suppression of the other cell lines, causing underproduction of other cell types.

What does this result in?

A

Pancytopenia: anaemia, leukopenia & thrombocytopenia

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18
Q

Describe how CML can progress

A

Chronic phase –> accelerated phase (with an increase in immature blast cells) –> blast crisis phase (≥30% presence of blast cells in the bone marrow or peripheral blood (or extramedullary infiltration by blast cells).

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19
Q

What are some risk factors for leukaemia?

A

1) Genetic syndromes

2) Exposure to ionising radiation

3) Pesticides

4) Viruses e.g. EBV, HIV

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20
Q

What are 5 genetic syndromes which predispose individuals leukaemia?

A

1) Down’s syndrome

2) Fanconi anaemia

3) Li Fraumeni syndrome

4) Ataxia telangiectasia

5) Nijmegen breakage syndrome

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21
Q

How much more likely are patients with Down’s syndrome likely to develop ALL & AML?

A

30x more likely to develop ALL

150x more likely to develop AML

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22
Q

What is the characteristic leukaemia seen in Down’s syndrome?

A

M7 acute megakaryoblastic AML

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23
Q

What 2 viruses can predispose to leukaemia?

A

EBV & HIV

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24
Q

Symptoms of leukaemia?

A

Often vague and non-specific:

  • Fatigue and malaise
  • Bone and joint pain: particularly affecting the legs
  • SOB: caused by anaemia, mediastinal mass or infection
  • Dizziness and palpitations
  • Recurrent and/or severe infections
  • Fevers
  • Thrombocytopenia: bleeding tendency (epistaxis, bleeding gums), easy bruising, rashes
  • Lymphadenopathy
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25
Q

What are some typical clinical findings in leukaemia?

A
  • Weight loss
  • Skin: pallor, petechial rash, bruising
  • CVS: tachycardia, flow murmur
  • Abdomen: distension, hepatomegaly and/or splenomegaly
  • Lymphadenopathy
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26
Q

What are the red flag clinical features of suspected haematological malignancy in children (NICE)?

A

An urgent specialist assessment is required if any of the following red flag features are present:

1) Unexplained petechiae
2) Unexplained hepatosplenomegaly

An urgent FBC is required if any of the following red flag features are present:

1) Pallor
2) Persistent fatigue
3) Unexplained fever
4) Unexplained persistent infection
5) Generalised lymphadenopathy
6) Unexplained bruising or bleeding
7) Persistent/unexplained bone pain

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27
Q

Give some differentials for leukaemia

A

Infective: infectious mononucleosis, parvovirus B19

Malignant: lymphoma, rhabdomyosarcoma

Autoimmune: SLE, JIA

Haem: aplastic anaemia, fanconi anaemia

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28
Q

Relevant bedside investigations in leukaemia?

A

1) Obs
- fever: can indicate malignancy or infection
- tachycardia: infection or anaemia.

2) Urine dip: infection is an important differential diagnosis.

3) ECG:
- tachycardia
- baseline is useful before cardiotoxic chemotherapy

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29
Q

What lab investigations may be relevant in leukaemia?

A

1) FBC

2) Blood film

3) Coagulation profile

4) Baseline kidney and liver function

5) LDH & uric acid

6) Blood cultures: if presenting with fever/signs of infection.

7) G6PD

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30
Q

What may a FBC show in leukaemia?

A

1) Raised WCC due to blast cell proliferation

2) Pancyopenia will occur with bone marrow suppression (anaemia and thrombocytopenia are common, while WBC count may be variable)

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31
Q

What may a blood film show in leukaemia?

A

Shows the presence of blast cells.

Note - there may be a false negative if blasts are confined to bone marrow).

Blast cells should normally not be seen in peripheral blood, so this is highly suspicious for leukaemia if seen on microscopy.

32
Q

What may a cogulation profile show in leukaemia?

A

May be deranged or show disseminated intravascular coagulation (DIC).

33
Q

Why is a baseline kidney & liver function important in leukaemia?

A

These are needed prior to starting chemotherapy.

LFTs may indicate liver infiltration, and electrolytes can show complications of very high cell turnover such as tumour lysis syndrome (although this is usually seen post-chemotherapy).

34
Q

What may LDH & uric acid levels show in leukaemia?

A

Raised lactate dehydrogenase and uric acid occur with increased cell turnover.

35
Q

Why is G6PD level important in leukaemia?

A

G6PD deficiency should be identified before commencing rasburicase as it can result in a haemolytic crisis.

36
Q

What is rasburicase?

A

A drug given before and during chemotherapy to treat some types of cancer.

It can help to prevent tumour lysis syndrome.

36
Q

What imaging may be relevant in leukaemia?

A

1) CXR

2) Echocardiogram

37
Q

Why is a CXR relevant in leukaemia?

A

Extremely important to identify early if a MEDIASTINAL MASS is present before the child receives any anaesthetic.

A mediastinal mass may be present in T-cell lymphoblastic lymphoma, which overlaps with T-cell ALL.

Mediastinal mass can cause airway compromise, cardiovascular collapse, and death.

An X-ray may also show infection, enlarged nodes, and lytic bone lesions.

38
Q

Why is an echo relevant in leukaemia?

A

Important prior to starting cardiotoxic chemotherapies.

39
Q

Bone marrow aspiration and trephine biopsy are used for both diagnosis and monitoring in leukaemia.

What may a biopsy be used for?

A

1) Diagnosis (presence of ≥20% blasts)

2) Minimal residual disease analysis after treatment

3) Cytogenetics: detects chromosomal aberrations

4) Immunophenotyping: uses flow cytometry analysis to characterise the leukaemia blasts

40
Q

What % blasts in a bone marrow biopsy indicates leukaemia?

A

≥20%

41
Q

Role of cytogenetics in leukaemia?

A

Cytogenetics detects chromosomal abnormalities and is used for risk stratification, by categorising children into three risk groups (low, intermediate and high).

These are used to indicate prognosis and guide treatment.

42
Q

At the end of induction chemotherapy in leukaemia, what should the blast cell count be for patients to be classed as being in remission?

A

≤5%

Presence of residual disease (i.e. persistent leukaemic cells) indicates the need for more intensive chemotherapy.

43
Q

What are the two most widely known classification systems for leukaemia?

A

1) French-American-British (FAB)

2) World Health Organisation (WHO)

44
Q

What is the FAB classification for leukaemia based on?

A

Based on morphology (the appearance of cells under a microscope) and cytochemical staining of leukaemic cells.

45
Q

What is the WHO classification for leukaemia based on?

A

Uses cytogenetics (chromosomal analysis) and immunophenotyping (use of antibodies to detect white blood cell antigens).

46
Q

What is the mainstay of treatment in leukaemia?

A

Chemotherapy

47
Q

What are the 4 stages of chemo for ALL?

A

1) Induction

2) Consolidation and CNS treatment

3) Delayed intensification

4) Maintenance

48
Q

What is the induction phase of chemo for ALL?

A

What - An intensive phase lasting 4-6 weeks.

Purpose - Aims to destroy all leukaemic blast cells.

49
Q

To reduce the risk of tumour lysis syndrome in chemo for leukaemia, what can be given prior to induction?

A

Pre-phase treatment with hydration and allopurinol/rasburicase is given prior to chemo.

50
Q

What is the aim of the consolidation and CNS treatment stage of chemo for ALL?

A

Aim is to maintain remission.

Lumbar puncture with intrathecal methotrexate aims to prevent spread to the CNS.

51
Q

What can prevent spread to CNS in leukaemia?

A

Lumbar puncture with intrathecal methotrexate.

52
Q

What is the aim of the ‘delayed intensification’ stage of chemo for ALL?

A

To remove as many remaining blasts as possible prior to the maintenance phase.

53
Q

How long does treatment for ALL continue for in boys vs girls (i.e. the maintenance phase)?

A

Girls - 2 years

Boys - 3 years

This can involve oral or intravenous chemotherapy, steroids, and intrathecal treatments.

54
Q

Give 6 chemotherapy agents commonly used in ALL

A

1) Corticosteroids

2) Vincristine

3) Anthracyclines

4) Asparaginase

5) Cyclophosphamide

6) Cytarabine

55
Q

What are the 2 stages of chemo for AML?

A

1) Induction: intensive phase which aims to destroy all leukaemic cells.

2) Post-remission treatment: usually involves two further courses of chemotherapy, aiming to destroy residual cells and prevent a recurrence.

56
Q

What is repeated following chemo induction phase in AML to assess whether remission has been achieved?

A

Bone marrow biopsy

57
Q

Give 3 other treatments for leukaemia

A

1) Bone marrow transplant

2) Testicular radiotherapy: used for patients with testicular infiltration

3) CNS treatments: chemotherapy drugs may be injected intrathecally (via lumbar puncture)

58
Q

When is a bone marrow transplant used in leukaemia?

A

This is only used in patients with a high risk of disease recurrence, or with recurrence following standard chemotherapy.

59
Q

Give some early complications of leukaemia

A

1) Neutropenic sepsis

2) Thrombocytopenia: bleeding, stroke, haemorrhage (lung or gastrointestinal)

3) Blast cell lysis

4) Leucostasis: stroke, pulmonary oedema, heart failure

5) CNS infiltration: seizures, stroke

60
Q

What are the therapy-related complications of leukaemia?

A

1) Corticosteroid side effects: behavioural issues, weight gain

2) Neutropenic sepsis

3) Tumour lysis syndrome

4) Mucositis, gastrointestinal inflammation

5) Renal and hepatic toxicity

6) Neurotoxicity

7) VTE

8) Alopecia

61
Q

What are some long-term complications of leukaemia?

A

1) 2ary cancers

2) Avascular necrosis (a complication of high-dose steroids)

3) Cardiotoxicity (e.g. secondary to anthracycline treatment)

4) Reduced GH: short stature and obesity

5) Fertility issues

62
Q

Which chemo agent used in leukaemia can cause cardiotoxicity?

A

Anthracyclines e.g. doxorubicin

63
Q

What is tumour lysis synrome?

A

An oncological emergency caused by lysis of tumour cells, either due to chemotherapy treatment or sometimes spontaneously in highly proliferative tumours.

64
Q

What electrolyte imbalances are seen in tumour lysis syndrome?

A

1) hyperphosphataemia

2) hyperkalaemia

3) hypocalcaemia

4) hyperuricaemia

65
Q

What are the clinical manifestations of tumour lysis syndrome?

A

1) AKI

2) Cardiac arrhythmias

3) N&V

4) Seizures

66
Q

How can the risk of tumour lysis syndrome be reduced prior to chemo?

A

1) Hydration
2) Allopurinol
3) Rasburicase (may be used if white cell count is >50)

67
Q

When can rasburicase be used in prophylactic management of tumour lysis syndrome?

A

If WCC is >50

68
Q

Mechanism of rasburicase vs allopurinol in tumour lysis syndrome?

A

Rasburicase - actively breaks down the uric acid

Allopurinol - prevents uric acid production

69
Q

What does treatment of tumour lysis syndrome involve?

A
  • aggressive hydration
  • rasburicase or allopurinol
  • haemofiltration or dialysis
70
Q

What should always be EXCLUDED before giving rasburicase?

A

G6PD deficiency - as it increases the risk of haemolytic crisis.

71
Q

Prognosis of leukaemia?

A

79% 5 year survival rate.

The overall cure rate in ALL is now 85-90%.

72
Q

ALL can cause organomegaly (hepatomegaly (64%) or splenomegaly (61%)).

How may this present?

A

Can present with symptoms of anorexia, weight loss, abdominal pain or distension.

73
Q

How does lymphadenopathy typically present in ALL?

A

Most likely presents with a persistent or progressive, painless, firm, rubbery lymph node.

74
Q

What is the most common treatment for CML?

A

Tyrosine kinase inhibitors

75
Q
A