Haem: Leukaemia Flashcards

1
Q

Define Acute Leukaemia

A

Neoplastic process affecting blood precursor cells (blast cells)

“Acute”: progressing rapidly, resulting in excess immature blood cells, and fatal

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2
Q

Pathoneumonic sign of Acute leukaemia when analysing bone marrow

A

Immature blast cells >20% of bone marrow cells

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3
Q

2 types of acute leukaemia

A

Acute Lymphocytic Leukaemia
Mutations in lymphoblast cell

Acute Myeloid Leukaemia
Mutations in the pluripotent haematopoetic stem cell OR multipotent myeloid stem cell

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4
Q

Clinical features seen in all types of Acute leukaemia

A

Bone Marrow Failure
- Anaemia (signs/sx of anaemia)
- Infection (neutropenia)
- Bleeding (thrombocytopenia)

Organ Infiltration of blast cells
- Hepatosplenomegaly
- Lymphadenopathy (ALL>AML)
- Others: Bone (ALL>AML), CNS (ALL>AML), Skin, Gums

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5
Q

Aetiology of Acute Leukaemias

A

Most times it is unknown however chromosome aberrations are commonly implicated:
- Duplication → resulting in increased copies of proto-oncogenes
- Inversion/Translocation → resutling in fusion genes which are pro-oncogenic
- Chromosomal loss → loss of tumour suppressor genes

Other commonly implicated aetiological factors:
- Ionising radiation (leading to DNA mutations)
- Cytotoxic drugs (leading to DNA mutations)
- Down’s Syndrome (AML>ALL)

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6
Q

2 Types of DNA abnormalities required for leukaemogenesis

A

Type 1: Promote cell proliferation

Type 2: Block cell differentiation

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7
Q

How do you diagnose Acute leukaemia

A
  1. Morphology of cells: increased blast cells, Auer rodes (AML!!)
  2. Immunophenotyping: differentiates between AML and ALL through CD receptors as well as ALL B-cell or T-cell predominent
  3. Cytogenics: identify chromosomal translocations for specific targetted treatment (e.g. Philadelphia chromosome in ALL)
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8
Q

Differentiating between ALL and AML:
Epidemiology

A
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9
Q

Differentiating between ALL and AML:
Clinical Features

A
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10
Q

Differentiating between ALL and AML:
Investigations

A
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11
Q

Differentiating between ALL and AML:
Management

A
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12
Q

Chronic Myeloid Leukaemia
Define and outline which cell carries leukaemogenic mutation

A

Myeloproliferative disease - with mutations in haematopoetic stem cell. Haematopoetic stem cell mutations (commonly the philadelphia chromosome) steer it into going down the myeloid differentiation pathway.

Unlike acute leukaemia, in chronic leukaemia you have partial maturation.

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13
Q

Chronic Myeloid Leukaemia
Age of onset

A

Middle-aged → 40-60s

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14
Q

Chronic Myeloid Leukaemia
Clinical feature

A

CLASSIC CLINICAL VIGNETTE:
Present feeling unwell, weight loss, recurrent infections and easy bruising.
On examination → MASSIVE splenomegaly (EXAM BUZZWORD)
Bloods → neutrophilia!!

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15
Q

Chronic Myeloid Leukaemia
Investigations when suspecting CML

A

FBC:
- Massively elevated WBC (50-500x109)
- Neutrophilia
- Basophilia

Blood film:
- Neutrophilia
- Basophilia
- Myelocytes (if you see myeloblasts you are thinking more acute CML)
→ biphasic peak where there is increased myelocytes and basophils/neutrophils

Bone Marrow Biopsy
- hypercellular BM with myelocytes (NOT myeloblasts) and mature granulocytic cells.
- myelobasts at <5% (unless in acute crisis)

FISH
- Philadelphia chromosome +ve in 80% of cases (translocation 9;22)

RQ-PCR
- BCR-ABL fusion gene (arising from the philadelphia chromosome)

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16
Q

Chronic Myeloid Leukaemia
Explain how the philadelphia chromosome contributes to the pathogenesis of CML

A

The philadelphia chromosome arises from the translocation between chromosomes 9 and 22.
This translocation creates a fusion gene: BCR-ABL
- ABL codes for a tyrosine kinase. TK’s are crucial for cell growth and division and therefore are not always expressed.
- BCR is a housekeeping gene. It is always being expressed.
→ This fusion gene, where BCR is first results in the constant expression of ABL.
→ Therefore resulting in increased TK activity resulting in increased cellular proliferation = leukaemia.

It is also thought that BCR-ABL expression in haematopoetic stem cells, steers them towards the myeloid lineage.

17
Q

Chronic Myeloid Leukaemia
Outline the different stages of CML and how they are distinguished

A
18
Q

Chronic Myeloid Leukaemia
How is CML treatment response monitored

A
19
Q

Chronic Myeloid Leukaemia
Outline the treatment regime for CML (in chronic phase, Ph +ve)

A

TYROSINE KINASE INHIBITORS:
1. Imatinib
2. Rasatinib
3. Bosutinib

Failure of response in 12 months OR complete response but resistance acquired (escape mutations) you move to next generation of tyroskine kinase inhibitors. If all 3 fail consider allogenic stem cell transplant.

20
Q

Chronic Myeloid Leukaemia
Outline the benefits of Tyrosine kinase inhibitor therapy

A
  • Decreased in mortality (annual mortality 2%)
  • 95% 5 year survival
21
Q

Chronic Lymphocytic Leukaemia
Definition and which cell is targeted

A

Lymphoproliferative disease (similiar to lymphoma)

Arising from mutations in naive B cells or Post-germinal centre memory B cells where there is intereference of B cell receptors activating specific tyrosine kinases (e.g. Bruton’s TK preventing maturation, and BCL2 which prevent apoptosis)

22
Q

Chronic Lymphocytic Leukaemia
Distinguish CLL and Small Lymphocytic Lymphoma (SLL)

A

Essentially same disease with slightly different presentations.
CLL is primarily seen in bone marrow while SLL is primarily seen in clusters of B-cell malignant cells in lymph nodes (thought to be the case in mature CLL)

23
Q

Chronic Lymphocytic Leukaemia
Epidemiology

A

M>F
Elderly (median 65-70)

24
Q

Chronic Lymphocytic Leukaemia
Clinical features

A

Often asymptomatic and incidental finding in blood result = lymphocytosis (commonest cause of lymphocytosis!!!!!)

May also present with
- Symmetrical painless lymphadenopathy
- BM failure: anaemia, thrombocytopaenia, recurrent infections (infections account for 50% of deaths in CLL)
- B-cell systemic symptoms: FLAWS
- Hepatosplenomegaly

25
Q

Chronic Lymphocytic Leukaemia
A sudden deterioration in CLL can be explained by?

A

Richter’s transformation - whereby CLL transforms into a more aggressive large cell lymphoma (Diffuse large B-cell lymphoma).
This can be accounted for by subsequent mutation resulting in this transformation.

26
Q

Chronic Lymphocytic Leukaemia
What syndrome is CLL associated with?

A

Evan’s Syndrome - associated with autoimmunity involving two or more cytopaenias (AIHA, ITP)

27
Q

Chronic Lymphocytic Leukaemia
Investigation findings

A

FBC
- Elevated WBC count (high % of WBC composed of lymphocytes)
- Low serum immunoglobulin

Blood film
- Smear cells

Flow Cytometry
- CD5+ , CD19+ and CD23+ monoclonal B cell population

28
Q

Chronic Lymphocytic Leukaemia
Differentiate the monoclonal population in a healthy patient and a patient with CLL

A

Healthy patients’ mature B-cells: CD19 +ve but CD5 -ve
Healthy patients’ mature T-cells: CD19 -ve but CD5 +ve

CLL patients monoloclonal population: CD19 +ve and CD5 +ve

29
Q

Chronic Lymphocytic Leukaemia
Outline the staging used in CLL

A

Binet Staging: A,B,C

Stage A:
- High WBC
- <3 groups of enlarged lymph nodes
- Usually no treatment required - watchful waiting

Stage B:
- >3 groups of enlarged lymph nodes

Stage C:
Anaemia or thrombocytopaenia (bone marrow failure)

30
Q

Chronic Lymphocytic Leukaemia
Prognostic factors used in CLL

A

Cytogenics - looking for a collection of common genetic abnormalities screened for that convey worse prognosis:
- 17p (TP53) deletion → worse prognosis as it is deletion of p53 tumour suppressor gene

Immunoglobulin gene mutation status:
- IgH unmutated → worse prognosis

Binet staging can be used for prognosis as well

31
Q

Chronic Lymphocytic Leukaemia
Treatment

A

Asymptomatic, Slowly progressive disease, Elderly and frail:
1. Watchful waiting
1. Supportive treatment: vaccinations (not live), prophylaxis of antivirals or antibiotics
young patients can be cured with allogenic stem cell transplant

If any of the below → Indication for chemotherapy
- Progressive lymphocytosis (doubling <6months)
- Progressive BM failure
- Massive/progressive hepatosplenomeagly
- Systemic sx

TREATMENT:
1) chemotherapy - FCR
OR - increasingly more so:
1) Targeted therapy = BTK inhibitor (ibrutinib - inhibits B cell production) or BCL2 inhibitor (venetoclax - induces apoptotic pathway and good response in p53 mutated CLL patients)

32
Q

Important complication of using venetoclax therapy in CLL

A

tumour lysis syndrome