Chronic myeloproliferative disorders and chronic myeloid leukaemia Flashcards Preview

Clinical Pathology > Chronic myeloproliferative disorders and chronic myeloid leukaemia > Flashcards

Flashcards in Chronic myeloproliferative disorders and chronic myeloid leukaemia Deck (42):
1

What are chronic myeloproliferative disorders?

- Malignant clonal stem cell disorders of the bone marrow.

1. Polycythaemia Vera
2. Essential thrombocytosis
3. Idiopathic Myelofibrosis

2

What percentage of chronic myeloproliferative disorders transform into acute leukaemia?

10%

3

What is polycythaemia vera?

- Increased red cells, +/-neutrophils, +/-platelets
- Distinguish from secondary polycythaemias and relative polycythaemia

4

What is essential thrombocythaemia?

- Increased platelets
- Distinguish from reactive thrombocytosis

5

What is myelofibrosis?

- Variable cytopenias with a large spleen
- Distinguish from other causes of splenomegaly

6

What is the epidemiology of polycythaemia vera?

All ages, peak at 50-70 years

7

What are the signs and symptoms of polycythaemia vera?

- Itching (aquagenic- hot baths)
- Plethoric face
- Headache, muzziness,
- General malaise
- Tinnitus
- Peptic ulcer
- Gout
- Gangrene of the toes
- Engorged retinal veins
- Splenomegaly

8

How is polycythaemia vera diagnosed?

- Persistent increased Hb/hct >0.5

- Is it:
-- relative V absolute polycthaemia
-- Primary V Secondary polycythaemia

- Detailed History and Examination

- 1st line tests
-- FBC
-- Ferritn
-- Epo level
-- UE/LFT

9

What is the cause if primary polycythaemia?

Polycythaemia vera

10

What are the causes of secondary polycythaemia?

Central hypoxic process
- Chronic lung disease
- Right-to-left shunts Heart Disease
- Carbon monoxide poisoning
- Smoker
- High Altitude

Renal disease

EPO production Tumours

Drug associated
- Treatment with androgen preparations
- Postrenal transplant erythrocytosis

Congenital
- High oxygen-affinity haemoglobin
- Erythropoeitin receptor-mediated

Idiopathic erythrocytosis

11

What second line tests should be performed in cases of suspected polycythaemia?

Epo elevated
1. CXR
2. ABG
3. USS abdomen

Epo normal or low
1. JAK2 mutation
2. Bone marrow examination
3. EXON12 mutation

12

For which cytokine receptors is JAK the signalling pathway?

GM-CSF
GCSF
EPO
TPO
SCF
interleukins

13

What are the features of the JAK2 mutation?

- Occurs in the JH2 domain (inactive)
- G-to-T mutation at nucleotide 1849
- Phenylalanine for valine at 617 in protein (V617F)
- Destroys a BsaXI site
- Patients may be heterozygous or homozygous

14

The presence of a JAK2 V617F mutation
in peripheral blood DNA is diagnostic of what?

A myeloproliferative disorder?

15

What is the treatment of polycythaemia vera?

- Venesection - aim for a haematocrit of

16

What is the prognosis for polycythaemia vera?

- Good - 15 year median survival
- Risk developing AML
- Risk developing Myelofibrosis

17

What is primary essential thrombocytosis (ET)?

A disease in which abnormal cells in the bone marrow cause an increase in platelets.

18

What is reactive thrombocytosis?

An elevated platelet count (> 450,000/μL) that develops secondary to another disorder.

19

What are the causes of reactive thrombocytosis?

- Surgery
- Infection
- Inflammation
- Malignancy
- Iron deficiency
- Hyposplenism
- Haemolysis
- Drug induced (steroids, adrenaline, TPO mimetics)
- Rebound post chemo

20

How would you perform a thrombocytosis investigation?

- Good history / examination IMPORTANT (e.g.recent normal count prior to surgery)
- Persistent Platelets >450 x109/L

1st line investigations
1. FBC and film
2. Ferritin
3. CRP
4. CXR
5. ESR

21

What second-line investigations would you perform in suspected thrombocytosis?

- JAK2
- CALR
- ? Bone marrow biopsy
- Extensive search for secondary cause

22

What is the CALR mutation?

- Calreticulin mutation
- cell signalling protein produced in ER (endoplasmic Reticulin)
- Mutation in EXON 9 of gene
- Found in Myeloid progenitors in ET
- Mechanism of action unknown at present but may activate cell signal pathways
- found in upto 90% of JAK2 negative ET

23

What percentage of ET patients have a JAK2 mutation?

50%

24

What percentage of ET patients have a CALR mutation?

45%

25

What is the treatment of ET?

- Assess thrombotic risk
-- Age
-- Hypertension
-- Diabetes
-- Platelet count >1500
-- History of thrombosis

- Antiplatelet treatment
-- Aspirin 75mg daily

- Cytoreduction (only if High risk)
-- 1 or more risk factors

26

What drugs are used for cytoreduction?

- Hydroxycarbamide
- Interferon
- Anagrelide
- P32

27

What is the prognosis for ET?

- Overall excellent 20 year median survival
- Risk of AML or Myelofibrosis
- CALR mutated have lower thrombosis risk

28

What is myelofibrosis?

The proliferation of an abnormal clone of haematopoietic stem cells in the bone marrow and other sites results in fibrosis, or the replacement of the marrow with scar tissue.

29

What is the presentation of myelofibrosis?

- Pancytopenia
- B symptoms
- Massive splenomegaly

30

What investigations should you perform if you suspect myelofibrosis?

- FBC and film
- Haematinics

31

How is the diagnosis of myelofibrosis reached?

- Blood film
- Bone marrow results
- JAK2 mutation 50%
- CALR mutation 30%

32

What are the possible causes of splenomegaly?

- C Cancer
- H Haematological - Myelofibrosis, CML
- I Infection - Schistosomiasis,malaria
- C Congestion - Liver disease / portal
- A Autoimmune- haemolysis
- G Glycogen storage disorders
- O Other - Amyloid, etc

33

What is the treatment for myelofibrosis?

- Supportive care
- JAK2 Inhibitors
- Bone marrow Transplant

34

What is the prognosis for myelofibrosis?

- Poor
- Median survival 5 years

35

What is the epidemiology of chronic myeloid leukaemia?

- Rare: Aproximately 1 per 100,000 per year
-

36

What are the characteristics of chronic myeloid leukaemia?

- Leucocytosis+++
- Leucoerythroblastic blood picture
- Anaemia
- Splenomegaly

37

What are the symptoms of CML and their causes?

- Abdominal discomfort: Splenomegaly
- Abdominal pain: Splenic infarction
- Fatigue: Anaemia, catabolic state
- Venous occlusion: Retinal vein, DVT, priapism
- Gout: Hyperuricaemia

38

What is the treatment for CML?

1. Chronic phase:
- Low dose oral cytotoxic drugs (busulphan, hydroxycarbamide)
- Interferon

2. Acute leukaemic transformation/blast crisis
- Myeloid and Lymphoid types
- Intensive chemotherapy, poor outcome

3. Allogeneic bone marrow transplantation
- Curative in ~ 50% of patients

39

What is Gleevec (imatinib)?

A small molecule specifically designed to block the active site in the bcr-abl tyrosine kinase.

40

What is the cause of imatinib resistance?

Activating loop mutations in BCR-ABL confer resistance and loss of disease control.

41

What new tyrosine kinase inhibitors are available?

Nilotinib and Dasatinib

42

What are the main features of CML (ie a summary of key points)?

- Pluripotent stem cell disorder
- Defined by the t(9;22) translocation
- Driven by BCR-ABL fusion tyrosine kinase
- Chronic phase followed by acute transformation
- Designer molecule treatment (imatinib) has proved highly successful
- BCR-ABL mutations confer resistance to imatinib.

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