MYELOPROLIFERATIVE DISORDERS Flashcards Preview

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Flashcards in MYELOPROLIFERATIVE DISORDERS Deck (29):
1

What are the classic myeloproliferative disorders?

Non cancer:
Polycythaemia vera
Essential thrombocythaemia

Cancer:
Idiopathic myelofibrosis
(CML)

2

What defines polycythaemia?

Raised PCV (packed cell volume)

3

What are the upper limits of packed cell volume in men and women?

0.51 in men
0.48 in women

4

What are the causes of polycythaemia?

Primary
Polycytheamia vera
Familial (eg Chuvash polycythaemia)

Secondary
Chronic tissue hypoxia (eg COPD)
Ectopic EPO (eg renal disease or extrarenal neoplasms)
Endocrine causes (exogenous EPO and steroids, or endogenous syndromes such as Conn's and Cushing's)

5

What is the term used to describe a rise in packed cell volume without a rise in red cell mass and what is it caused by?

Apparent polycythaemia caused by a reduction in plasma volume

6

How might someone with suspected polycythaemia vera present?

History of occlusive vascular lesions (eg stroke, TIA, venous thrombosis)
Headache
Mental clouding
Facial redness
Itching
Abnormal bleeding
Gout

7

What investigations should be ordered for someone with suspected polycythaemia vera?

FBC
Red cell mass
Serum ferritin
Ultrasound to assess size of spleen
Investigations into causes of secondary polycythaemia such as EPO levels
Bone marrow cytogenic analysis

8

What would the full blood count of someone with polycythaemia vera show?

Raised WCC
Raised platelet
Raised PCV

9

Why is it useful to do a serum ferritin in someone with a normal PCV but in whom there are suspicions of polycythaemia?

Iron deficiency may mask raised PCV

10

How is someone with polycythaemia vera treated?

Repeated venesection to maintain PCV at less than 0.45
Low dose aspirin
Hydroxyurea or interferon-alpha can be used to maintain lower platelet count

11

How often is venesection performed in someone with polycythaemia vera?

Quite frequently at first but eventually every 6-10 weeks

12

What is the prognosis for someone diagnosed with polycythaemia vera?

Usually good
20% incidence of transformation to myelofibrosis and 5% to acute leukaemia

13

How is apparent polycythaemia treated?

Venesection only done in patients with increased risk of vascular complications for other reasons.

14

What is the central diagnosis feature of essential thrombocythaemia?

A persisting platelet count of more than 600x10^9/L

15

What are the causes of a rapid increase in platelet count?

Reactive thrombocytosis:
Infection
Malignancy
Inflammatory diseases
Haemorrhage
Iron deficiency
Post-surgery
Post-splenectomy
Myeloproliferative disorders
CML

16

What is the genetic mutation associated with the myeloproliferative disorders?

JAK2 V617F

17

What investigations should be performed in someone with suspected essential thrombocythaemia?

JAK2 V617F mutation
FBC
Blood film
ESR
CRP
Serum ferritin
Bone marrow aspirate
Trephine (bone marrow) histology

18

What might be seen in trephine (bone marrow) histology of someone with essential thrombocythaemia?

Clusters of large megakaryocytes

19

How might someone with essential thrombocythaemia present?

Microvascular occlusive events
Burning pain in extremities
Digital ischaemia
Major vascular occlusive events
Stroke
MI
Bleeding

20

What can essential thrombocythaemia transform into in a minority of patients?

Myelofibrosis
Acute leukaemia

21

How are patients with essential thrombocythaemia treated?

Daily low dose of aspirin
Hydroxyurea
Busulfan
Interferon-alpha (particularly useful in pregnancy)

22

What are the main features of idiopathic myelofibrosis?

Bone marrow fibrosis - replaced with reticulin
Extramedullary haemopoiesis - liver and spleen
Splenomegaly
Leucoerythroblastic picture (immature red and white blood cells)

23

How do patients with idiopathic myelofibrosis usually present?

Splenomegaly
Anaemia
Fatigue
Bleeding

Constitutional B symptoms may be present

24

Other than idiopathic myelofibrosis, what might cause a leucoerythroblastic blood film picture?

Bone marrow infiltration
Severe sepsis
Severe haemolysis
Sick neonate
Administration of haemopoietic growth factors
Acute or chronic leukaemia

25

What are the two phases of idiopathic myelofibrosis and what might an FBC in each phase show?

Proliferative phase - normal RCC or even raised, raised WCC, raised platelets
Cytopenic phase - reduced FBC

26

What is the median survival of symptomatic idiopathic myelofibrosis patients?

3 years

27

What are the treatment options for someone diagnosed with idiopathic myelofibrosis?

Bone marrow transplantation from a match. This cannot be performed in most patients (esp those over 50) due to the toxicity of the procedure
Supportive treatment such as blood transfusions are frequently given
Antifibrotic agents such as thalidomide may be given with varying success
Splenectomy may improve quality of life but not prognosis, by reducing need for transfusions
JAK2 inhibitors

28

Why might splenectomy be useful in improving quality of life of idiopathic myelofibrosis patients?

Reduce need for transfusions

29

What is the cause of death in people with idiopathic myelofibrosis?

Haemorrhage
Infection
Transformation to acute leukaemia
Iron overload from blood transfusions