Haematology 3s - myeloproliferative diseases Flashcards

1
Q

Normal haumatopoeisis is regulated by…?What do they interact with?

A

Growth factors e.g. EPO

These interact with receptors –> tyrosine kinase activation

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2
Q

An important enzyme in haemopoiesis

A

JAK

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3
Q

Which cells is JAK2 mainly implicated in?

A

Myeloid cells

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4
Q

Mutation in JAK…

A

Constitutive activation of the STAT pathway independent of cytokines binding to the receptor

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5
Q

Which mutation is diagnostic of PRV?

A

JAK2 V617F

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6
Q

What will some MPDs progress to?

A

Acute leukaemia

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7
Q

Name 3 myeloproliferative neoplasia which are BCR-ABL negative?

A

Polycythaemia rubra vera
Essential thrombocytosis
Myelofibrosis

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8
Q

How does blood from MPN patients behave on agar culture?

A

Cells will grow in absence of EPO or TPO

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9
Q

2 main features of MPNs?

Common presentations?

A

BM fibrosis

Increased proliferation of MATURE cells

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10
Q

2 mutations seen in MPNs?

A

JAK2 and Exon 12

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11
Q

Clinical features of PRV

A
Sx of hyperviscocity
Increased histamine release --> aquagenic pruritis and peptic ulceration
Variable splenomegaly
Erythromelalgia
Thrombosis (Arterial)
Retinal vein engorgement
Gout
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12
Q

Epidemiology for PRV - age? sex?

A

M>F

>60

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13
Q

Haem Ix in PRV?

A
High Hb
High HCT
High MCV
High plts
NO circulating immature cells
High plasma volume
Low EPO
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14
Q

Specific investigations for PRV

A

BM trephine biopsy (increased cellularity, no fat spaces, reticulin fibrosis and megakaryocyte abnormality)

JAK2 V617F MUTATION = DIAGNOSTIC

Blood volume: measured by isotope dilution

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15
Q

Dx if pt has raised HCt with an JAK2 Exon 12 mutation?

A

Idiopathic erythrocytosis

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16
Q

If negative for JAK2 muataion and have polycythaemia

A

Could be pseudopolycythaemia, true polycythaemia i.e. secondary to EPO secretion

17
Q

Current diagnostic criteria for PRV

A

Raised red cell production and increased platelets

JAK2 V617F mutation

18
Q

Treatment of PRV

A

hCT <45% and plt <400x10^9

Venesection
hydroxycarbamide + aspirin

19
Q

Features of idiopathic erythrocytosis

A
isolated erythrocytosis
Less likely to transform in to MF or AML
ABSENCE OF JAK2 V617F MUTATION
Exon 12 mutation OF JAK2
Low EPO
Treated with venesection only
20
Q

Prognosis of PRV vs idiopathic erythrocytosis

A

PRV most survive 10 years (death by thrombosis, leukaemia, myelofibrosis)
Erythrocytosis: no adverse prognosis if Hct is maintained

21
Q

What is the disorder?

  • 2 age peaks at 30 and 55 yo
  • BM dominated by megakaryocytes
  • Blood film = large platelets
  • Plt count >600*10^9
A

Essential thrombocythaemia

22
Q

What % of pts with ET have JAK2 mutation

A

50% (some also have TPO mutation)

23
Q

Treatment of ET

A
  • Aspirin (prevent thrombosis)
  • Hydroxycarbamide (can worsen anaemia)
  • Anagrelide, reduces platelet formation (can transform to MF)
  • alpha-IFN useful in <40yos.
24
Q

Investigation results in ET

A

Platelets >600*10^9
Blood film: large platelets, megakaryocyte fragments
BM: megakaryocytes + clustering

V617F mutation in 50%

25
Q

Myelofibrosis - what is it characterised by?

2 types?

A
Massive splenomegaly
Fibrosis of BM and increased megakaryocytes in BM
Older pts
Anaemic
Extramedullary haemopoiesis 

Primary: Genetic
Secondary: PV or ET, leukaemia etc

26
Q

Findings on blood film in MF

A

Tear drop cells (dacrocytes)
Leucoerythroblastic
Giant platelets
Circulating megakaryocytes

27
Q

Bone marrow in myelofibrosis - 3 things

A

Dry tap
Megakaryocyte clustering
Lots of fibrosis (Reticulin or collagen)

28
Q

Mx of myelofibrosis

A

Supportive: blood transfusions, splenectomy
Hydroxycarbamide (worsen anaemia)
Thalidomide
BMT only curative option

29
Q

Prognosis of MF and bad prognostic features

A

3-5 years

Severe anaemia <100g/L
Thrombocytopenia <100x10^9/
MASSIVE splenomegaly