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Myeloproliferative Disorders Notes

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This is an extract of our Myeloproliferative Disorders document, which we sell as part of our Haematology Notes collection written by the top tier of University Of Leicester students.

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Myeloproliferative Disorders A group of four disease caused by clonal proliferation of haemopoeitic stem cells
- Chronic myeloid leukaemia
- Myelofibrosis
- Polycythaemia ruba vera
- Essential throbocythaemia

Chronic myeloid leukemia Clonal proliferation of myeloid precursor cells (neutrophils, basophils, eosinophils) Chronic = abnormality further down the cell line therefore more differentiated cells
= More treatable Pathogenesis
- Presence of Philadelphia chromosome (9:22 translocation forming bcrabl gene) o Produces a protein that is thought to be oncogenic Clinical features
- 3 distinct clinical phases Primary = chronic phase - symptoms of anaemia, anorexia and weight loss May have marked splenomegaly. Neutropenia or thrombocytopenia not usually present Secondary = accelerated phase - insidious deterioration. Requires increased amount of treatment to control spleen size and WCC Tertiary = blast phase - usually fatal. Presents as an acute leukaemia Diagnosis
- Blood count o Raised WCC - usually >100/10x9 o Low Hb o Low platelets
- Film o Shows increasing numbers of morphologically normal myelocytes and neutrophils o Basophilia o Blast cells
- BM aspirate and trephine o Less useful o Cytogenetics show Philadelphia chromosome (in 95% of cases) Management
- Chronic phase o Chemo o Alpha interferon o Allogeneic stem cell transplant - only cure o Imatanib - tyrosine kinase inhibitors for Philadelphia chromosome BCR-abl gene) - targeted treatment
- Blast crisis o Management as for acute leukaemia

o

Can induce remission back into 'chronic phase' - temporarily

Prognosis
- Best predictor = initial response to treatment
- Can monitor with blood counts and cytogenetics (ph. Cr disappears therefore bcr-abl reduces)

Myelofibrosis Clonal proliferation of haemopoeitic stem cells, which release growth factors
- Particularly platelet-derived growth factor and cytokines Epidemiology
- Mean age of presentation = 60years Clinical features
- Anaemia
- Splenomegaly (often painful and massive)
- Systemic symptoms o Weight loss o Fever Investigations
- FBC o Anaemia o Raised WCC o Raised platelets
- Blood film o Immature red and white cells (leukoerythroblastic change) o Tear-drop RBC
- Bone marrow aspirate and trephine o BM often inaspirable due to fibrosis o Trephine biopsy is hypocellular with increased marrow fibrosis Management
- Supportive treatment o Blood transfusion, anabolic steroids and EPO for anaemia o Splenectomy useful in painful splenomegaly or to reduce transfusion requirements
- Hydroxyurea can be used to control high WCC and reduce spleen size o But has no impact on marrow fibrosis Prognosis
- Median survival 4 years
- Poor prognostic factors = increasing age, anaemia, leukopenia, abnormal marrow karyotype

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