Haematology 4 - Chronic myeloproliferative neoplasms Flashcards
What is the target of imatinib?
Mutated tyrosine kinase (by BCR-ABL gene)
What is the normal role of janus kinases?
They activate the STAT pathway, which promotes cell growth and replication
How does JAK2 mutation cause uncontrollable replication?
No longer need growth factor to activate
In polycythaemia vera, what else will be abnormal on the FBC other than red cell count?
Pronounced thrombocytophilia and slight granulocytophilia
Recall some symptoms of polycythaemia vera
Due to hyperviscosity: - Headaches - visual disturbances - dyspnoea Due to increased histamine release: - peptic ulcer - aquagenic pruritis
Recall four clinical findings in polycythaemia vera
Plethora
Erythromelalgia (red, painful extremities)
Gout
Retinal vein engorgement
What is the expected level of erythropoietin in polycythaemia vera?
Low
What mutation is present in all patients with polycythaemia vera?
JAK2
How should pseudopolychthaemia and polycythaemia vera be differentiated?
Isotype dilution method
Recall 3 causes of increased EPO
Hypoxia
Uterine myoma
Renal cancer
Recall 3 causes of pseudopolycythaemia
Alcohol
Obesity
Diuretics
Recall 3 ways in which polycythaemia vera can be treated
- Venesection
- Cytoreductive therapy
- Aspirin to reduce thrombosis risk
What is idiopathic erythrocytosis?
An isolated erythrocytosis with low EPO, where JAK2 V617 mutation is absent (although JAK mutation in exon 12 may be present)
How should idiopathic erythrocytosis be treated?
Venesection only
How is essential thrombocytothaemia defined?
Chronic myeloproliferative neoplasm with a sustained thrombocytosis > 600 x 10^9/L
