MYELOPROLIFERATIVE DISORDERS Flashcards
What are the classic myeloproliferative disorders?
Non cancer:
Polycythaemia vera
Essential thrombocythaemia
Cancer:
Idiopathic myelofibrosis
(CML)
What defines polycythaemia?
Raised PCV (packed cell volume)
What are the upper limits of packed cell volume in men and women?
- 51 in men
0. 48 in women
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)
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
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
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
What would the full blood count of someone with polycythaemia vera show?
Raised WCC
Raised platelet
Raised PCV
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
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
How often is venesection performed in someone with polycythaemia vera?
Quite frequently at first but eventually every 6-10 weeks
What is the prognosis for someone diagnosed with polycythaemia vera?
Usually good
20% incidence of transformation to myelofibrosis and 5% to acute leukaemia
How is apparent polycythaemia treated?
Venesection only done in patients with increased risk of vascular complications for other reasons.
What is the central diagnosis feature of essential thrombocythaemia?
A persisting platelet count of more than 600x10^9/L
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