Haematology 10: CML and myeloproliferative disorders Flashcards
What are MPNs?
Myeloproliferative neoplasms:
A myeloproliferative disorder that lead to an excess of differentiated myeloid cells (platelets, RBCs and leukocytes)
What are some examples of MPNs? mutation / what proportion?
Essential Thrombocythaemia - JAK2 (55%)
Polycythaemia Vera - JAK2 (95%)
Myelofibrosis - JAK2 (50%)
CML (classesd as an MPN)
What is essential thrombocythaemia? cause?
Megakaryocytes are making too many platelets leads to a v. high platelet count (>450 consistently)
JAK2 mutation in 55%
No evidence of other cause
What is the mx of essential thrombocythaemia?
Aspirin to reduce stroke risk
Hydroxycarbamide to lower count
What is polycythaemia (ruba) vera
Excess RBC production -> Haematocrit >0.52 / 0.48 (M / F), Often thrombocythaemia as well
Hyperviscosity, hypervolaemia, hypermetabolism -> Headaches, light-headedness, visual disturbance, fatigue, dyspnoea
High risk of thrombotic events e.g. MI, Stroke, Budd-Chiari (portal vein thrombosis)
95% association w/ JAK2
What is the mx of polycythaemia vera?
Aspirin to reduce stroke risk
Venesection (taking blood to lower haematocrit)
Hydroxycarbamide to lower count
How does myelofibrosis occur?
Clonal proliferation of stem cells in the bone marrow
This results in cytokine release and fibrosis of the bone marrow
As a result, there is reduced production of all cell lineages (this is different to the other ones as they have increased production)
NB: Polycythaemia vera and essential thrombocythaemia can both progress to this
What are the features of myelofibrosis?
JAK2 mutation present in 50%
Pancytopenia
Splenomegaly (can be massive splenomegaly) - as seen in Exam Qs
What else can classically present with massive splenomegaly in exam Qs?
CML
Myelofibrosis
Leishmanasis
Mx of myelofibrosis?
Stem cell transplant likely only cure - if early and before BM has fibrosed
Ruloxitnib - JAK inhibitor
What are the different types of polycythaemia vera?
Primary - familial / PV
Secondary - Disease, high altitude, chronic hypoxia
Pseudo - reduced plasma volume, dehydration
Difference between early and late myelofibrosis?
Prefibrotic -> mild changes, isolated thrombocytosis
Fibrotic -> splenomegaly, blood changes, dry tap (BUZZWORD), prominent collagen fibrosis in histological section, osteoscleoris
Typical presentation of CML?
- Typically onset age 35-55 in EMQs
- LUQ pain - Splenomegaly
- Mostly asymptomatic if diagnosed in chronic phase
May present with symptoms of acute leukaemia if in accelerated / blast phase (~10%) - not seen as much these days
CML blood test results?
WCC - V. high (can include all different stages - myelocytes to neutrophils)
Hb normal or low
Plt - high initially but can drop later in disease
Basophils - Raised (caused by few conditions)
Monocytes - Should be low (if its high indicates CMML)
Blood film of CML?
- “Left shift”
- Leukocytosis
- Eosinophilia
- Basophilia
Hypoloblated megakaryocytes