40 - Chronic Myeloid Proliferative disease Flashcards
Chronic myeloproliferative disorder definition
Clonal stem cell disorders of the bone marrow
Malignant
E.gs of CMPD
Polycythaemia vera
Essential thrombocytosis
Idiopathic myelofibrosis
Polycythaemia vera
Increased RBCs
±neutrophils
±platelets
Need to distinguish between 2° polycythaemias and relative polycythaemias
Essential thrombocythaemia
Increased platelets
Need to distinguish from reactive thrombocytosis
Myelofibrosis
Variable cytopenias with a large spleen
Need to distinguish from other causes of spinomegaly
Polycythaemia vera - age distribution
All ages
Peak at 50-70
Polycythaemia vera - symptoms
Insidious Itching (aquagenic - hot baths) Plethoric face Headache, muzziness, general malaise Tinnitus Peptic ulcer Gout Gangrene of the toes
Polycythaemia vera - signs
Plethora
Engorged retinal veins
Splenomegaly
Polycythaemia vera - diagnosis
Persistent increased Hb/hct >0.5
Distinguish: relative vs absolute polycythaemia
&
primary vs secondary polycythaemia
Primary polycythaemia =
Polycythaemia vera
2° polycythaemia causes
Central hypoxic processes inc. chronic lung diseases, R->L shunts heart disease, CO poisoning, smoker, high altitude
Renal disease
EPO production tumours
Drugs: androgen preparations, postrenal transplant erythrocytosis
Congenital: high O2-affinity Hb; EPO receptor mediated
Idiopathic
Polycythaemia vera - second line tests
If EPO elevated: CXR, ABG, USS abdomen
EPO normal or low: JAK2 mutation, bone marrow exam, EXON12 mutation
JAK
Janus kinases (tyrosine kinases)
Signalling pathway for cytokine receptors
Presence of JAK2 V617F mutation in peripheral blood DNA is diagnostic for myeloproliferative disorders
JAK test
Allele specific DNA-based PCR
Polycythaemia vera - treatment
Venesections aim HCT
Thrombocytosis - two types
Primary
Reactive - surgery, infection, inflammation, malignancy, Fe deficiency, hyposplenism, haemolysis, drug induced, rebound post chemo
Thrombocytosis - investigation
Persistent platelets >450 x109/l
1st line: FBC and film, ferratin, CRP, CXR, ESR
Thrombocytosis - 2nd line investigations
JAK2
CALR
Bone marrow biopsy
Extensive search for 2° cause
CALR mutation
Calreticulin mutation
Cell signalling protein produced in ER Mutation of Exon 9 Found in myeloid progenitors in ET Mechanism of action unknown Found in up to 90% of JAK2 negative ET
Thrombocytosis - diagnosis
JAK2 - 50%
CALR mutation - 45%
Thrombocytosis - treatment
Assess thrombotic risk - age, hypertension, diabetes, platelet count >1500, history of thrombosis
Antiplatelet treatment - aspirin 75mg daily, cytoreduction is high risk
How do you do cytoreduction?
Hydroxycarbamide
Inferferon
Anagrelide
P32
Thrombocytosis - prognosis
Excellent - 20 yr median survival
Risk of AML or myelofibrosis
CALD mutated have lower thrombosis risk
Myelofibrosis - presentation
Pancytopenia
B symptoms
Massive splenomegaly
Myelofibrosis - investigations
FBC and film
Haematinics
Myelofibrosis - diagnosis
Blood film
Bone marrow results
JAK2 mutation (50%)
CALR mutation (30%)
Splenomegaly - causes
CHICAGO
Cancer Haematological Infection Congestion Autoimmune Glycogen storage disorders Other - amyloid
Myelofibrosis - treatment
Supportive care
JAK2 inhibitors
Bone marrow transplant
Myelofibrosis - prognosis
Poor - median survival 5 years
Chronic myeloid leukaemia - prevalence
Rare 1 per 100,000
Median age is 55-60
M:F = 1.5:1
Chronic myeloid leukaemia - characteristics
Leucocytosis+++
Leucoerythroblastic blood picture
Anaemia
Splenomegaly
Chronic myeloid leukaemia - symptoms
Ab discomfort Ab pain Fatigue Venous occlusion Gout
Chronic myeloid leukaemia - treatment for chronic phase
Low dose oral cytotoxic drugs (busulphan, hydroxycarbamide, IFN)
Chronic myeloid leukaemia - treatment for acute crisis
Intensive chemo
Poor outcome
Chronic myeloid leukaemia - allogenic bone marrow transplant
Curative in 50% of patients
Chronic myeloid leukaemia - imatinib resistance
Activating loop mutations in BCR-ABL confer resistance and loss of disease control
New TKI e.g. nilotinib, dasatinib
Chronic myeloid leukaemia - imatinib use
Designer molecular therapy
Model and paradigm for other cancers
Tyrosine kinase inhibitors (TKIs) increasingly used in solid tumours
Chronic myeloid leukaemia - summary
Pluripotent stem cell disorder
Defined by the t(9;22) translocation
Driven by BCR-ABL fusion tyrosine kinase
Chronic phase followed by acute transformation
Designer molecule treatment (imatinib) has proved highly successful
BCR-ABL mutations confer resistance to imatinib