Myeloproliferative disorders - Polycythaemia vera Flashcards
What can cause increased erythropoiesis?
Physiological reaction
Myeloproliferative disorders
What are myeloproliferative disorders known as?
Myeloproliferative neoplasms
What are the different types of myeloproliferative neoplasms?
Essential thrombocytosis
Polycythaemia vera
Myelofibrosis
What are the genetic defects in myeloproliferative neoplasms? What are the consequences?
Point mutation in Janus kinase 2 gene
Produces tyrosine kinase
that gives increased proliferation and survival of haematopoietic precursors
How do the genetic defects of myeloproliferative neoplasms affect treatment?
Give drugs targetting the abnormal protein
How is haematopoiesis affected in myeloproliferative neoplasms?
Overproduction of a certain cell, or few cells
cells are abnormal
How is the bone marrow affected in myeloproliferative neoplasms?
Hypercellular bone marrow
Marrow fibrosis
How are organs affected in myeloproliferative neoplasms?
Extramedullary haematopoisis in liver, spleen
What can myeloproliferative neoplasms develop into?
Acute leukaemia
How is polycythaemia vera diagnosed?
High haematocrit
or
Raised red cell mass
Is polycythaemia vera more common in younger or older people?
Older people
Is polycythaemia vera more common in males or females?
Neither!
equally common in both
What is erythrocytosis?
Increase in conc. of red blood cells
What are the types of erythrocytosis?
Relative
Absolute
What is relative erythrocytosis?
Normal red cell mass, but decrease in plasma volume gives increase in red blood cell conc.
What is absolute erythrocytosis?
Increase in red cell mass gives increase in conc. of red blood cells
What are the types of absolute erythrocytosis?
Primary
Secondary
What is primary absolute erythrocytosis?
Polycythaemia vera
What is secondary absolute erythrocytosis?
Increased erythropoietin production gives increased red blood cell mass
What are the types of causes of increased erythropoietin production?
Physiological
Pathological
What are some examples of physiological causes of increased erythropoietin production?
Hypoxia
- right to left shunts
- chronic lung disease
- renal artery stenosis
- high altitude
What are some examples of pathological causes of increased erythropoietin production?
Cancers
What are the signs and symptoms of polycythaemia vera?
Arterial thrombosis
Venous thrombosis
Splenomegaly
Haemorrhage into skin, GI tract
Gout
Pruritis
What can polycythaemia vera develop into?
Acute leukaemia
How is polycythaemia vera managed?
Venesection to reduce haematocrit
Aspirin to reduce risk of blood clotting
Maybe use drugs to reduce overproduction of red blood cells
When are drugs used to treat polycythaemia?
Poor tolerance to venesection
Worsening symptoms e.g. progressive splenomegaly
