myeloproliferative disorders Flashcards
(17 cards)
what is a myeloproliferative disorder?
- uncontrolled proliferation of a single type of stem cell
- considered a type of bone marrow cancer
what are the 3 main myeloproliferative disorders?
- Primary myelofibrosis- not associated with a specific cell line, but there is bone marrow fibrosis (haematopoetic stem cells)
- Polycythaemia vera- RBC proliferation
- Essential thrombocythaemia- platelet proliferation
what mutation is present in polycythemia vera and explain how it works?
JAK2 gene mutation
- normally erythropoietin released from the kidneys binds to JAK2 on RBC and stimulates them to divide
- however, if there is a mutation, JAK2 is always activated, and RBC divide even in the absence of erythropoietin
how does polycythemia vera progress?
- the excess abc die and cause fibrosis of the bone marrow
- the bone marrow can no longer produce blood cells and this is called the spent phase
- this leads to anaemia, thrombocytopenia and low WBC
this is basically 2dry myelofibrosis
what is the treatment for polycythemia vera?
Venesection can be used to keep the haemoglobin in the normal range. This is the first line treatment.
Aspirin can be used to reduce the risk of developing blood clots (thrombus formation).
Chemotherapy can be used to control the disease.
which mutations may be present in essential thrombocythemia?
- JAK2 gene mutation
- MPL receptor mutation
- calreticulin
these mutations make the signalling mutations that activate platelets become active all the time
can progress to myelofibrosis or leukaemia
what are the 3 main signs of someone with polycythemia vera?
- Conjunctival plethora (excessive redness to the conjunctiva in the eyes)
- A “ruddy” complexion
- Splenomegaly
what is a targeted therapy for the JAK2 mutation?
JAK 2 inhibitor (ruxolitinib)
why can you get hepatomegaly and splenomegaly with myelofibrosis
When the bone marrow is replaced with scar tissue the production of blood cells (haematopoiesis) starts to happen in other areas such as the liver and spleen.
This is known as extramedullary haematopoiesis and can lead to hepatomegaly and splenomegaly. This can lead to portal hypertension. If it occurs around the spine it can lead to spinal cord compression.
what are signs of underlying complications with myeloproliferative disorders
- Anaemia (except in polycythaemia)
- Splenomegaly (abdominal pain)
- Portal hypertension (ascites, varices and abdominal pain)
- Low platelets (bleeding and petechiae)
- Thrombosis is common in polycythaemia and thrombocythaemia
- Raised red blood cells (thrombosis and red face)
- Low white blood cells (infections)
what is the blood result finding for polycythemia vera?
Raised haemoglobin (more than 185g/l in men or 165g/l in women)
what is the blood result finding for primary thrombocythemia?
Raised platelet count (more than 600 x 109/l)
what is the blood result finding for myelofibrosis?- both primary and secondary
- Anaemia
- Leukocytosis or leukopenia (high or low white cell counts)
- Thrombocytosis or thrombocytopenia (high or low platelet counts)
A blood film in myelofibrosis can show teardrop-shaped RBCs, varying sizes of red blood cells (poikilocytosis) and immature red and white cells (blasts).
how can you diagnose myelofibrosis?
Bone marrow biopsy is the test of choice to establish a diagnosis. Bone marrow aspiration is usually “dry” as the bone marrow has turned to scar tissue.
what is the treatment of polycythemia vera?
Venesection can be used to keep the haemoglobin in the normal range. This is the first line treatment.
Aspirin can be used to reduce the risk of developing blood clots (thrombus formation).
Chemotherapy can be used to control the disease.
what is the treatment for essential thrombocythemia?
Aspirin can be used to reduce the risk of developing blood clots (thrombus formation).
Chemotherapy can be used to control the disease
what are the 3 main myeloproliferative disorders?
- primary myelofibrosis
- polycythemia Vera -a 9-
- Essential thrombocytopenia
