Haematology - myeloproliferative disorders Flashcards
What happens in myeloproliferative disorders? What are three examples
Uncontrolled proliferation of a single type of stem cell. They are considered a type of bone marrow cancer.
Primary myelofibrosis
Polycythaemia vera
Essential thrombocythaemia
Difference in pathophysiology between primary myelofibrosis, polycythaemia vera, essential thrombocythaemia
Primary myelofibrosis is the result of proliferation of the hematopoietic stem cells.
Polycythaemia vera is the result of proliferation of the erythroid cell line.
Essential thrombocythaemia is the result of proliferation of the megakaryocytic cell line.
What may these myeloproliferative disorders progress to?
AML
What mutation is particularly associated with these disorders?
JAK2
What is myelofibrosis?
Fibrosis of the bone marrow due to cytokines released in proliferation of cell lines
Can occur in primary myelofibrosis, polycythaemia vera or essential thrombocythaemia
What is the consequence of myelofibrosis?
Haematopoesis (blood cell production) starts to occur in other areas e.g. liver and spleen (extramedullary haematopoiesis)
This can cause splenomegaly, hepatomegaly and portal hypertension
Presentation of myeloproliferative disorders
Systemic symptoms - fatigue, night sweats, weight loss, fever
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 are the three key signs seen in polycythaemia vera?
Conjunctival plethora - excessive redness to the conjunctiva in the eyes
Ruddy complexion
Splenomegaly
FBC findings in myeloproliferative disorders
PV - raised Hb
Primary thrombocythaemia - raised platelets
Myelofibrosis:
- E.g. due to primary MF or secondary to PV or ET can give variable findings
- Anaemia
- Leukocytosis or leukopenia
- Thrombocytosis or thrombocytopenia
What are the blood film findings in myelofibrosis?
Tear-drop shaped RBCs
Varying sizes of RBCs
Immature red and white cells (blasts)
What is poikilocytosis?
The term for abnormally shaped red blood cells in the blood.
Poikilocytes may be flat, elongated, teardrop-shaped, crescent-shaped, sickle-shaped, or may have pointy projections, or other abnormal features.
How is diagnosis of myeloproliferative disorders made?
FBC is essential
Bone marrow biopsy is the diagnostic test
Bone marrow aspiration is usually dry - bone marrow has turned to scar tissue
Could also test for JAK2, MPL and CALR genes, which can help guide management
Management of primary myelofibrosis
Mild disease/ minimal symptoms- may monitor and not actively treat
Allogeneic stem cell transplantation is potentially curative but carries risks.
Chemotherapy can help control the disease, improve symptoms and slow progression but is not curative on its own.
Supportive management of the anaemia, splenomegaly and portal hypertension.
Management of polycythaemia vera
Venesection is first line
Aspirin can help reduce risk of thrombus formation
Chemotherapy can be used to control the disease
Management of essential thrombocythaemia
Aspirin to reduce risk of thrombus formation
Chemotherapy can be used to control the disease
