Other Haematological Disorders Flashcards
What is myelodysplastic syndrome?
Myelodysplastic syndrome is caused by the myeloid pluripotent stem cells not maturing properly and therefore not producing healthy blood cells. There are a number of specific types of myelodysplastic syndrome.
The stem cell clone gives rise to intermediate cell types that are defective and are particularly susceptible to apoptosis, resulting in death within the bone marrow before they reach maturity. This, in turn, causes insufficiency in the numbers of mature blood cells, which may affect one or several cell lines - red blood cells (RBCs), white blood cells (WBCs) and/or platelets. Importantly, 30% of patients with MDS eventually progress to AML.
What’s the difference between MDS and AML?
The only difference between myelodysplastic syndrome and acute myeloid leukemia, is that in myelodysplastic syndromes the cells can mature into something, while in acute myeloid leukemia they can’t mature at all. If in myelodysplastic syndromes, maturation stops occurring, the disease becomes the same thing as acute myeloid leukemia.
Who is myelodysplastic syndrome more common in?
- Older pts (>60yrs)
- Previous chemotherapy or radiotherapy
What 3 blood abnormalities can myelodysplastic syndrome lead to?
Low levels of cells that originate from myeloid cell line:
- Anaemia
- Neutropenia
- Thrombocytopenia
How does myelodysplastic syndrome present?
- May be asymptomatic and diagnosed on FBC for something else
- Symptoms of anaemia (SOB, fatigue, pallor)
- Symptoms of neutropenia (frequent or severe infections)
- Thrombocytopenia (bruising, bleeding, purpura)
How is myelodysplastic syndrome diagnosed? Highlight the confirmatory test
- FBC: anaemia, leucopenia, thrombocytopenia
- Blood film: blast cells
- Bone marrow biopsy= confirmatory test: blast cells
Discuss the management of myelodysplastic syndrome
Depending on the symptoms, risk of progression and overall prognosis the treatment options are:
- Watchful waiting
- Supportive treatment with blood transfusions if severely anaemic
- Chemotherapy
- Stem cell transplantation
What may myelodysplastic syndrome progress to?
AML
What are myeloproliferative disorders?
State the 3 myeloproliferative disorders
Chronic conditions in which there is abnormal clonal proliferation of one or more cells lines of myeloid lineage. Considered a type of bone marrow cancer.
Three myeloproliferative disorders:
- Primary myelofibrosis
- Polycythaemia vera
- Essential thrombocythaemia
Proliferation of what cells occurs in polycythaemia vera?
Proliferation of erythroid cells
(Medicine in a minute says can also affect myeloid & megakaryocyte cell lines but mostly affects erythroid)
What mutation is present in ~90% of polycythaemia vera patients?
JAK2 mutation
*JAK2 is a tyrosine kinase protein responsible for cell signalling in bone marrow haematopoietic stem cells. Mutations up-regulate sensitivity towards growth factors such as erythropoietin & thrombopoietin)
State signs & symptoms of polycythaemia vera
May be asymptomatic; pesentation often insidious:
- Hyperviscosity syndrome:
- End-organ congestion: visual disturbance, neurological symptoms (headache, dizziness, tinnitus), cardiac (angina, SOB)
- Blood stasis: thrombosis, bleeding (high shear force through capillaries)
- Splenomegaly
- Pruritis
- Erythromelalgia (burning & erythema in hands & feet. <5%)
- Plethoric appearance (conjunctival plethora & ruddy complexion)
- Hypertension (⅓)
- Systemic symptoms (fatigue, weight loss, night sweats, fever)
What initial investigations should you do in suspected polycythaemia vera?
- FBC: raised haematocrit, ~50% may also have raised neutrophils/basophils/platelets
- U&Es: renal func
- LFTs: liver damage
- Coagulation: liver func
- JAK2 mutation screen
*Bone marrow biopsy usually unnecessary if have raised haematocrit and are JAK2 positive
Threshold for haematocrit when diagnosing polycythaemia vera changes depend on whether JAK2 positive or negative. What is the threshold for men and for women in JAK2 positive patients?
Male: >0.52
Female: >0.48
Discuss the management of polycythaemia vera
- First line to keep Hb in range= venesection
- Aspirin (reduce risk of thrombus formation)
- Chemotherapy (hydroxycarbamide)
State some potential complications of polycythaemia vera
- Thrombotic events (significant cause mortality)
- Progression to myelofibrosis
- Progression to AML