Haem Malignancy: Myloproliferative Disorders And Myelodysplastic Disorders Flashcards
What are myeloproliferative disorders?
Caused by clonal proliferation of haematopoietic myeloid stem cells in the bone marrow.
These cells can differentiate into RBCS, WBCS, or platelets, causing an excess of one or more of these cell types
What types of myeloproliferative disorders do you get?
- Primary myelofibrosis
- Polycythaemia vera
- Essential thrombocythaemia
Dr Tom says above are 3 main
Myeloproliferative disorders have the potential to progress and transform into ……?
What gene mutations are myeloproliferative disroders associated with?
- Can progress and transform into acute myeloid leukaemia
Gene mutations:
* JAK2
* MPL
* CALR
TOM TIP: Remember the JAK2 mutation for your exams. This can be the target of JAK2 inhibitors such as ruxolitinib.
What is polycythaemia vera?
what is it caused by?
- myeloproliferative disorder characterised by the excess production of erythrocytes.
- 98% of cases caused by a genetic mutation in the JAK2 gene
Myeloproliferative disorders result in the excess production of myeloid cells: erythrocytes (red blood cells), platelets or granulocytes (neutrophils, eosinophils and basophils).
When excess red blood cells are produced resulting in a raised haemoglobin concentration and haematocrit this is called…?
polycythaemia
Contrast primary and secondary polycythaemia
primary polycythaemia
* polycythameia vera - excess erythroyctes due to JAK 2 gene
Secondary polycythaemia
* physiological response to chronic hypoxia (i.e. smoking / chronic lung disease), renal e.g. renal artery stenoiss , or excess EPO (i.e. EPO secreting tumours)
RF for polycythemia vera ?
- Advancing age: median age at diagnosis is 60-70 years
- History of Budd-Chiari syndrome: a proportion of people will have a JAK2 mutation even if they had initially normal blood counts
RF for polycythemia vera ?
- Advancing age: median age at diagnosis is 60-70 years
- History of Budd-Chiari syndrome: a proportion of people will have a JAK2 mutation even if they had initially normal blood counts
History of symptoms fro Polycythaemia vera?
- Headaches: usually associated with dizziness and sweating
- Myalgia and weakness
- Fatigue
- Tinnitus
- Pruritis: particularly after a hot shower or bath
- Erythromelalgia: burning pain, warmth and redness in the hands and feet
- Blurred vision: temporary loss of vision due to hyper-viscosity
- Dyspepsia: peptic ulceration
- Gout: due to increased cell turnover
- thrombosis (75% arterial) i.e presnt with STROKE, MI, DVT, PE, BUDD CHIARI sydnrome
What might you see when clinically examinaing a pt with polycythaemia vera?
- a ‘ruddy’ (reddish) / plethoric complexion
- Splenomegaly
- Abdominal masses: benign and malignant uterine, renal and hepatic tumours which can secrete EPO may be palpable
- Hypertension
Differencial diagnosis for polycythaemia vera? i.e. raised HB
Hypoxia driven:
* COPD
* smoking
* carbon monoxide poisoning
* sleep apnoea
* left to right cardiac shunts (Eisenmenger’s syndrome)
* high altitude
Local renal hypoxia:
* e.g.renal artery stenosis
Pathological EPO production:
* EPO secreting tumours; e.g. clear cell renal carcinoma, Wilms’ tumour, hepatocellular carcinoma, cerebellar haemangioblastoma, pheochromocytoma, uterine myoma, parathyroid carcinoma and meningioma
Investigations for polycythaemia vera: how is it defined in terms of lab resutls
dont think really need to know off by heart
Polycythaemia is defined as:
- Haemoglobin (Hb) >185 g/L and/or haematocrit (Hct) > 0.52 in males
- Hb >165 g/L and/or Hct > 0.48 in females
- Red cell mass >25% above predicted
If a pt is dehydrated they may have apparent polycythaemia. The hb and haematocrit is riased.
why is it raised?
What can you look at to work if true polycythaemia?
What other lab results may be raised?
- Hb / Hct is raised due to reduced plasma volume (dehydrated)
- look at - red cell mass - will be normal
- Neutrophilia and thrombocytosis often see in PV
What are other lab investigations for Polycythaemia vera? think about ruling stuff in / out
FBC:
* high: RCC, Hb, HCt, PCV, WBC, platelets
Blood film:
* assess for leukaemia - require BM assessment
U&E/LFTs:
* renal/hepatic causes ( tumours), complications (e.g. Budd-Chiari syndrome)?
Serum ferritin:
* normal or low - big demand for iron
Arterial blood gas:
* hypoxia? (smoking) raised carboxyhaemoglobin?
Serum EPO:
* suppressed levels - PV.
* raised levels -secondary cause; inappropriate EPO production and the possibility of an EPO-secreting tumour.
JAK 2 V617F mutational analysis:
* positive in 95% of patients with PV
Specialist investigations and imaging for poylcythaemia vera?
Bone marrow biopsy:
* to distinguish from secondary PV
* hypercellularity, erythroid hyperplasia
Imaging:
* Abdominal US - splenomegaly and exlcude secondary causes of PV i.e. renal and hepatic
* CT head/neck/chest/abdo/pelvis - rare EPO secreting tumours