Myeloproliferative disorders Flashcards
What could cause relative polycythemia? (HINT: this is to do with low plasma rather than increased RBCs)
ACUTE:
Dehydration
Alcohol
Diuretics
CHRONIC form:
Obesity, HTN and a high alcohol and tobacco intake.
What are causes of absolute polycythemia?
Primary: polycythemia rubra vera
Secondary:
Hypoxia (e.g. hight altitude, chronic lung disease, heavy smoking, cyanotic congenital heart disease)
OR
inappropriately increased EPO secretion (e.g. renal carcinoma, hepatocellular carcinoma)
What mutation is seen in >90% of patients with polycythemia rubra vera?
JAK2
What is the pathology of polycythemia rubra vera?
Malignant proliferation of a clone derived from one pluripotent marrow stem cell.
The erythroid progenitor offspring do not need EPO to avoid apoptosis.
Excess proliferation of RBCs, WBCSs and platelets is seen, leading to hyperviscosity and thrombosis.
What cells proliferate in essential thrombocythaemia?
Megakaryocytes (leading to increased platelets with abnormal function)
What is the treatment for essential thrombocythaemia?
Low-dose Aspirin 75mg daily.
Hydroxycarbamide given to patients >60 or if previous thrombosis.
What is the pathology of myelofibrosis?
Hyperplasia of megakaryocytes, which produce platelet-derived growth factor, leading to intense marrow fibrosis and myeloid metaplasia (haemopoiesis in the liver and spleen) and thus massive hepatosplenomegaly.
What is the treatment of myelofibrosis?
Marrow support.
Allogenic stem cell transplantation may be curative in young people but has high risk of mortality.
Prognosis= 4-5yrs median survival.
What is the treatment for polycythemia rubra vera?
Aim to keep haematocrit
What are the main complications of polycythemia rubra vera?
Thrombosis
Haemorrhage (due to defective platelets)
Transition to myelofibrosis (30%), acute leukaemia (5%),
