Polycythaemia Flashcards
what is the definition of PV?
Increase in number of red cells, could also involve high platelet counts
PV belongs to the group of Philadelphia chromosome-negative myeloproliferative neoplasms. It is a clonal haematopoietic disorder characterised clinically by erythrocytosis and often thrombocytosis, leukocytosis, and splenomegaly
what is the epidemiology of PV?
Increased with age
Slightly male dominated
Very rare in children
what is the aetiology of PV?
The precise aetiology of this disorder is unknown, although it is clear that affected haematopoietic stem cells (HSCs) acquire genetic mutations that lead to clonal haematopoiesis.
what are the risk factors for PV?
> 40yrs
Budd-Chiari syndrome (BCS)
Affected family member
what is the pathophysiology of PV?
JAK2 mutation
Mutations in bone marrow haematopoietic stem cells endow their progeny with a proliferative advantage. The JAK2 V617F mutation results in the activation of biochemical pathways involved in erythropoietin receptor signalling. In PV, this causes a trilineage expansion of morphologically normal red blood cells (RBC), white blood cells (WBC), and platelets. However, the JAK2 mutation burden does not directly correlate with the risk of thrombosis.
what are the key presentations of PV?
Presence of risk factors
Features of thrombosis
what are the signs of PV?
Presence of risk factors
Features of thrombosis
Features of haemorrhage
splenomegaly
what are the symptoms of PV?
Asymptomatic Headache Generalised weakness Fatigue Pruritus Night sweats Bone pain Erythromelalgia Facial redness
what are the first line and gold standard investigations for PV?
haemoglobin - high Haematocrit - WHO: >49% in men, >48% in women; British Committee for Standards in Haematology: >52% in men, >48% in women erythropoietin (ESR) - low WBC count - elevated Platelet count - elevated MCV - low LFTs - normal JAK2 gene mutation screen - mutation present 2
what are the differential diagnoses for PV?
Secondary polycythaemia
essential thrombocythemia
Chronic myelogenous leukemia
Polycythaemia due to elevated erythropoietin level
how is PV managed?
Aspirin 75mg daily Venesection on 2 occasions Hydroxycarbamide 500mg daily Aim to keep Haematocrit <0.45 Annual cardiovascular risk assessment
how is PV monitored?
Generally, long-term monitoring of this disorder requires the direction and supervision of an experienced haematologist. Blood counts are monitored on a regular basis to review control. Patients receiving cytoreductive therapy require blood count monitoring every 1 to 2 weeks at treatment initiation until stable, then every 3 to 6 months (or more frequently if clinically indicated)
what are the complications of PV?
Therapy-related leukemia Spent phase Acute leukaemia Hydroxycarbamide-associated Thrombosis
what is the prognosis of PV?
PV can exist as an indolent disorder and is frequently compatible with near-normal life for many years, but the risks of acute myeloid leukaemia, spent-phase PV (post-polycythaemia myelofibrosis), and severe thrombosis are ever present.
