prv
Table of Contents
polycythaemia rubra vera
introduction
- myeloproliferative disorder resulting in polycythaemia
- ~10 new cases per million population per year
- incidences of polycythaemia vera, essential thrombocythaemia, and myelofibrosis were 10x higher among Ashkenazi Jews in northern Israel than in persons of Arabic descent in the region.
- most cases occur in those 40-60 yrs old and are due to acquired (not inherited) mutations in genes such as JAK2, TET2
- rarely, risk of PRV may be inherited in an autosomal dominant manner
clinical features
- usually discovered on routine blood testing
- may cause:
- non-specific symptoms including headaches
- 40% develop pruritis after showers/baths
- high RBC may cause a ruddy complexion
- hypertension due to increased blood volume which may get to twice normal
- stroke (CVA) due to hyper-viscosity
- deep venous thrombosis (DVT), acute myocardial infarction (AMI/STEMI/NSTEMI), Budd-Chiari syndrome (BCS) due to hyper-viscosity
- bleeding / easy bruising / GIT bleeding
- 20% present with gout
- some develop erythromelalgia - this responds well to aspirin
- 10% transform into myelofibrosis
- 3% transform into acute myeloid leukaemia
lab tests
- FBE:
- raised haematocrit > 0.52 in men and > 0.48 in women
- raised RBC mass > 25% above normal
- neutrophis and basophils may be raised
- raised platelet count in 50% of patients
- low ESR due to increase in zeta potential
- JAK2 mutation is strongly associated
- those who are JAK2 negative may need bone marrow biopsy
treatment
- there is no current curative Rx, but most patients have an almost normal life span with life-long treatment
- low dose aspirin seems to halve the risk of thrombotic complications in those with no PH thrombotic events 1)
- asymptomatic patients aged < 40 years can be considered for therapeutic phlebotomies alone to maintain a hematocrit level of less than 45% although this Rx is being re-evaluated
- other patients can undergo myelosuppressive therapy with hydroxyurea 500 mg PO twice per day (titrated to effect)
- appears to reduce stroke risk by a further 30%
- these patients may eventually develop myelofibrosis
-
- Ruxolitinib (Jakafi) 10 mg PO twice per day appears to be superior to hydroxyurea for disease control HOWEVER:
- serious withdrawal symptoms make gradual dose reduction important
- 82% developed anaemia, 67% thrombocytopenia and 15% neutropenia hence need to monitor FBE
- radioactive phosphorous can be used as an alternative therapy in older patients
prv.txt · Last modified: 2023/01/09 04:45 by wh