Polycythaemia vera

Polycythaemia vera (previously called polycythaemia rubra vera) is a myeloproliferative disorder caused by clonal proliferation of a marrow stem cell leading to an increase in red cell volume, often accompanied by overproduction of neutrophils and platelets. It has recently been established that a mutation in JAK2 is present in approximately 95% of patients with polycythaemia vera and this has resulted in significant changes to the diagnostic criteria. The incidence of polycythaemia vera peaks in the sixth decade.

Features

• pruritus, typically after a hot bath
• ‘Ruddy complexion’
• splenomegaly
• hypertension
• hyperviscosity
  • arterial thrombosis
  • venous thrombosis
• haemorrhage (secondary to abnormal platelet function)
• low ESR
• Hyperuricaemia & gout → painful swelling in the MTP joints
• Peptic ulcer disease

Following history and examination, the British Committee for Standards in Haematology (BCSH) recommend the following tests are performed

• full blood count/film (raised haematocrit; neutrophils, basophils, platelets raised in half of patients)
• JAK2 mutation
• serum ferritin
• renal and liver function tests

If the JAK2 mutation is negative and there is no obvious secondary causes the BCSH suggest the following tests:

• red cell mass