Journal Mobile

R Kumar, S Prem
Journal Issue: 
Volume 37: Issue 1: 2007




Patients with raised haemoglobin or haematocrit need evaluation for the presence of polycythaemia. The term erythrocytosis should be used when only the red cells are affected, while polycythaemia is preferred for the clonal disorder  involving  all  three  haematopoietic  cell  lines, namely  PV.   Secondary erythrocytosis  is  far  more  common  and  is  usually  consequent  to  increased erythropoietin  production.   It  is  important  to  diagnose  PV, as  it  has  a  high morbidity and mortality. The diagnostic criteria for PV are complex.  Recently, an activating point mutation in the JAK2 gene (JAK2-V617F) has been detected in  a  majority  of  PV  patients, but  is  not  specific, and  needs  more  evaluation. Patients  may  present  with  plethora,  thrombosis  in  arterial  or  venous circulations,  erythromelalgia,  pruritus,  haemorrhage,  splenomegaly,  gout, leucocytosis, or thrombocytosis.

Management  consists  of  reducing  haematocrit  to  below  0·45, primarily  by venesection.  Low-dose  aspirin  should  be  administered  to  all  patients  unless contraindicated.  Cyto-reductive therapy is indicated only if venesection is not tolerated,  for  high-risk  illness,  extreme  thrombocytosis,  and progressive disease.  Hydroxycarbamide (previously known as hydroxyurea) is the simplest and  most  effective  medication, being  preferred  in  all  except  young  patients. Interferon  is  also  effective,  but  is  more  toxic  and  inconvenient  to  use. Anagrelide  may  be  used  to  control  platelet  counts, but  hydroxycarbamide appears  superior.   In  the  very  elderly, P  or  low-dose  busulfan  has  a  role because   of   the   convenience,   despite   a   greater   risk   of   leukaemic transformation.   With  appropriate  therapy,  survival  has  improved  from  an average of two years to more than ten years.  Special care is needed during pregnancy, prior to general surgery, and in the management of haemorrhage,
pruritis, and splenomegaly.