Idiopathic erythrocytosis

Also known as 'benign erythrocytois' (although it does not always have a benign course) and 'pure erythrocytois' (since it was thought to be a pure red cell disorder), this condition applies to patients with increased red cell mass but investigations do not reveal any form of known primary or secondary erythrocytosis (1).

According to several studies there is a male preponderance to this disease (1).

The incidence of vascular complications is high in idiopathic erythrocytosis:

• 46.6% patients at presentation in one study and 17% of the total patients died of cerebrovascular accidents
• according to another study the incidence of fatal thromboembolic and haemorrhagic events was similar to patients with polycythemia vera (1)

Management plan of idiopathic erythrocytosis include:

• venesection
  • to reduce the Hct to < 0.45 if Hct is > 0.54
  • to reduce the Hct to < 0.45 if < 0.54 and there is increased risk of thrombosis i.e evidence of ischaemia, previous history of thrombosis, peripheral vascular disease, diabetes or hypertension
• cytoreductive therapy is contraindicated (1)

Reference:

• 1. McMullin MF et al. Amendment to the guideline for diagnosis and investigation of polycythaemia/erythrocytosis. Br J Haematol. 2007;138(6):821-2