Polycythaemia vera and essential thrombocythaemia in the elderly

Increased serum lactate dehydrogenase isoenzymes in Ph-negative chronic myeloproliferative diseases: a metabolic adaptation?

We evaluated the significance of lactate dehydrogenase (LDH) isoenzymes in chronic myeloproliferative disorders (CMDs) by studying LDH isoenzymes in the serum of patients with secondary polycythemia (SP), polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF) in different disease status. LDH activity and isoenzymes were evaluated retrospectively in serum samples from four groups of patients and compared with a control group. LDH activity and isoenzyme distributions of patients with SP and PV did not reveal significant variations with respect to controls. In the ET and IMF group LDH isoenzyme revealed significant variations: IMF showed significant increase of LDH2 and significant reduction of LDH5 isoenzyme, whereas ET showed significant decrease in LDH1 and increase of LDH3. These data suggest that LDH isoenzyme patterns may be a useful marker of CMDs, but this enzymatic pattern could be expression of a metabolic adaptation.

Polycythaemia vera and essential thrombocythaemia: current treatment strategies

Polycythaemia vera (PV) and essential thrombocythaemia (ET) are classified as Philadelphia-negative chronic myeloproliferative diseases. Both PV and ET are rare diseases, but the prevalence is high. Patients who have not been treated for the diseases are at great risk of morbidity and mortality as a result of thrombohaemorrhagic events. However, if patients have been well treated, their prognosis is good and life-expectancy approaches normal. This article provides diagnostic tools and flowcharts for treatment of PV and ET. Treatment of PV and ET should be risk-adjusted and individualised. Low-dose aspirin is recommended as an antiaggregative drug in both diseases. For PV, phlebotomy to control a haematocrit at <0.45 is the cornerstone in treatment, and treatment with hydroxycarbamide (hydroxyurea) or interferon (IFN)-alpha is added to reduce hypermetabolic symptoms or splenomegaly becoming cytoreductive. In ET, hydroxycarbamide and anagrelide are the most used drugs, and anagrelide may also be added in PV to reduce thrombocytosis. IFNalpha is the only myelosuppressive treatment available during pregnancy. Current controversies regarding treatment illustrate the need for more randomised clinical trials. Demonstration of over expression of the PV-1 gene and in particular the JAK-2 mutation will be novel diagnostic criteria and may have an impact for future therapy of both PV and ET.

Hydroxyurea therapy: a rare cause of reversible azoospermia

BACKGROUND

Essential thrombocythaemia (ET) is an uncommon chronic myeloproliferative disorder characterized by a marked increase in the number of platelets. Hydroxyurea is effective in preventing thrombosis in high-risk patients with essential thrombocythaemia. In previous studies different side effects of Hydroxyurea have been pointed out, but attention has not really been focused on the possible side effects on spermatogenesis.

CASE

A 35-year-old man under investigation for haematospermia and complaining of erythromyalgia was found to have a thrombocytosis with a platelet count of 1130 x 10(9)/l. Bone marrow aspiration confirmed a diagnosis of essential thrombocythaemia. He was commenced on hydroxyurea (2 g daily) in order to lower his platelet count and relieve the erythromyalgia. The patient represented to the urologists, 3 years later with infertility and a semen analysis done by his doctor had shown azoospermia. Monthly sperm counts after the withdrawal of hydroxyurea showed a gradual return of the spermatogenesis to normal over a period of around 6 months. The patient's wife had conceived within 4 months of him stopping hydroxyurea.

CONCLUSION

This case highlights a very rare but nonetheless important side effect of treatment with hydroxyurea. Hydroxyurea can cause reversible inhibition of spermatogenesis and result in primary infertility. We believe that all patients being commenced on such treatment should be warned of this possibility and that they should be given the necessary follow-up investigations.

The role of blood component removal in essential and reactive thrombocytosis

An elevated platelet count is now a common finding in both hospitalized and ambulatory patients with the advent of automated complete blood cell counters. Clinicians may be called upon to make a distinction between a reactive process and a primary hematologic disorder as the cause of a thrombocytosis and to determine whether treatment is indicated. Essential thrombocythemia and other myeloproliferative disorders may present with marked increases in the platelet counts and may be associated with thrombohemorrhagic complications. Reactive thrombocytosis can be caused by iron deficiency and a variety of inflammatory conditions, infections, malignancy, bleeding or hemolysis, splenectomy, and drugs. Acute therapy for all of these disorders has included blood component removal, specifically plateletpheresis. The role of plateletpheresis in current management of thrombocytosis is considered, based on current knowledge of pathophysiology and a review of the literature.