Vnitr Lek 2005, 51(7-8):861-872

Thrombocytosis and thrombocythemia

J. Schwarz^1,*, M. Penka²

¹ Klinický úsek Ústavu hematologie a krevní transfuze, Praha, přednosta doc. MUDr. Petr Cetkovský, Ph.D.

² Oddělení klinické hematologie FN Brno, pracoviště Bohunice, přednosta prof. MUDr. Miroslav Penka, CSc.

In this review, we recommend the nosological classification of the Ph- myeloproliferative disorders with thrombocythemia (MPD-T) to be performed either according to the WHO or to the Rotterdam criteria, both of which are based on demonstration of specific histopathological features of the respective MPD-T. The most frequent of the primary MPD-Ts is the proliferative, prefibrotic or early fibrotic phase of idiopathic myelofibrosis, but reactive thrombocytoses are even more frequently seen. The differences between the primary MPD-Ts and secondary thrombocytoses are discussed along with the issue of clonality of these disorders and the methodology of its determination. The most serious complications of MPD-Ts are the following: 1. arterial and venous thromboses, 2. transformation of MPD-T into secondary acute myeloid leukemia, 3. microcirculation problems, 4. hemorrhage. The main risk factors of thrombosis are age, history of previous thrombosis, thrombocyte counts 350-2 200 × 10⁹/L and the presence of an additional thrombophilic risk factor (hereditary thrombophilia, malignancy, gravidity, hypercoagulable states, cardiovascular disease). Treatment of MPD-T, according to the recommendations of the Czech multiinstitutional group, should be stratified with respect to the thrombotic and hemorrhagic risks. In high-risk patients, thromboreductive treatment is warranted. Seeing to the possible leukemogenicity of all the cytostatic drugs used, including hydroxyurea, they should not be administered over prolonged periods of time to individuals less than 60 years old. In these patients, interferon-α or anagrelide should be preferred. In low-risk patients, antiaggregation therapy is sufficient.

Keywords: myeloproliferative disease; thrombocythemia; secondary thrombocytosis; risk factors; diagnostics; clonality; leukemic transformation; thrombosis; treatment algorithm; hydroxyurea; interferon; anagrelide

Received: March 11, 2005; Accepted: March 11, 2005; Published: July 1, 2005  Show citation