Clinical and laboratory assessment of a patient with thrombocytosis.

Elevated platelet counts are frequently encountered in hospital medicine and arise from both physiological and pathological mechanisms. Thrombocytosis may be secondary, reflecting an inflammatory state, iron deficiency, recent surgery or point towards an underlying neoplasm. Thrombocytosis may be the presenting sign of solid tumours and haematological conditions. The discovery of the activating mutations affecting thrombopoiesis led to greater understanding of the pathobiology of essential thrombocythaemia and other myeloproliferative neoplasms. The investigation of suspected primary thrombocytosis has evolved to include testing for these disease-associated mutations. Therapy for patients with essential thrombocythaemia aims to reduce their risk of thrombotic complications by addressing cardiovascular risk factors, and using antiplatelet agents and, in selected patients, cytoreductive therapy. This article provides a logical approach to distinguishing reactive or secondary thrombocytosis from thrombocytosis associated with an underlying myeloproliferative neoplasm and gives an overview of the management of essential thrombocythaemia.

How to interpret and pursue an abnormal complete blood cell count in adults.

A complete blood cell count (CBC) is one of the most common laboratory tests in medicine. For example, at our institution alone, approximately 1800 CBCs are ordered every day, and 10% to 20% of results are reported as abnormal. Therefore, it is in every clinician's interest to have some understanding of the specific test basics as well as a structured action plan when confronted with abnormal CBC results. In this article, we provide practical diagnostic algorithms that address frequently encountered conditions associated with CBC abnormalities including anemia, thrombocytopenia, leukopenia, polycythemia, thrombocytosis, and leukocytosis. The objective is to help the nonhematologist recognize when a subspecialty consultation is reasonable and when it may be circumvented, thus allowing a cost-effective and intellectually rewarding practice.

Anagrelide: an update on its mechanisms of action and therapeutic potential.

Thrombocytosis is an increasingly recognized clinical problem due to the widespread availability of automated cell counters. While reactive thrombocytosis does not require any therapeutic intervention, clonal thrombocytosis may require therapy to prevent thrombohemorrhagic complications. The clinician has a number of therapeutic options available when confronted with a patient having clonal thrombocytosis. One of these agents is anagrelide (Agrylin, Bristol-Myers Squibb). In this drug profile, a synopsis of the available data on this agent and its role in the control of thrombocytosis will be provided. The main side effects of the medication are discussed, as well as the potential future developments in the field.