From the Guidelines
Elevated platelets, or thrombocytosis, is most commonly associated with primary bone marrow disorders, such as essential thrombocythemia (ET) or polycythemia vera (PV), as well as secondary causes like infections, inflammation, or iron deficiency anemia. The etiology of elevated platelets can be multifactorial, including genetic mutations leading to autonomous platelet production in primary thrombocytosis, or reactively to underlying conditions in secondary thrombocytosis 1.
Common Causes of Thrombocytosis
- Primary thrombocytosis: essential thrombocythemia, polycythemia vera, chronic myeloid leukemia, or myelofibrosis
- Secondary thrombocytosis: infections, inflammation, iron deficiency anemia, malignancies, post-splenectomy states, and tissue damage
- Medication-induced thrombocytosis: epinephrine, vincristine, and all-trans retinoic acid
Evaluation and Management
The evaluation of thrombocytosis should include a complete blood count, peripheral blood smear, iron studies, inflammatory markers, and possibly bone marrow examination if primary thrombocytosis is suspected. Management focuses on treating the underlying cause for secondary cases, while primary thrombocytosis may require cytoreductive therapy like hydroxyurea or anagrelide, along with low-dose aspirin to prevent thrombotic complications, as suggested by studies on myeloproliferative neoplasms 1.
Risk Stratification
Advanced age and history of thrombosis are the most consistent risk factors associated with the risk of thrombosis, as identified in a cohort of patients with PV 1. The potential benefit of initiation of cytoreductive therapy based on elevated blood counts, including thrombocytosis, at diagnosis has not been evaluated in prospective studies, but it is essential to consider the risk of major hemorrhage and thrombosis in patients with elevated platelet counts.
From the FDA Drug Label
3 Aspirin and Drugs that Increase Bleeding Risk Co-administration of single-dose or repeat-dose anagrelide and aspirin showed greater ex vivoanti-platelet aggregation effects than administration of aspirin alone Results from an observational study in patients with essential thrombocythemia suggest the rate of major hemorrhagic events (MHEs) in patients treated with anagrelide is higher than in those subjects treated with another cytoreductive treatment The majority of the major hemorrhagic events occurred in patients who were also receiving concomitant anti-aggregatory treatment (primarily, aspirin).
The etiology of elevated platelets is essential thrombocythemia.
- Essential thrombocythemia is a condition characterized by an overproduction of platelets in the bone marrow.
- Anagrelide is used to treat this condition by reducing platelet production.
- The use of anagrelide in patients with essential thrombocythemia may increase the risk of major hemorrhagic events, particularly when used in combination with other medications that increase bleeding risk, such as aspirin 2.
From the Research
Elevated Platelets Etiology
Elevated platelets, also known as thrombocytosis, can be caused by various factors. In the context of essential thrombocythemia, the etiology is often related to genetic mutations that upregulate the JAK-STAT signaling pathway.
- The most common genetic variants associated with essential thrombocythemia are:
- Other factors that may contribute to elevated platelets in essential thrombocythemia include:
- The diagnosis of essential thrombocythemia is based on a combination of clinical, laboratory, and molecular criteria, including a persistent platelet count of 450 × 10^9/L or greater, and the exclusion of other myeloid neoplasms 3, 5