From the Guidelines
Polycythemia vera is the disease process that leads to an elevated platelet count on a CBC. This myeloproliferative disorder causes overproduction of all blood cell lines, including platelets (thrombocytosis), red blood cells (erythrocytosis), and white blood cells (leukocytosis) 1. The elevated platelet count occurs because of uncontrolled proliferation of megakaryocytes in the bone marrow due to mutations, most commonly in the JAK2 gene. In contrast, the other conditions typically cause decreased platelet counts. Sepsis and disseminated intravascular coagulation (DIC) lead to platelet consumption and thrombocytopenia as platelets are activated and used up in widespread clotting. Splenic sequestration causes thrombocytopenia because an enlarged spleen traps and stores platelets, removing them from circulation.
Key points to consider in the management of polycythemia vera include:
- Phlebotomy to maintain the hematocrit below 45% 1
- Daily low-dose acetyl salicylic acid to reduce the risk of thrombotic complications 1
- Cytoreduction in high-risk cases, such as patients with an age older than 60 years, or those with a previous thrombotic event 1
- Management of cardiovascular risk factors to reduce the risk of thrombosis 1
Polycythemia vera patients often have platelet counts exceeding 450,000/μL, sometimes reaching over 1 million/μL, which significantly increases their risk of both thrombotic and bleeding complications. The most recent guidelines recommend targeting hematocrit levels to <45% to lower the risk of thrombosis 1. Overall, polycythemia vera is the disease process that leads to an elevated platelet count on a CBC, and its management should focus on reducing the risk of thrombotic complications and improving quality of life.
From the Research
Disease Processes Leading to Elevated Platelet Count
The following disease processes can lead to an elevated platelet count on a CBC:
- Polycythemia Vera: characterized by erythrocytosis, often with associated leukocytosis and thrombocytosis 2, 3, 4, 5, 6
- Key features of Polycythemia Vera include:
- Erythrocytosis (hemoglobin >16.5 mg/dL in men or >16.0 mg/dL in women)
- Thrombocytosis (53%) and leukocytosis (49%)
- Presence of JAK2 gene variant (more than 95% of patients)
- Increased risk of thrombosis and progression into myelofibrosis or acute myeloid leukemia
- Other options, such as sepsis, disseminated intravascular coagulation, and splenic sequestration, are not directly associated with an elevated platelet count in the provided studies. However, it is essential to note that sepsis can lead to thrombocytosis in some cases, but this is not explicitly mentioned in the provided studies. Disseminated intravascular coagulation typically leads to thrombocytopenia, and splenic sequestration can lead to thrombocytopenia due to platelet pooling in the spleen.