From the Guidelines
High platelets and erythrocytes should be evaluated by a hematologist as they may indicate a myeloproliferative disorder, with initial management including diagnostic testing and potential cytoreductive therapy to reduce the risk of thrombosis and bleeding complications. The management of these conditions is guided by the risk of thrombosis, with age older than 60 years and previous thrombosis being major predictors of vascular complications 1.
Diagnostic Testing
Diagnostic testing should include a complete blood count, peripheral blood smear, JAK2 mutation analysis, and erythropoietin levels to determine the underlying cause of the elevated platelets and erythrocytes.
Risk Stratification
Risk stratification is crucial in managing myeloproliferative disorders, with the International Prognostic Scoring System (IPSS) being used to stratify patients with primary myelofibrosis (PMF) 1.
Treatment
For symptomatic patients with elevated platelets, aspirin 81-100mg daily may be prescribed to reduce thrombotic risk. If polycythemia vera is diagnosed, therapeutic phlebotomy to maintain hematocrit below 45% is typically recommended, along with cytoreductive therapy such as hydroxyurea (starting at 500-1000mg daily) in high-risk patients 1. Essential thrombocythemia may be managed with hydroxyurea or anagrelide depending on risk factors, with cytoreductive treatment recommended for patients who shift to the high-risk category by reaching the age of 60 years or by the occurrence of a major thrombotic or hemorrhagic event 1.
Ongoing Monitoring
These conditions require ongoing monitoring as they can increase the risk of blood clots, bleeding complications, and cardiovascular events. Secondary causes like dehydration, hypoxia, or inflammatory conditions should also be ruled out before confirming a primary hematologic disorder. The elevated blood cell counts occur because of dysregulated bone marrow production, often due to genetic mutations affecting the JAK-STAT pathway that controls blood cell production.
From the Research
High Platelets and Erythrocytes
- High platelets and erythrocytes can be indicative of myeloproliferative neoplasms (MPN), a heterogeneous group of clonal blood disorders characterized by an overproduction of blood cells 2.
- The classic Philadelphia chromosome-negative MPN consist of myelofibrosis, polycythemia vera, and essential thrombocythemia 2.
- Thrombocytosis, or elevated platelet count, can be primary (essential thrombocythemia) or secondary (reactive thrombocytosis) 3.
- Essential thrombocythemia is a myeloproliferative neoplasm associated with mutations of genes that regulate thrombopoiesis, and can lead to thrombotic and hemorrhagic complications 3.
- Polycythemia vera is characterized by an overproduction of erythrocytes, and can also lead to thrombotic complications 4, 5.
Diagnostic Approach
- Diagnostic workup of patients with high platelets and erythrocytes requires integration of numerous diagnostic modalities, including careful morphologic evaluation of the peripheral blood smear, clinical findings, and other laboratory results 4.
- Bone marrow biopsy is essential for the diagnosis of MPN, as it provides information on bone marrow histology and morphology of megakaryocytes 6.
- Molecular techniques, such as JAK2 mutation analysis, can also be applied in bone marrow biopsies as supporting evidence of certain features of MPN 6.
Treatment and Management
- Treatment of MPN depends on the specific subtype and severity of the disease, and may include medications such as ruxolitinib and interferon-α2 5.
- Combination therapy with ruxolitinib and low-dose pegylated interferon-α2 has been shown to be effective in improving cell counts, reducing bone marrow cellularity and fibrosis, and decreasing JAK2 V617F burden in patients with polycythemia vera or myelofibrosis 5.