What Is Thrombocythemia?
Elevated platelet counts may be caused by a cytokine-driven (reactive) mechanism, or by clonal / tumorous megakaryocyte overgrowth that is independent of growth factors (spontaneous), resulting in thrombocytosis, such as myeloproliferative tumors or chronic myeloid leukemia Wait. Reactive thrombocytosis refers to thrombocytosis due to medical or surgical conditions in the absence of chronic myeloproliferative diseases. When these conditions are resolved, the platelet count returns to normal. Spontaneous thrombocytosis refers to patients diagnosed with chronic myeloproliferative tumors including true erythrocytosis, primary myelofibrosis, chronic myelogenous leukemia, myelodysplastic syndrome refractory anemia, and increased annular iron granulocytes. Have thrombocytosis. Primary thrombocytosis is a clonal disease of hematopoietic stem cells based on megakaryocyte proliferation.
Basic Information
- Visiting department
- Department of Hematology
- Common causes
- Thrombocytosis caused by various reasons.
- Common symptoms
- Symptoms such as headache and fatigue caused by blood clots.
- Contagious
- no
Causes of Thrombocytosis
- 1. Reactive thrombocytosis is seen in infections, after surgery, malignant tumors, after splenectomy, acute blood loss or iron deficiency, trauma, non-infectious inflammation, etc. These causes lead to platelet growth factors (such as thrombopoietin, interleukins) -6) Increased release leads to thrombocytosis.
2. Spontaneous thrombocytosis is found in myeloproliferative diseases, such as true erythrocytosis, early myelofibrosis, and chronic myelogenous leukemia.
3. The pathogenesis of primary thrombocytosis may be related to changes in thrombopoietin and thrombopoietin receptors and activation of downstream pathways. 50% of patients with primary thrombocytosis have mutations in the JAK2V617F gene, 3% to 5% of patients have mutations in the MPL gene, and 15% to 25% of patients have mutations in the CALR gene.
Clinical manifestations of thrombocytosis
- Patients with reactive thrombocytosis and spontaneous thrombocytosis have primary symptoms. Patients with primary thrombocythemia are insidious onset, have nonspecific symptoms such as fatigue, fatigue, and occasionally diagnosed due to routine blood tests or splenomegaly. Patients have an increased incidence of thrombosis, including symptoms associated with arterial and venous thrombosis. There are also patients with headache, visual symptoms, and erythema limb pain due to microvascular thrombosis. A small number of patients have bleeding symptoms, including gastrointestinal bleeding, nosebleeds, bleeding gums, and hematuria. 50% to 80% of patients have splenomegaly, mostly moderate, and giant spleen is rare.
Thrombocytosis test
- Primary thrombocytosis Blood platelet count 450 × 109 / L, mostly at (600 3000) × 109 / L. Platelets can be seen as agglomerates, and occasionally large, deformed or small platelets. Leukocytes can increase (10 ~ 30) × 109 / L. The classification is mainly based on neutrophils.
2. Bone marrow picture cytology showed that nucleated cell proliferation was active or significantly active, especially megakaryocyte proliferation, which was characterized by an increase in large mature megakaryocytes and a large number of platelet aggregation.
3 Platelet and coagulation function were measured in abnormal platelet function. In the aggregation test, platelet response to collagen, ADP, and arachidonic acid-induced aggregation decreased. The bleeding time can be prolonged, the prothrombin consumption time is shortened, and the blood clot is poorly retracted.
4 Genetic mutation testing can detect JAK2V617F gene mutations in 50% of patients, 3% to 5% of patients have MPL gene mutations, and 15% to 25% of patients have CALR gene mutations.
Thrombocytosis diagnosis
- Peripheral blood platelets exceeding 450 × 109 / L are called thrombocytosis.
Primary Thrombocytosis Diagnostic Standards [2016 World Health Organization (WHO) Standards]: Meets 4 major criteria or the first 3 major and minor criteria.
1. Continuous platelet count 450 × 109 / L;
2. Bone marrow examination is mainly megakaryotic hyperplasia, and the number of mature multi-lobed large megakaryocytes is mainly increased. There is no obvious granulocytic hyperplasia or left shift or erythroid hyperplasia and rare small increase in reticular fibers;
3. Chronic myelogenous leukemia, polycythemia vera, primary myelofibrosis, myelodysplastic syndrome or other myeloid tumors that do not meet WHO diagnostic criteria;
4. Accompanied by JAK2 V617F gene mutation or MPL, CALR gene mutation.
There was evidence of clonal markers or unresponsive thrombocytosis in the secondary criteria.
Thrombocytosis treatment
- 1. Reactive thrombocytosis actively treats the primary disease. After the primary disease is controlled, the platelet count gradually returns to normal.
2. Primary thrombocythemia currently lacks a specific treatment for the disease. The purpose of treatment is to reduce the number of platelets, prognosis of thrombosis and bleeding, and reduce disease progression. Treatment regimens are graded according to the risk of thrombotic complications in ET patients.
(1) Screening for hypertension, hyperlipidemia, diabetes, and smoking history, and appropriate treatment.
(2) Unless there is contraindication, all patients with ET are treated with aspirin.
(3) Patients in the high-thrombotic group were treated with cytoreductive drugs, including hydroxyurea, anagrelide, and interferon.
Thrombocytosis prognosis
- Most patients with ET progress slowly, and their median survival is often more than 10-15 years. About 10% of patients progress to bone marrow fibrosis, and leukemia is rare (2%).