Materiały źródłowe

• #1 Thrombocytosis: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/13350-thrombocytosis

  Thrombocytosis involves having an elevated level of platelets in your blood. There are two main types of thrombocytosis: essential thrombocythemia and reactive thrombocytosis. In severe cases, thrombocytosis can cause dangerous clots in your blood vessels, increasing your risk of a stroke or heart attack. Your experience of thrombocytosis, including its seriousness and whether you need treatment, depends on its cause. […] Thrombocytosis (pronounced throm-boe-sie-TOE-sis) is having too many platelets in your blood. Too many platelets, however, can cause your blood to become too sticky. […] Essential thrombocythemia (ET), or primary thrombocytosis, is a rare blood disorder in which your bone marrow makes too many platelets. With essential thrombocythemia, blood cell production goes wrong, causing you to have abnormal and excess platelets.

• #2 Thrombocytosis: Diagnostic Evaluation, Thrombotic Risk Stratification, and Risk-Based Management Strategies

  https://pmc.ncbi.nlm.nih.gov/articles/PMC3200282/

  Thrombocytosis is a commonly encountered clinical scenario, with a large proportion of cases discovered incidentally. The differential diagnosis for thrombocytosis is broad and the diagnostic process can be challenging. Thrombocytosis can be spurious, attributed to a reactive process or due to clonal disorder. This distinction is important as it carries implications for evaluation, prognosis, and treatment. Clonal thrombocytosis associated with the myeloproliferative neoplasms, especially essential thrombocythemia and polycythemia vera, carries a unique prognostic profile, with a markedly increased risk of thrombosis. This risk is the driving factor behind treatment strategies in these disorders. […] The threshold for clinically significant thrombocytosis is variable from patient to patient, and the exact definition of thrombocytosis also varies in the literature, although a platelet count of 450 109/L is a generally accepted value.

• #3 Thrombocytosis: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/13350-thrombocytosis

  Reactive, or secondary, thrombocytosis happens when your platelets increase in response to something else a condition, an injury, an infection, surgery, absent spleen, etc. With reactive thrombocytosis, you have high platelets because your body reacts to an underlying cause. […] As thrombocytosis doesnt typically cause symptoms, the first sign is often a high platelet count that shows up during routine blood work (complete blood count). Thrombocytosis involves having more than 450,000 platelets per microliter of blood. If you have elevated levels, your healthcare provider will likely order a follow-up blood test a few weeks later to see if your levels remain high. […] Identifying the underlying condition (such as iron deficiency anemia, cancer or infection) thats raising your levels helps healthcare providers diagnose and manage reactive thrombocytosis. If your provider cant find a secondary cause, theyll run tests to see if you have essential thrombocythemia.

• #4 Approach to the patient with thrombocytosis – UpToDate

  https://www.uptodate.com/contents/approach-to-the-patient-with-thrombocytosis

  Approach to the patient with thrombocytosis […] Thrombocytosis refers to an increased platelet count which, in this review, is ≥450,000/microL (≥450 x 10^9/L). […] This topic discusses our approach to the adult or child with unexplained thrombocytosis. […] Clinical manifestations and diagnosis of specific causes of thrombocytosis are discussed separately. […] The following terminology and values are used in this topic: Platelets – Platelets are cellular fragments that are derived from megakaryocytes in the bone marrow.

• #5 Essential Thrombocytosis Workup: Approach Considerations, Histologic Findings, Blood Studies

  https://emedicine.medscape.com/article/206697-workup

  The principal diagnostic criteria for essential thrombocytosis (primary thrombocythemia) are an elevated platelet count, bone marrow megakaryocytic proliferation, and presence of JAK2, CALR, or MPL mutation. […] Accordingly, the tests and procedures used in the workup for essential thrombocytosis include the following: Complete blood cell count (CBC), Genetic studies For JAK2 V617F, CALR, and MPL mutations, Bone marrow aspirate and biopsy, Coagulation studies, Platelet aggregation studies, Serum chemistry, Iron studies (to rule out reactive thrombocytosis secondary to iron deficiency). […] A complete blood cell count (CBC) is essential for the diagnosis of essential thrombocytosis. CBC findings are as follows: The hallmark of essential thrombocytosis is a sustained, unexplained elevation in the platelet count.

• #6 Thrombocytosis – Augusta HealthSearchClose SearchSearch IconSearch IconClose Search IconMobile Menu IconMobile Menu Close IconInstagramFacebookTwitterYoutube

  https://www.augustahealth.com/disease/thrombocytosis/

  Your doctor might detect thrombocytosis in a routine blood test result that shows a high platelet level. If your blood test indicates thrombocytosis, it’s important to determine whether it’s reactive thrombocytosis or essential thrombocythemia to know how to manage the condition. […] During an exam for a routine physical or another condition, your doctor might find that your spleen is enlarged or you have signs or symptoms of an infection or another condition. In that case, your doctor might order a complete blood count. This test can determine whether your platelet count is higher than normal. […] Because a number of conditions can cause a temporary rise in your platelet count, your doctor likely will repeat the blood test to see if your platelet count remains high over time. […] Your doctor might also order tests to check for: Abnormal levels of iron in your blood, Markers of inflammation, Undiagnosed cancer, Associated gene mutations. […] You might also need a procedure that uses a needle to remove a small sample of your bone marrow for testing.

• #7 Essential Thrombocytosis Workup: Approach Considerations, Histologic Findings, Blood Studies

  https://emedicine.medscape.com/article/206697-workup

  The principal diagnostic criteria for essential thrombocytosis (primary thrombocythemia) are an elevated platelet count, bone marrow megakaryocytic proliferation, and presence of JAK2, CALR, or MPL mutation. […] Accordingly, the tests and procedures used in the workup for essential thrombocytosis include the following: Complete blood cell count (CBC), Genetic studies For JAK2 V617F, CALR, and MPL mutations, Bone marrow aspirate and biopsy, Coagulation studies, Platelet aggregation studies, Serum chemistry, Iron studies (to rule out reactive thrombocytosis secondary to iron deficiency). […] A complete blood cell count (CBC) is essential for the diagnosis of essential thrombocytosis. CBC findings are as follows: The hallmark of essential thrombocytosis is a sustained, unexplained elevation in the platelet count.

• #8 Platelet Disorders – Thrombocythemia and Thrombocytosis | NHLBI, NIH

  https://www.nhlbi.nih.gov/health/thrombocythemia-thrombocytosis

  Thrombocythemia and thrombocytosis are conditions that occur when your blood has a higher-than-normal platelet count. […] To diagnose thrombocythemia or thrombocytosis, your provider will ask about your medical and family history. They will ask about your symptoms and do a physical exam to look for signs of blood clots or bleeding. […] Your provider may also order one or more of the tests below. […] A complete blood count (CBC) measures the levels of red blood cells, white blood cells, and platelets in your blood. […] A blood smear is used to look at your platelets and other blood cells. […] Bone marrow tests check whether your bone marrow is healthy. […] Genetic testing checks for mutations, or changes, in genes that control how your body makes platelets. […] Treatment for secondary thrombocytosis depends on its cause. People who have thrombocytosis usually do not need platelet-lowering medicines or procedures.

• #9 High Platelet Count | Learn About What This Means | LLS

  https://www.lls.org/myeloproliferative-neoplasms/essential-thrombocythemia/diagnosis

  While certain signs and symptoms may indicate that a person has ET, a series of tests are needed to confirm the diagnosis. […] It is important to have an accurate diagnosis, as it helps the doctor to: […] Evaluation of an individual with suspected ET should start with a detailed medical history and a physical examination by a hematologist-oncologist. […] After the medical history, the doctor will conduct a physical examination. […] This test measures the number red blood cells, white blood cells and platelets in a sample of blood. […] In patients with ET, the platelet count is higher than normal. […] A pathologist examines a small amount of blood under a microscope to see if there are any unusual changes in the size, shape, or appearance of the blood cells. […] In patients with ET, the platelets may appear enlarged and/or clumped together.

• #10 Essential Thrombocythemia Diagnosis & Treatment – NYC | Herbert Irving Comprehensive Cancer Center (HICCC) – New York

  https://www.cancer.columbia.edu/cancer-types-care/types/rare-blood-disorders/conditions/essential-thrombocythemia

  In this condition, the body produces too many platelets, cells that circulate in the blood and keep us from bleeding. This may result in abnormal clotting. […] A physician may order the following tests to confirm a diagnosis of ET: […] Complete blood count (CBC) to determine the number of platelets in the blood. […] Blood smear. A blood sample is examined under a microscope to check the number and shape of the platelets. […] Genetic testing for the JAK2 gene mutation. In ET, the calreticulin (CALR) and MPL genes can also be mutated. […] Other blood tests to check the level of iron in the blood or look for inflammation. These tests help to rule out other causes of elevated platelet count. […] Bone marrow aspiration. The physician uses a needle to remove a small amount of liquid bone marrow then examines it under a microscope for abnormal cells. […] Bone marrow biopsy. The physician uses a needle to take a sample of solid bone marrow tissue then examines it under a microscope. Patients with ET have an elevated number of the large cells that make up platelets (megakaryocytes) in their bone marrow.

• #11 Essential Thrombocythemia – Hematology and Oncology – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/hematology-and-oncology/myeloproliferative-disorders/essential-thrombocythemia

  The diagnosis is suggested by normal hematocrit, white blood cell count, mean corpuscular volume (MCV), and iron studies, as well as absence of the BCR-ABL translocation. […] Genetic studies should be done, including a quantitative JAK2 V617F assay (by next-generation sequencing [NGS] or quantitative polymerase chain reaction), along with a BCR-ABL assay to exclude chronic myeloid leukemia (CML, which can manifest with thrombocytosis alone). […] Patients who do not have JAK2 V617F, CALR, or MPL gene mutations (called triple negative) are rare. […] Mutation analysis should always be quantitative because the driver gene allele burden in JAK2 V617F-positive essential thrombocythemia does not exceed 50%. […] World Health Organization guidelines suggest that a bone marrow biopsy showing increased numbers of enlarged, mature megakaryocytes is required for a diagnosis of essential thrombocythemia, but this criterion has never been validated prospectively, and a marrow examination will not distinguish essential thrombocythemia from polycythemia vera.

• #12 Essential Thrombocytosis Workup: Approach Considerations, Histologic Findings, Blood Studies

  https://emedicine.medscape.com/article/206697-workup

  The principal mutations found in patients with essential thrombocytosis are in the JAK2 and CALR genes. […] The JAK2 V617F mutation is present in 50% of patients with essential thrombocytosis. […] Mutations in the calreticulin (CALR) gene have been reported in 15-25% of patients with essential thrombocytosis. […] A bone marrow aspirate and biopsy are useful. This uses specialized needles to obtain the aspirate and biopsy material from the posterior iliac crest. Obtaining an aspirate from the sternum is not recommended. […] Bone marrow findings in essential thrombocytosis are as follows: Approximately 90% of patients show an increase in bone marrow cellularity. Megakaryocytic hyperplasia is common. Giant megakaryocytes are often observed; clusters of megakaryocytes may be present; significant dysplasia of the megakaryocytes is unusual.

• #13 How I Work up the Patient with Thrombocytosis – The ASCO Post

  https://ascopost.com/issues/march-15-2012/how-i-work-up-the-patient-with-thrombocytosis/

  Thrombocytosis is defined as a platelet count greater than 400 109/L. […] In managing the patient with thrombocytosis, one must first distinguish reactive from primary thrombocytosis. […] The presence of chronic thrombocytosis, thrombohemorrhagic complications, microvascular symptoms, or splenomegaly favors the diagnosis of primary thrombocytosis. […] However, clinical impression often requires confirmation through laboratory testing, which is also necessary to distinguish among the different causes of primary thrombocytosis (including essential thrombocythemia). […] JAK2V617F mutation screening is now part of the diagnostic workup for thrombocytosis, according to the World Health Organization (WHO) diagnostic criteria for essential thrombocythemia and polycythemia vera. […] Bone marrow morphology appears normal in reactive thrombocytosis. In clonal thrombocythemia, bone marrow findings include increased numbers of megakaryocytes and other myeloid cells, abnormality in cell morphology, presence of megakaryocyte clusters, and reticulin fibrosis.

• #14 Essential thrombocythemia diagnosis – Cancer Therapy Advisor

  https://www.cancertherapyadvisor.com/home/decision-support-in-medicine/hospital-medicine/essential-thrombocythemia-3/

  Essential Thrombocythemia is also known as Essential Thrombocytosis or ET. ET is considered one of the myeloproliferative disorders and is characterized by persistently elevated platelet counts, usually 600. […] World Health Organization Diagnostic Criteria: Platelets 450K (was 600K in original Polycythemia Vera Study Group criteria). Proliferation of mature megakaryocytes on bone marrow. Must exclude: iron deficiency, polycythemia vera, chronic myelogenous leukemia, myelofibrosis, splenectomy, and reactive causes such as inflammation, malignancy. Revised criteria: JAK2 clonal marker present (or if not present, the above reactive causes excluded). JAK 2 is present in about 50% of cases of ET. […] What diagnostic tests should be performed? CBC with differential. Iron studies (iron, ferritin, TIBC). BCR-ABL gene rearrangement to evaluate for CML. JAK2. C-reactive protein, ESR. Bone marrow biopsy (optional, helpful if other studies unclear).

• #15 Essential Thrombocythemia Diagnosis & Treatment – NYC | Herbert Irving Comprehensive Cancer Center (HICCC) – New York

  https://www.cancer.columbia.edu/cancer-types-care/types/rare-blood-disorders/conditions/essential-thrombocythemia

  In this condition, the body produces too many platelets, cells that circulate in the blood and keep us from bleeding. This may result in abnormal clotting. […] A physician may order the following tests to confirm a diagnosis of ET: […] Complete blood count (CBC) to determine the number of platelets in the blood. […] Blood smear. A blood sample is examined under a microscope to check the number and shape of the platelets. […] Genetic testing for the JAK2 gene mutation. In ET, the calreticulin (CALR) and MPL genes can also be mutated. […] Other blood tests to check the level of iron in the blood or look for inflammation. These tests help to rule out other causes of elevated platelet count. […] Bone marrow aspiration. The physician uses a needle to remove a small amount of liquid bone marrow then examines it under a microscope for abnormal cells. […] Bone marrow biopsy. The physician uses a needle to take a sample of solid bone marrow tissue then examines it under a microscope. Patients with ET have an elevated number of the large cells that make up platelets (megakaryocytes) in their bone marrow.

• #16 Essential thrombocythemia diagnosis – Cancer Therapy Advisor

  https://www.cancertherapyadvisor.com/home/decision-support-in-medicine/hospital-medicine/essential-thrombocythemia-3/

  Essential Thrombocythemia is also known as Essential Thrombocytosis or ET. ET is considered one of the myeloproliferative disorders and is characterized by persistently elevated platelet counts, usually 600. […] World Health Organization Diagnostic Criteria: Platelets 450K (was 600K in original Polycythemia Vera Study Group criteria). Proliferation of mature megakaryocytes on bone marrow. Must exclude: iron deficiency, polycythemia vera, chronic myelogenous leukemia, myelofibrosis, splenectomy, and reactive causes such as inflammation, malignancy. Revised criteria: JAK2 clonal marker present (or if not present, the above reactive causes excluded). JAK 2 is present in about 50% of cases of ET. […] What diagnostic tests should be performed? CBC with differential. Iron studies (iron, ferritin, TIBC). BCR-ABL gene rearrangement to evaluate for CML. JAK2. C-reactive protein, ESR. Bone marrow biopsy (optional, helpful if other studies unclear).

• #17 Essential thrombocythemia diagnosis – Cancer Therapy Advisor

  https://www.cancertherapyadvisor.com/home/decision-support-in-medicine/hospital-medicine/essential-thrombocythemia-3/

  What laboratory studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted? Iron studies to exclude iron deficiency. BCR-ABL to exclude chronic myelogenous leukemia. CRP, ESR to exclude reactive causes. JAK2 mutation: positive in about 50% of patients, but not specific for ET and may be present in other myeloproliferative disorders. […] Over-utilized or wasted diagnostic tests associated with this diagnosis. Serum thrombopoeitin (TPO) levels: not specific for ET versus reactive causes. […] If ET is suspected, get JAK2 mutation which helps exclude reactive causes if it is positive. […] If ET is diagnosed during pregnancy or in a woman who may become pregnant, AVOID Hydroxyurea, as it may cause birth defects. […] Most patients have a normal life span. Adverse predictors of survival are age 60 years WBC 15 x 109/L.

• #18 Essential Thrombocythemia – Hematology and Oncology – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/hematology-and-oncology/myeloproliferative-disorders/essential-thrombocythemia

  The diagnosis is suggested by normal hematocrit, white blood cell count, mean corpuscular volume (MCV), and iron studies, as well as absence of the BCR-ABL translocation. […] Genetic studies should be done, including a quantitative JAK2 V617F assay (by next-generation sequencing [NGS] or quantitative polymerase chain reaction), along with a BCR-ABL assay to exclude chronic myeloid leukemia (CML, which can manifest with thrombocytosis alone). […] Patients who do not have JAK2 V617F, CALR, or MPL gene mutations (called triple negative) are rare. […] Mutation analysis should always be quantitative because the driver gene allele burden in JAK2 V617F-positive essential thrombocythemia does not exceed 50%. […] World Health Organization guidelines suggest that a bone marrow biopsy showing increased numbers of enlarged, mature megakaryocytes is required for a diagnosis of essential thrombocythemia, but this criterion has never been validated prospectively, and a marrow examination will not distinguish essential thrombocythemia from polycythemia vera.

• #19 Essential Thrombocytosis Workup: Approach Considerations, Histologic Findings, Blood Studies

  https://emedicine.medscape.com/article/206697-workup

  The principal mutations found in patients with essential thrombocytosis are in the JAK2 and CALR genes. […] The JAK2 V617F mutation is present in 50% of patients with essential thrombocytosis. […] Mutations in the calreticulin (CALR) gene have been reported in 15-25% of patients with essential thrombocytosis. […] A bone marrow aspirate and biopsy are useful. This uses specialized needles to obtain the aspirate and biopsy material from the posterior iliac crest. Obtaining an aspirate from the sternum is not recommended. […] Bone marrow findings in essential thrombocytosis are as follows: Approximately 90% of patients show an increase in bone marrow cellularity. Megakaryocytic hyperplasia is common. Giant megakaryocytes are often observed; clusters of megakaryocytes may be present; significant dysplasia of the megakaryocytes is unusual.

• #20 How I Work up the Patient with Thrombocytosis – The ASCO Post

  https://ascopost.com/issues/march-15-2012/how-i-work-up-the-patient-with-thrombocytosis/

  Essential thrombocythemia is currently defined as a persistent thrombocythemic state (platelet count 450 109/L) that is neither reactive nor associated with an otherwise defined myeloid malignancy. […] Therefore, before making a working diagnosis of essential thrombocythemia, in the context of primary thrombocytosis, one must exclude CML not only by conventional cytogenetics but also by a fluorescence in situ hybridization (FISH) test for BCR/ABL1. […] The second step in evaluating a patient with thrombocytosis is to confirm the diagnosis of essential thrombocythemia with a bone marrow examination and exclude the possibility of other myeloid disorders, including prefibrotic primary myelofibrosis.

• #21 Essential Thrombocythemia – Hematology and Oncology – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/hematology-and-oncology/myeloproliferative-disorders/essential-thrombocythemia

  The diagnosis is suggested by normal hematocrit, white blood cell count, mean corpuscular volume (MCV), and iron studies, as well as absence of the BCR-ABL translocation. […] Genetic studies should be done, including a quantitative JAK2 V617F assay (by next-generation sequencing [NGS] or quantitative polymerase chain reaction), along with a BCR-ABL assay to exclude chronic myeloid leukemia (CML, which can manifest with thrombocytosis alone). […] Patients who do not have JAK2 V617F, CALR, or MPL gene mutations (called triple negative) are rare. […] Mutation analysis should always be quantitative because the driver gene allele burden in JAK2 V617F-positive essential thrombocythemia does not exceed 50%. […] World Health Organization guidelines suggest that a bone marrow biopsy showing increased numbers of enlarged, mature megakaryocytes is required for a diagnosis of essential thrombocythemia, but this criterion has never been validated prospectively, and a marrow examination will not distinguish essential thrombocythemia from polycythemia vera.

• #22 Diagnostic Pathway for the Investigation of Thrombocytosis

  https://b-s-h.org.uk/guidelines/guidelines/diagnostic-pathway-for-the-investigation-of-thrombocytosis

  Chronic myeloid leukaemia (CML) may present with an isolated thrombocytosis and thus mimic essential thrombocythaemia (ET). The diagnostic criteria for ET proposed within the British Committee for Standards in Haematology guidelines (Harrison et al, 2010) are listed in Table 1. […] Here, A3 requires exclusion of CML, usually by demonstrating the absence of a BCR-ABL1 fusion gene or transcript in samples from bone marrow or peripheral blood. […] We would therefore like to clarify that we recommend testing for the presence of aBCR-ABL1 fusion in all patients lacking JAK2 V617F or MPL mutations, as well as in patients with any atypical features in order to ensure that category A3 is fulfilled.

• #23 Essential thrombocytosis: diagnosis, differential diagnosis, complications and treatment considerations of relevance for a cardiologist | mijn-bsl

  https://mijn.bsl.nl/essential-thrombocytosis-diagnosis-differential-diagnosis-compli/24011868

  In clinical practice 8090% of subjects with a platelet count above 450109/l do not have an essential/primary thrombocytosis, but have secondary/reactive thrombocytosis, which is an abnormally high platelet count secondary to underlying events, disease or medication. […] In the case of secondary thrombocytosis, the platelet count is rarely 1000109/l. […] Another, in fact erroneous, cause of thrombocytosis may result from the use of automated analysers. […] Hence, a peripheral blood smear might also differentiate primary/essential from artefactual/spurious thrombocytosis. […] Overall rates of complications in various regions/settings and using different definitions of events during long-term follow-up in patients with ET are relatively high. […] The incidence of thrombotic complications ranges from 9% to 84% at diagnosis and from 7% to 32% during long-term follow-up.

• #24 Reactive Thrombocytosis: Everything You Should Know

  https://www.healthline.com/health/reactive-thrombocytosis

  Reactive thrombocytosis is an unusually high platelet count. Also known as secondary thrombocytosis, it results from an underlying health condition, an injury, or a medication. […] When high platelet counts are due to an injury, a health condition, or a medication, your doctor may diagnose reactive thrombocytosis. You may only discover that you have reactive thrombocytosis when your doctor does blood work. […] If they discover that you have a high platelet count, they may recommend additional testing to rule out any serious underlying causes. […] Doctors typically divide thrombocytosis into two categories: reactive thrombocytosis and primary thrombocytosis. For proper treatment, its important for your doctor to determine which you have. […] Reactive thrombocytosis, which is also known as secondary thrombocytosis, is an unusually high platelet count due to an underlying health condition, an injury, or the use of a medication. […] An estimated 80-90% of people with thrombocytosis have reactive thrombocytosis. […] If your doctor determines that your platelet count is high, they may recommend additional testing to rule out health conditions like cancer.

• #25 Diagnosis and Treatment of Thrombocythemia in Myeloproliferative Disorders

  https://www.cancernetwork.com/view/diagnosis-and-treatment-thrombocythemia-myeloproliferative-disorders

  Myeloproliferative disorders originate in the clonal expansion of a transformed pluripotential hematopoietic progenitor cell. This results in a group of syndromes that include polycythemia vera, essential thrombocythemia, chronic myelocytic leukemia, and agnogenic myeloid metaplasia. […] Diagnostic criteria for polycythemia vera and essential thrombocythemia were codified by the Polycythemia Vera Study Group in 1967 and 1977. […] The defining characteristic of essential thrombocythemia is a sustained elevation of the platelet count above 600,000/mL in an untreated patient. […] Essential thrombocythemia is a diagnosis of exclusion, requiring the requisite platelet count, laboratory evidence excluding other myeloproliferative disorders, and a clinical evaluation finding no cause for reactive thrombocytosis.

• #26 Essential Thrombocythemia: Symptom, Treatment, Survival

  https://www.verywellhealth.com/essential-thrombocythemia-2860907

  Essential thrombocythemia (ET) is a rare form of blood cancer that causes the bone marrow to produce too many platelets (the blood cells responsible for clotting). […] The diagnosis is largely based on the exclusion of all other possible causes. […] The diagnosis of ET is largely exclusionary, meaning that any other cause for the high platelet count must be first excluded to make a definitive diagnosis.

• #27 Essential Thrombocytosis (ET) Diagnosis

  https://www.labce.com/spg766405_essential_thrombocytosis_et_diagnosis.aspx?srsltid=AfmBOoqd5L9MZ05qJa3OLep7PH7ofMG7MOTZIW4wc0wUcvAJkHvWWewQ

  The World Health Organization (WHO) has established these criteria for the diagnosis of ET. These criteria help to differentiate ET from other myeloproliferative disorders: Sustained platelet count of at least 450 x 109/L. Bone marrow biopsy showing predominant proliferation of enlarged mature megakaryocytes; no significant increase of granulocytic or erythroid precursors. This finding distinguishes essential thrombocythemia from another entity with thrombocytosis, namely prefibrotic primary myelofibrosis, which is identified by increased granulocytic or erythroid precursors, atypical megakaryocytes, and increased bone marrow cellularity. Not meeting criteria for polycythemia vera (p. vera), primary myelofibrosis, chronic myelogenous leukemia, myelodysplastic syndrome, or other myeloid neoplasm. Demonstration of JAK2(V617F) mutation or myeloproliferative leukemia (MPL) exon 10 mutation. In the absence of a clonal marker, there must be no evidence for reactive thrombocytosis. In particular, with a decreased serum ferritin, there must be no increase in hemoglobin level to p. vera range with iron replacement therapy. In the presence of a JAK2(V617F) or MPL mutation and exclusion of other myeloproliferative or myelodysplastic features, a bone marrow aspirate/biopsy may not be mandatory for a diagnosis. About 60% of patients with essential thrombocythemia carry a JAK2(V617F) mutation, and about 5% to 10% of the patients have activating mutations in the thrombopoietin receptor gene, MPL. About 70% of the patients without JAK2(V617F) or MPL carry a somatic mutation of the calreticulin gene, which is associated with a more indolent clinical course than is seen with JAK2(V617F) or MPL mutations.

• #28 High Platelet Count | Learn About What This Means | LLS

  https://www.lls.org/myeloproliferative-neoplasms/essential-thrombocythemia/diagnosis

  Although a bone marrow examination isn’t strictly necessary to make a diagnosis, doctors often use it to help confirm a ET diagnosis. […] If you have ET, your marrow will show a significant increase in platelet-forming cells (megakaryocytes). […] In suspected cases of ET, doctors test for mutations of the JAK2, MPL and CALR genes. […] Approximately 90 percent of patients with ET have a mutation of the JAK2, MPL or CALR gene. […] In 2016, the World Health Organization published new criteria for diagnosing ET. […] Diagnosis requires 4 major criteria OR major criteria 1-3 + minor criterion. […] Platelet count equal or greater than 450 x 109/L. […] Bone marrow biopsy showing increased numbers of platelet-forming cells (megakaryocytes) with abnormal nuclei. […] Presence of JAK2, CALR, or MPL mutation.

• #29 Essential Thrombocytosis Differential Diagnoses

  https://emedicine.medscape.com/article/206697-differential

  Elevation in the platelet count can result from physiologic or pathologic mechanisms. Essential thrombocytosis must be differentiated from secondary thrombocytosis, which may be due to an inflammatory state, iron deficiency, or recent surgery or to an underlying solid tumor or hematologic neoplasm. […] World Health Organization (WHO) guidelines propose four major criteria and one minor criterion for diagnosis of essential thrombocytosis. […] Diagnosis requires the presence of all 4 major criteria or the first 3 major criteria plus the minor criterion.

• #30

  https://haematologica.org/article/view/haematol.2022.280917

  Chronic thrombocytosis may be reactive in nature, be driven by inherited genetic characteristics (e.g., THPO, MPL, JAK2 mutations) or be caused by an acquired myeloid malignancy (mainly myeloproliferative neoplasm [MPN]). The diagnostic workup of isolated thrombocytosis therefore requires testing for inflammation/iron deficiency, consideration of a family history, a bone marrow examination and the search for „classical” MPN driver mutations (BCR-ABL1, JAK2V617F, CALRexon 9,MPLW515L/K). […] In a cohort of 130 patients with chronic, non-reactive triple-negative thrombocytosis, we first had bone marrow biopsies reviewed by experts of the French group of hematopathologists (GEBOM), then asked whether targeted NGS could help reach a diagnosis. We also asked whether the outcome of patients was predicted better when the diagnostic classification was based on genetic and/or histological features.

• #31

  https://haematologica.org/article/view/haematol.2022.280917

  Among the 130 patients with triple-negative thrombocytosis, bone marrow biopsy led to a diagnosis of ET/MPN in 79, while in 45 patients, the biopsy was not in favor of MPN and in six the diagnosis was unclear (insufficient quality). […] Since a histological diagnosis between MPN and non-MPN may be subject to variability and some patients still had unclear diagnosis, we wondered whether a mutational analysis with targeted NGS of 24 genes commonly mutated in MPN could help with the diagnostic discrimination of patients. […] Overall, pathogenic/likely pathogenic variants were found slightly more frequently in patients considered as having MPN after bone marrow biopsy review (33 variants in 17/69 (25%) vs. 10 variants in 8/50 (16%) in non-MPN patients, P=not significant). […] In order to assess whether NGS data could better discriminate thrombocytosis patients with a higher risk of complications, we reclassified patients with an acquired pathogenic or likely pathogenic variant in the MPN group, irrespective of their histology.

• #32 Essential thrombocytosis: diagnosis, differential diagnosis, complications and treatment considerations of relevance for a cardiologist | mijn-bsl

  https://mijn.bsl.nl/essential-thrombocytosis-diagnosis-differential-diagnosis-compli/24011868

  In clinical practice 8090% of subjects with a platelet count above 450109/l do not have an essential/primary thrombocytosis, but have secondary/reactive thrombocytosis, which is an abnormally high platelet count secondary to underlying events, disease or medication. […] In the case of secondary thrombocytosis, the platelet count is rarely 1000109/l. […] Another, in fact erroneous, cause of thrombocytosis may result from the use of automated analysers. […] Hence, a peripheral blood smear might also differentiate primary/essential from artefactual/spurious thrombocytosis. […] Overall rates of complications in various regions/settings and using different definitions of events during long-term follow-up in patients with ET are relatively high. […] The incidence of thrombotic complications ranges from 9% to 84% at diagnosis and from 7% to 32% during long-term follow-up.

• #33

  https://link.springer.com/article/10.1007/s12471-023-01757-4

  The incidence of thrombotic complications ranges from 9% to 84% at diagnosis and from 7% to 32% during long-term follow-up. […] For haemorrhage these rates range from 4% to 63% at diagnosis and from 8% to 14% during follow-up. […] These numbers clearly indicate that thrombotic complications surpass haemorrhagic complications, that both types of events often coincide with the initial diagnosis of ET and that treatment of ET (after diagnosis) markedly reduces, but does not annihilate, the chance of a second event occurring. […] A study that specifically focused on patients that were diagnosed with ET at a young age (i.e. a median age of 31 years) showed similar results compared to those in older adults, with arterial events (18%) being more common than venous events (6%), and cerebrovascular events (13%) more likely than coronary or peripheral embolisms (2% each).

• #34 Essential thrombocytosis: diagnosis, differential diagnosis, complications and treatment considerations of relevance for a cardiologist | springermedizin.de

  https://www.springermedizin.de/essential-thrombocytosis-diagnosis-differential-diagnosis-compli/24010900

  These numbers clearly indicate that thrombotic complications surpass haemorrhagic complications, that both types of events often coincide with the initial diagnosis of ET and that treatment of ET (after diagnosis) markedly reduces, but does not annihilate, the chance of a second event occurring. […] Both thrombotic and haemorrhagic complications have been observed in the setting of ET. […] Age (60 years), previous events, the presence of JAK2V617F, leukocytosis and long-term thrombocytosis have been identified as major risk factors for thromboembolic complications. […] Treatment of ET should be individualised, bearing in mind all possible complications of ET ranging from thrombotic and haemorrhagic events, the presence of risk factors, and the risk of progression to myelofibrosis or myeloid leukaemia.

• #35 Polycythemia Vera and Essential Thrombocythemia: Diagnosis, Risk-Stratification, Management Updates – Hematology Advisor

  https://www.hematologyadvisor.com/features/polycythemia-vera-essential-thrombocythemia-treatment-updates/

  The diagnosis of PV and ET is established on the basis of suspected clinical signs and symptoms, as well as laboratory findings, with bone marrow morphology as the mainstay of diagnosis. Practically, the detection of the JAK2 V617F mutation in peripheral blood is both sensitive and specific for differentiating PV from other causes of elevated hematocrit. […] When assessing thrombocytosis, the discovery of JAK2 V617F, CALR or MPL mutations verifies the presence of an underlying MPN. Conversely, the lack of these mutations does not eliminate the possibility of an MPN since ET can be classified as triple-negative. As a result, bone marrow evaluation is often needed to distinguish ET from other myeloid disorders, including prefibrotic primary myelofibrosis. […] The current risk stratification in PV includes 2 risk categories: High-risk (age 60 years or presence of thrombosis history) and Low-risk (absence of both factors).

• #36

  https://journals.lww.com/hemasphere/fulltext/2021/02000/low_risk_essential_thrombocythemia__a.6.aspx

  This model delineated patients into 3 risk groups according to an age 60 years (1 point), cardiovascular risk factors including tobacco use, hypertension, and diabetes mellitus (1 point), previous thrombosis (2 points), and JAK2 V617F positivity (2 points). […] In the United Kingdom, the conventional 2-tier system remains the most widely used risk stratification method and for the purpose of this review, low-risk patients are considered as those 60 years old with no previous thrombosis or hemorrhage (secondary to ET). […] In patients with unexplained, persistent, and significant thrombocytosis in whom JAK2, CALR, and MPL mutation and BCR-ABL1 fusion screening on peripheral blood are negative, bone marrow examination is also essential and can be conclusive in distinguishing from a reactive etiology.

• #37 Polycythemia Vera and Essential Thrombocythemia: Diagnosis, Risk-Stratification, Management Updates – Hematology Advisor

  https://www.hematologyadvisor.com/features/polycythemia-vera-essential-thrombocythemia-treatment-updates/

  While in ET, risk stratification is divided into 4 categories: Very low risk (age 60 years, no thrombosis history, JAK2 wild-type), Low risk (age 60 years, no thrombosis history, JAK2-mutant), Intermediate risk (age 60 years, no thrombosis history, JAK2 wild-type), High risk (thrombosis history or age 60 years, JAK2-mutant). […] The risk stratification model for both MPNs is designed to evaluate the probability of recurrent thrombotic complications.

• #38

  https://link.springer.com/article/10.1007/s12471-023-01757-4

  Both thrombotic and haemorrhagic complications have been observed in the setting of ET. […] Interestingly, many ET patients that present with an ACS have a normal CAG without signs of atherosclerosis, which supports the hypothesis that vascular events can be a direct result of the haematological problem, i.e. be unrelated to pre-existing atherosclerosis. […] Importantly, the presence of extreme thrombocytosis (platelets 1000109/l) was associated with a lower risk of thrombosis, possibly through the presence of acquired von Willebrand syndrome. […] Treatment of ET should be individualised, bearing in mind all possible complications of ET ranging from thrombotic and haemorrhagic events, the presence of risk factors, and the risk of progression to myelofibrosis or myeloid leukaemia. […] For clinicians in Europe, the European LeukemiaNET provides guidance based on the accumulating evidence with regard to optimal treatment.

• #39 How I Work up the Patient with Thrombocytosis – The ASCO Post

  https://ascopost.com/issues/march-15-2012/how-i-work-up-the-patient-with-thrombocytosis/

  Thrombocytosis is defined as a platelet count greater than 400 109/L. […] In managing the patient with thrombocytosis, one must first distinguish reactive from primary thrombocytosis. […] The presence of chronic thrombocytosis, thrombohemorrhagic complications, microvascular symptoms, or splenomegaly favors the diagnosis of primary thrombocytosis. […] However, clinical impression often requires confirmation through laboratory testing, which is also necessary to distinguish among the different causes of primary thrombocytosis (including essential thrombocythemia). […] JAK2V617F mutation screening is now part of the diagnostic workup for thrombocytosis, according to the World Health Organization (WHO) diagnostic criteria for essential thrombocythemia and polycythemia vera. […] Bone marrow morphology appears normal in reactive thrombocytosis. In clonal thrombocythemia, bone marrow findings include increased numbers of megakaryocytes and other myeloid cells, abnormality in cell morphology, presence of megakaryocyte clusters, and reticulin fibrosis.

• #40

  https://haematologica.org/article/view/haematol.2022.280917

  Among the 130 patients with triple-negative thrombocytosis, bone marrow biopsy led to a diagnosis of ET/MPN in 79, while in 45 patients, the biopsy was not in favor of MPN and in six the diagnosis was unclear (insufficient quality). […] Since a histological diagnosis between MPN and non-MPN may be subject to variability and some patients still had unclear diagnosis, we wondered whether a mutational analysis with targeted NGS of 24 genes commonly mutated in MPN could help with the diagnostic discrimination of patients. […] Overall, pathogenic/likely pathogenic variants were found slightly more frequently in patients considered as having MPN after bone marrow biopsy review (33 variants in 17/69 (25%) vs. 10 variants in 8/50 (16%) in non-MPN patients, P=not significant). […] In order to assess whether NGS data could better discriminate thrombocytosis patients with a higher risk of complications, we reclassified patients with an acquired pathogenic or likely pathogenic variant in the MPN group, irrespective of their histology.

• #41

  https://haematologica.org/article/view/haematol.2022.280917

  In conclusion, this study shows that characterization of triple-negative thrombocytosis relies on thorough clinical, biological, histological and genetic characterization. A relatively small panel of commonly mutated genes allows confirmation or challenges the initial assessment in as many as 20% patients each.

• #42 Visible–Near-Infrared Platelets Count: Towards Thrombocytosis Point-of-Care Diagnosis

  https://www.mdpi.com/2673-4583/5/1/78

  Thrombocytosis is a disorder with an excessive number of platelets in the blood, where total platelet counts (TPC) are crucial for diagnosis. […] This condition predisposes to blood vessels clotting and diseases such as stroke or heart attack. […] Monitoring coagulation risk is key in many health conditions, and point-of-care platforms would simplify this procedure by taking platelet counts to the bedside. […] The results show that TPC can be measured by visible–near-infrared spectroscopy above the standard error limit of 61.19 × 10^9 cells/L (R^2 = 0.7016), tested within the data range of 53 × 10^9 to 860 × 10^9 cells/L of dog blood. […] These results open the possibility for using spectroscopy as a diagnostic technology for the detection of high levels of platelets directly in whole blood, towards the rapid diagnosis of thrombocytosis and stroke prevention.

• #43 Visible–Near-Infrared Platelets Count: Towards Thrombocytosis Point-of-Care Diagnosis

  https://www.mdpi.com/2673-4583/5/1/78

  High PLT counts is a condition known as thrombocytosis, being attributed to abnormal bone marrow production or an ongoing condition such as anemia or inflammation. […] Thrombocytosis can result in blood clots, leading to life-threatening or impairing conditions such as heart attack or stroke. […] Despite the limitations shown in this feasibility study, PLT quantification using Vis–SWNIR spectroscopy in conjunction with the new SL-AI algorithm can attain a total error estimate of 25%. […] Vis–SWNIR POC technology based on SL-AI has shown high potential for PLT quantification and thrombocytosis diagnosis.

• #44 Secondary Thrombocytosis | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/30100

  Thrombocytosis, or thrombocythemia, occurs when the platelet count exceeds 450,000/L of blood. […] Secondary thrombocytosis, also known as reactive thrombocytosis, is characterized by an abnormally high platelet count due to underlying events, infections or diseases, or certain medications. […] In most cases, secondary thrombocytosis symptoms are due to an underlying disorder rather than the thrombocytosis itself. […] Approximately 80% to 90% of individuals with thrombocytosis are known to have secondary thrombocytosis. […] Secondary thrombocytosis resolves with treatment of the underlying etiology. […] Therefore, appropriate management should be initiated once the reactive condition, the causative factor, has been identified. […] Thrombocytosis, or thrombocythemia, is diagnosed through a complete blood count showing a platelet count greater than 450,000/L.

• #45 Thrombocytosis: Diagnostic Evaluation, Thrombotic Risk Stratification, and Risk-Based Management Strategies

  https://pmc.ncbi.nlm.nih.gov/articles/PMC3200282/

  The risk of thrombotic complications with reactive thrombocytosis is felt to be low, as 1.6% of patients with reactive thrombocytosis had thrombotic complications in one large case series. […] In clonal thrombocytosis, especially in ET and PV, thrombotic complications are a major cause of morbidity and mortality and the primary factor in determining treatment strategy. […] The rate of macrovascular thrombotic complications at diagnosis ranges 1125% in ET and 1239% in PV, with arterial thrombosis comprising the majority of events. […] The discovery of the JAK2V617F mutation has led to extensive evaluation to determine whether those carrying this mutation have a different disease phenotype than those who are JAK2 wild type, and this evaluation has included examining the risk of thrombosis in both groups.

• #46 Essential thrombocytosis: diagnosis, differential diagnosis, complications and treatment considerations of relevance for a cardiologist | springermedizin.de

  https://www.springermedizin.de/essential-thrombocytosis-diagnosis-differential-diagnosis-compli/24010900

  For the prevention of thrombotic complications in ET, the advocated approach, based on risk stratification by a history of (arterial or venous) thrombosis, age 60 years, the presence of a JAK2 mutation and cardiovascular risk factors, is presented in Tab. 3. […] In a large retrospective study of patients with primary thrombocytosis who received either antiplatelet agents, anticoagulation, cytoreductive treatment or underwent phlebotomy after a first thromboembolic complication, only cytoreductive therapy resulted in a significant reduction in recurrent ACS. […] With regard to the treatment of ACS in the setting of ET, thrombus aspiration, intracoronary thrombolysis, balloon angioplasty, stent placement, coronary bypass grafting (CABG) and systemic fibrinolytic/thrombolytic treatment have all been described.

• #47 Essential thrombocythemia diagnosis – Cancer Therapy Advisor

  https://www.cancertherapyadvisor.com/home/decision-support-in-medicine/hospital-medicine/essential-thrombocythemia-3/

  Rarely ET may progress to an acute leukemia (rates vary from 0.6-5% transformation) or myelofibrosis. M4 or M7 phenotype is the most common type of AML if blastic transformation occurs. Karyotypic abnormalities may also predispose to the progression of AML. […] Smoking may increase the risk of thromboembolic events, thus cessation is advised.

• #48 Essential Thrombocythemia – Hematology and Oncology – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/hematology-and-oncology/myeloproliferative-disorders/essential-thrombocythemia

  The diagnosis is suggested by normal hematocrit, white blood cell count, mean corpuscular volume (MCV), and iron studies, as well as absence of the BCR-ABL translocation. […] Genetic studies should be done, including a quantitative JAK2 V617F assay (by next-generation sequencing [NGS] or quantitative polymerase chain reaction), along with a BCR-ABL assay to exclude chronic myeloid leukemia (CML, which can manifest with thrombocytosis alone). […] Patients who do not have JAK2 V617F, CALR, or MPL gene mutations (called triple negative) are rare. […] Mutation analysis should always be quantitative because the driver gene allele burden in JAK2 V617F-positive essential thrombocythemia does not exceed 50%. […] World Health Organization guidelines suggest that a bone marrow biopsy showing increased numbers of enlarged, mature megakaryocytes is required for a diagnosis of essential thrombocythemia, but this criterion has never been validated prospectively, and a marrow examination will not distinguish essential thrombocythemia from polycythemia vera.

• #49 A Review of Essential Thrombocythemia and Its Complications – Hematology & Oncology

  https://www.hematologyandoncology.net/archives/february-2023/a-review-of-essential-thrombocythemia-and-its-complications/

  Although the detection of JAK2 V617F, CALR, or MPL mutations confirms the presence of MPN, their absence does not rule it out because 20% of ET cases can be triple-negative. […] Therefore, a bone marrow examination is often necessary to make an accurate morphologic diagnosis of ET and distinguish it from prefibrotic PMF and PV.

• #50 Thrombocytosis: Diagnostic Evaluation, Thrombotic Risk Stratification, and Risk-Based Management Strategies

  https://pmc.ncbi.nlm.nih.gov/articles/PMC3200282/

  In general, causes of thrombocytosis can be described as spurious, reactive, or clonal in nature. […] Once the diagnosis of thrombocytosis is confirmed by peripheral blood smear review, the diagnostic evaluation turns to determining whether the process is reactive or clonal in nature. […] The presence of a potential cause of reactive thrombocytosis does not rule out a concomitant clonal process, especially in persistent thrombocytosis. […] Once a reactive thrombocytosis is excluded and thrombocytosis is persistent, the diagnostic evaluation should turn to distinguishing between the various causes of clonal thrombocytosis. […] The classic myeloproliferative neoplasms (MPNs), comprised of essential thrombocythemia (ET), chronic myeloid leukemia (CML), polycythemia vera (PV), and primary myelofibrosis (PMF) are the most common clonal processes associated with thrombocytosis.

• #51 Essential thrombocytosis: diagnosis, differential diagnosis, complications and treatment considerations of relevance for a cardiologist | mijn-bsl

  https://mijn.bsl.nl/essential-thrombocytosis-diagnosis-differential-diagnosis-compli/24011868

  In clinical practice 8090% of subjects with a platelet count above 450109/l do not have an essential/primary thrombocytosis, but have secondary/reactive thrombocytosis, which is an abnormally high platelet count secondary to underlying events, disease or medication. […] In the case of secondary thrombocytosis, the platelet count is rarely 1000109/l. […] Another, in fact erroneous, cause of thrombocytosis may result from the use of automated analysers. […] Hence, a peripheral blood smear might also differentiate primary/essential from artefactual/spurious thrombocytosis. […] Overall rates of complications in various regions/settings and using different definitions of events during long-term follow-up in patients with ET are relatively high. […] The incidence of thrombotic complications ranges from 9% to 84% at diagnosis and from 7% to 32% during long-term follow-up.

• #52 Thrombocytosis: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/13350-thrombocytosis

  Tests may include: Peripheral blood smear: Shows if the platelets in your blood look abnormal. DNA/genetic tests: Detect gene mutations common in ET, like JAK2. Bone marrow biopsy: Checks for abnormal cells in your bone marrow. […] If you dont have symptoms, you may only need routine checkups. Secondary forms of thrombocytosis rarely require treatment. Usually, levels return to normal after the condition causing high platelets (injury, infection, response to surgery, etc.) resolves. […] Theres no cure for essential thrombocytosis, but your healthcare provider can help you manage the condition to reduce your risk of clots. High platelet levels associated with secondary causes usually return to normal once the underlying condition resolves. […] High platelets arent life-threatening, but the complications that can result from the condition blood clots or severe bleeding can be. The most common causes of thrombocytosis are short-lived and dont put you at risk of serious blood clots. The risk is greater with essential thrombocytosis.

• #53 Thrombocytosis: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/13350-thrombocytosis

  Reactive thrombocytosis gets better when the underlying problem resolves. Although your platelet count is elevated for a short time (or even long-term after splenectomy), secondary thrombocytosis doesnt typically lead to abnormal blood clotting. Essential thrombocythemia (ET), or primary thrombocytosis, can cause serious bleeding or clotting complications. Taking medicine that keeps your platelet levels normal can help prevent this. […] Dont be alarmed if your blood work results show high platelet levels. Your platelets may be elevated for various reasons. Many causes dont require treatment. If your levels remain high and youre experiencing symptoms, your healthcare provider will work to determine the cause. Careful monitoring and medications can usually prevent the most concerning complications associated with thrombocytosis.

• #54 Platelet Disorders – Thrombocythemia and Thrombocytosis | NHLBI, NIH

  https://www.nhlbi.nih.gov/health/thrombocythemia-thrombocytosis

  Treatment for thrombocythemia may include medicines and procedures. […] You may need one of the following medicines to lower your platelet count. […] Plateletpheresis is a procedure used to quickly lower your platelet count. […] Thrombocythemia and thrombocytosis may cause blood clots which can block blood flow to your organs.

• #55 Essential thrombocythemia | Canadian Cancer Society

  https://cancer.ca/en/cancer-information/cancer-types/leukemia/what-is-leukemia/myeloproliferative-neoplasms/essential-thrombocythemia

  Many tests used to diagnose ET are used to diagnose leukemia. Diagnosis of ET is usually based on if the platelet count in the blood is high, if the bone marrow has a lot of platelet-forming cells (called megakaryocytes) and if JAK2, CALR or MPL gene mutations are found in the blood or bone marrow. […] ET may not cause any symptoms. If you do have symptoms, they are often related to either blood clots or bleeding problems. The most common symptoms of ET include: […] Low-dose Aspirin may be offered for low-risk ET if you have a JAK2 mutation or cardiovascular risk factors (including obesity, smoking tobacco, high blood pressure or high cholesterol) or both. […] If you have intermediate or high-risk ET you may be offered drug therapy. The drugs used most often to treat ET include: […] Low-dose Aspirin is usually given with drug therapy unless you have a symptom or condition that increases your risk of bleeding.

• #56

  https://link.springer.com/article/10.1007/s12471-023-01757-4

  With regard to the prevention of thrombotic complications in ET, the advocated approach, based on risk stratification by a history of (arterial or venous) thrombosis, age 60 years, the presence of a JAK2 mutation and cardiovascular risk factors, is presented in Tab. 3. […] An alternative way to prevent recurrent arterial events might be the use of more aggressive, e.g. double antiplatelet, therapy in the first 34 years following an arterial thrombotic event. […] The main problem with regard to percutaneous coronary interventions (PCIs) in ET patients lies in the choice of antiplatelet regimen due to the high risk of in-stent thrombosis associated with thrombopathy. […] Hence, it has been argued that revascularisation in patients with a platelet count 400600109/l should be discussed in a multidisciplinary team, taking both the risk of thrombosis and progressive ischaemia into account.

• #57 Orphanet: Essential thrombocythemia

  https://www.orpha.net/en/disease/detail/3318

  Management is currently based on the risk of thrombosis, and may involve anti-aggregation therapy and/or platelet cytoreduction. Hydroxycarbamide and aspirin are effective in high risk patients. Anagrelide is approved in European Union as platelet lowering agent in patients resistant or intolerant to hydroxycarbamide. Conventional and pegylated recombinant interferon alpha (IFN) are effective in controlling platelet counts, although there is no evidence of efficacy in preventing thrombosis and could be preferred to conventional cytoreductive therapies in younger patients. Risk factors associated with arteriosclerotic disease (hypertension, diabetes, smoking etc) must be actively managed. Conventional cytoreductive therapies are contra-indicated in pregnancy.

• #58 Testing for essential thrombocythaemia | Blood Cancer UK

  https://bloodcancer.org.uk/understanding-blood-cancer/essential-thrombocythaemia-et/et-testing/

  These tests are done using a sample of your blood, which is analysed in a laboratory. Doctors are looking for changes to genes called JAK2, CALR or MPL. Abnormalities in these genes may suggest you have ET. […] You may need a bone marrow biopsy to diagnose ET. This is a minor surgical procedure used to collect samples of bone marrow to test in the laboratory. […] Doctors will examine your samples under the microscope to check how the bone marrow looks. This includes checking if your megakaryocytes (the cells that produce platelets) look abnormal. […] You may not need a bone marrow biopsy if blood tests confirm that ET is the correct diagnosis. However, you may need one to check on your progress from time to time if you have treatment for ET. […] In general, people with ET have a higher risk of thrombosis (blood clots) and haemorrhage (bleeding). […] After you have been diagnosed with ET, you may have tests to monitor the condition and any treatment you’re having. These tests include: full blood count (FBC), bone marrow biopsy, a physical examination of your spleen or ultrasound scan.

• #59 Essential thrombocytosis: diagnosis, differential diagnosis, complications and treatment considerations of relevance for a cardiologist | mijn-bsl

  https://mijn.bsl.nl/essential-thrombocytosis-diagnosis-differential-diagnosis-compli/24011868

  These numbers clearly indicate that thrombotic complications surpass haemorrhagic complications, that both types of events often coincide with the initial diagnosis of ET and that treatment of ET (after diagnosis) markedly reduces, but does not annihilate, the chance of a second event occurring. […] Although ET is a rare haematological malignancy, its prevalence is much higher in patients presenting with either thrombotic or haemorrhagic events, such as patients seen by a cardiologist, neurologist or vascular surgeon. […] Any specialist should be aware of such underlying pathology and thus actively screen for elevated thrombocytes (i.e. a platelet count 450109/l) in patients presenting with either thrombotic or haemorrhagic events, notably in those without concomitant CV risk factors.

• #60 Essential thrombocytosis: diagnosis, differential diagnosis, complications and treatment considerations of relevance for a cardiologist | springermedizin.de

  https://www.springermedizin.de/essential-thrombocytosis-diagnosis-differential-diagnosis-compli/24010900

  The optimal choice of intervention and the timing thereof should be on an individual basis, taking the presence of spasm, thrombus, atherosclerosis, ongoing ischaemia and concurrent platelet counts into account. […] Although ET is a rare haematological malignancy, its prevalence is much higher in patients presenting with either thrombotic or haemorrhagic events, such as patients seen by a cardiologist, neurologist or vascular surgeon.

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