Essential thrombocythemia (NORD)
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Essential thrombocythemia (NORD)
Hematological system
Anemias
Iron deficiency anemia
Beta-thalassemia
Alpha-thalassemia
Sideroblastic anemia
Anemia of chronic disease
Lead poisoning
Hemolytic disease of the newborn
Glucose-6-phosphate dehydrogenase (G6PD) deficiency
Autoimmune hemolytic anemia
Pyruvate kinase deficiency
Paroxysmal nocturnal hemoglobinuria
Sickle cell disease (NORD)
Hereditary spherocytosis
Anemia of chronic disease
Aplastic anemia
Fanconi anemia
Megaloblastic anemia
Folate (Vitamin B9) deficiency
Vitamin B12 deficiency
Fanconi anemia
Diamond-Blackfan anemia
Heme synthesis disorders
Acute intermittent porphyria
Porphyria cutanea tarda
Lead poisoning
Coagulation disorders
Hemophilia
Vitamin K deficiency
Platelet disorders
Bernard-Soulier syndrome
Glanzmann's thrombasthenia
Hemolytic-uremic syndrome
Immune thrombocytopenic purpura
Thrombotic thrombocytopenic purpura
Mixed platelet and coagulation disorders
Von Willebrand disease
Disseminated intravascular coagulation
Heparin-induced thrombocytopenia
Thrombosis syndromes (hypercoagulability)
Antithrombin III deficiency
Factor V Leiden
Protein C deficiency
Protein S deficiency
Antiphospholipid syndrome
Lymphomas
Hodgkin lymphoma
Non-Hodgkin lymphoma
Leukemias
Chronic leukemia
Acute leukemia
Leukemoid reaction
Leukemoid reaction
Dysplastic and proliferative disorders
Myelodysplastic syndromes
Polycythemia vera (NORD)
Myelofibrosis (NORD)
Essential thrombocythemia (NORD)
Langerhans cell histiocytosis
Mastocytosis (NORD)
Plasma cell dyscrasias
Multiple myeloma
Monoclonal gammopathy of undetermined significance
Waldenstrom macroglobulinemia
Hematological system pathology review
Microcytic anemia: Pathology review
Non-hemolytic normocytic anemia: Pathology review
Intrinsic hemolytic normocytic anemia: Pathology review
Extrinsic hemolytic normocytic anemia: Pathology review
Macrocytic anemia: Pathology review
Heme synthesis disorders: Pathology review
Coagulation disorders: Pathology review
Platelet disorders: Pathology review
Mixed platelet and coagulation disorders: Pathology review
Thrombosis syndromes (hypercoagulability): Pathology review
Lymphomas: Pathology review
Leukemias: Pathology review
Plasma cell disorders: Pathology review
Myeloproliferative disorders: Pathology review
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Essential thrombocythemia (NORD)
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Essential thrombocythemia (NORD)
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USMLE® Step 1 style questions USMLE
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| Laboratory value | Result |
| Hemoglobin | 9.5 g/dL |
| Hematocrit | 28.5% |
| Leukocytes | 2,700/mm3 |
| Platelets | 100,000/mm3 |
Biopsy of the bone marrow biopsy shows increased fibrosis and reduced cell count. Polymerase chain reaction testing reveals a mutation in a gene encoding for a non-receptor tyrosine kinase. Which of the following diseases is also caused by an identical mutation?
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Bleeding
essential thrombocythemia p. 441
Essential thrombocythemia p. 441
Thrombosis
essential thrombocythemia p. 441
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Transcript
Content Reviewers
Rishi Desai, MD, MPHContributors
Stefan Stoisavljevic, MD
Alex Aranda
Essential thrombocythemia is a slowly progressive disease where the bone marrow produces too many platelets.
In rare cases, essential thrombocythemia can develop into myelofibrosis and acute leukemia.
Now, the vast majority of bone marrow is made of hematopoietic cells which are the early progenitor cells that can differentiate into other cell types.
In the case of platelets, progenitor cells differentiate into megakaryocytes, which are responsible for creating platelets.
In essential thrombocythemia there’s a genetic mutation that occurs in the Janus Kinase 2 gene, also called JAK2, or somewhere along this pathway of cell signalling.
Normally, the liver and kidneys produce a a tiny hormone called thrombopoietin which binds to hematopoietic cell receptors.
When it binds, those cells activate the JAK2 gene which makes them divide and mature into megakaryocytes and platelets.
Cells can also develop mutations in the thrombopoietin receptor, MPL, or in the chaperone protein, Calreticulin or CalR.
Now, when there’s a genetic mutation in CalR, the signalling pathway remains active all the time, and that means that platelets keep getting produced even in the absence of thrombopoietin.
Although there are lots of platelets that are made, many of them end up being misshapen - they’re large and irregularly shaped.
Now, all of these excess platelets end up causing an increased risk of blood clots in the deep veins of the legs, lungs, and even sites where clots don’t usually form, like the abdomen.
As a result, there’s an increased risk of stroke, heart attack, and miscarriage.
Now, if the number of platelets is extremely high, over 1.5 million, then there’s an increased risk of bleeding.
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