Myeloproliferative disorders Flashcards
What is myelofibrosis?
A myeloproliferative disorder thought to be caused by hyperplasia of abnormal megakaryocytes.
What stimulates fibroblasts in myelofibrosis?
The resultant release of platelet derived growth factor is thought to stimulate fibroblasts.
Where does haematopoiesis develop in myelofibrosis?
Haematopoiesis develops in the liver and spleen.
What are common symptoms of myelofibrosis?
Elderly person with symptoms of anaemia, such as fatigue (the most common presenting symptom), massive splenomegaly, and hypermetabolic symptoms like weight loss and night sweats.
What are the laboratory findings in myelofibrosis?
Anaemia, high WBC and platelet count early in the disease, ‘tear-drop’ poikilocytes on blood film, unobtainable bone marrow biopsy - ‘dry tap’ therefore trephine biopsy needed, high urate and LDH (reflect increased cell turnover).
What is thrombocytosis?
Thrombocytosis is an abnormally high platelet count, usually > 400 * 10^9/l.
What are the causes of thrombocytosis?
Causes include reactive thrombocytosis due to stress (e.g., severe infection, surgery), iron deficiency anemia, malignancy, essential thrombocytosis, and hyposplenism.
What is essential thrombocytosis?
Essential thrombocytosis is a myeloproliferative disorder characterized by megakaryocyte proliferation and overproduction of platelets.
What are the features of essential thrombocytosis?
Features include a platelet count > 600 * 10^9/l, thrombosis and hemorrhage, a burning sensation in the hands, and a JAK2 mutation in around 50% of patients.
How is essential thrombocytosis managed?
Management includes hydroxyurea (hydroxycarbamide) to reduce platelet count, interferon-α for younger patients, and low-dose aspirin to reduce thrombotic risk.
