Smp

group of clonal stem cell disorders characterized by aberrant regulation of proliferation that results in excess production of myeloid elements in the bone marrow.
characterized by overproduction of platelets. Patients overproduction of erythrocytes, although myeloid cells usually present in the fifth and sixth decades of life and megakaryocytes are also affected.
with a platelet count > than 600,000/µL Signs and symptoms include ruddy cyanosis, Patients have signs and symptoms of anemia plus night hypertension, splenomegaly, headache, sweating, sweats and weight loss. The peripheral blood smear weight loss, paresthesias, and dizziness. Generalized shows marked leukoerythroblastic findings with tear pruritus occurs in up to 50% of patients and is drop–shaped erythrocytes and megathrombocytes. Approximately 50% of patients are asymptomatic exacerbated by exposure to hot water (typically a hot bath The bone marrow aspirate is often “dry” (unsuccess- or shower). Thrombotic disorders (erythromelalgia, small-vessel thrombosis that causes erythromelal- ful aspirate), and bone marrow biopsy shows marked transient ischemic attacks, myocardial infarction or gia (burning and paresthesias of the extremities fibrosis. The fibrosis causes decreased bone marrow stroke, deep venous thrombosis, and Budd-Chiari that are exacerbated by heat) or central nervous reserve and extramedullary hematopoiesis with massive system thrombosis, such as migraine headaches, syndrome) are the most serious presenting signs of the hepatosplenomegaly. As the disease progresses, transient ischemic attacks, scotomas, amaurosis disease and occur in about two thirds of patients with patients experience bone marrow failure, portal fugax (transient monocular or binocular vision polycythemia vera. Thrombosis is due to the elevated red hypertension (9% to 18% of patients), and pulmonary blood cell mass and increased whole blood viscosity and is aggravated by concomitant thrombocytosis in 50% of hypertension (due to ectopic myeloid metaplasia, Large-vessel thrombosis, such as renal vein patients and leukocytosis in 75% of patients. The risk of thromboembolic disease, or pulmonary fibrosis that occurs thrombosis or Budd-Chiari syndrome, may also occur.
thrombosis increases with increasing age, although even in response to cytokines released by the circulating young patients can present with life-threatening thrombotic The diagnosis of essential thrombocythemia is one of events. Patients who require surgery are at high risk for both thrombosis and hemorrhage in the postoperative Although there is no curative treatment for myelofibrosis, HSCT has been effective in a small Therapy for essential thrombocythemia depends on number of patients and should be considered for patients Determination of the red blood cell mass is not younger than 60 years of age. HSCT has significant risks, thrombocytosis, and the medical history. The needed for patients with a hematocrit level greater however. The 1-year transplant-related mortality rate is as platelet count must be lowered quickly in patients than 60% in men and 56% in women. However, high as 25%, with a 5-year survival rate of 48%.
with life-threatening symptoms, such as a transient patients who have a slightly elevated hematocrit ischemic attack, stroke, myocardial infarction, or level and all patients with the Budd-Chiari syndrome cytoreduction with hydroxyurea to control the elevated gastrointestinal bleeding. Platelet apheresis along should be evaluated for polycythemia vera with a leukocyte and platelet counts or interferon alfa to control with cytoreductive therapy is indicated for these nuclear medicine measurement of the red blood cell the thrombocytosis, splenomegaly, and bone marrow mass and plasma volume measurement to monitor fibrosis. Many patients require repeated transfusions, myelosuppressive agent of choice in this setting for a depressed serum erythropoietin level. JAK2 which may lead to chronic iron overload and the need for because of its rapid onset of action. For patients V617F mutation testing should also be done with less urgent symptoms, myelosuppression is because polycythemia vera is diagnosed in up to iron chelation therapy. Androgen therapy controls instituted with lower doses of hydroxyurea, 40% of patients with Budd-Chiari syndrome.
hypoproliferative anemia in up to 50% of patients. anagrelide, or interferon alfa plus low-dose Thrombocytopenia due to hypersplenism or decreased Treatment of polycythemia vera is directed toward aspirin. Since smoking can increase the risk of platelet production is managed with platelet reducing the red blood cell mass and preventing thrombosis, patients should be encouraged to stop. thrombosis. Therapeutic phlebotomy should be instituted transfusions. It is important to avoid alloimmunization Erythromelalgia responds rapidly to low-dose with the goal of lowering the hematocrit level to less than caused by repeated transfusions by using a restrictive aspirin, and a single dose can relieve symptoms for 42% in women and less than 45% in men. Low-dose transfusion approach and by transfusing only several days. Asymptomatic patients can be aspirin is indicated unless the patient has symptoms of leukodepleted blood products. Hyperuricemia is treated easy bruising and an acquired platelet disorder. with allopurinol. Massive hypersplenism may be Hyperuricemia is treated with allopurinol, and patients managed with low-dose radiation therapy, but the The prognosis is good for patients with essential with pruritus are given antihistamines. Interferon alfa, response is transient and can be complicated by the loss thrombocythemia. A large Spanish study published in anagrelide, and/or hydroxyurea is the treatment of of extramedullary hematopoiesis with resulting cytopenia. 1991 showed no significant difference in longevity choice for older symptomatic patients with polycythemia between patients with this disorder and controls. vera that cannot be control ed with phlebotomy and Transformation to other myeloproliferative disorders Survival after diagnosis of myelofibrosis ranges from 1 does occur, however, and 8% of patients will year to over 30 years, but the median survival is only 5 Prognosis depends on the severity of the develop myelofibrosis over a 10-year period. A complications of the disease. Median survival after years. Prognostic indicators have not been reproducible smaller number of patients will develop polycythemia diagnosis ranges from less than 2 years to more than among different studies, but significant anemia at 15 years. Death is usually due to thrombosis, but presentation is a reliably poor prognostic finding patients may develop serious bleeding abnormalities, myelofibrosis, or acute myeloid leukemia.
Myeloproliferative Disorders.mmap - 11.05.12 - Mindjet

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