PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “HEMORRHAGIC THROMBOCYTHEMIA”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed2001

A single institutional experience with 43 pregnancies in essential thrombocythemia.

OBJECTIVES: We describe the periconception circumstances and outcome of 43 consecutive pregnancies in an unselected group of young women with essential thrombocythemia (ET). PATIENTS AND METHODS: We retrospectively studied 74 consecutive cases of young women with ET seen at our institution, among whom 43 pregnancies occurred in 20 patients. RESULTS: Of the 43 pregnancies, 22 (51%) were successful (21 term and 1 preterm live births) and 21 (49%) ended in miscarriages (1 ectopic pregnancy, 2 elective abortions, 16 first-trimester spontaneous abortions, 1 stillbirth at 22 wk, and 1 abruptio placentae at 33 wk). Management of ET at the time of conception included either no specific therapy (16 cases) or the use of aspirin alone (24 cases), a cytoreductive agent (2 cases), or heparin (1 case). There were no significant differences with respect to platelet count or the effect of treatment with aspirin, either at the time of conception or during the first trimester, among cases of successful pregnancies (22), all miscarriages (21), or first-trimester spontaneous abortions (16). The findings were similar when the analysis was restricted to only first-time pregnancies. In patients with multiple pregnancies, the outcome of a subsequent pregnancy was not predicted by the outcome of the first. In general, in successful cases the last two trimesters were mostly uneventful, with healthy offspring being reported in all cases. CONCLUSIONS: Pregnant patients with ET have an increased risk of first-trimester abortion which is not predictable by preconception platelet count or aspirin therapy. In addition, our experience does not support the use of prophylactic platelet apheresis during delivery.

Abortion, Induced↗
PubMed1997

Relation of platelet abnormalities to thrombosis and hemorrhage in chronic myeloproliferative disorders.

The chronic myeloproliferative disorders (MPD), predominantly polycythemia vera and essential thrombocythemia, are characterized by a high incidence of thromboembolic and, to a lesser degree, hemorrhagic complications. The disease process in chronic MPD affects a pluripotent progenitor cell and results in trilineage hematopoietic proliferation. Clonal involvement of megakaryocytopoiesis is regarded as the main origin of thromboembolism in MPD and results in abnormal platelet production. These platelets show increased size heterogeneity and ultrastructural abnormalities, and their function in vitro is in many ways impaired with a high degree of individual variability. Elevated levels of platelet-specific proteins, increased thromboxane generation, and expression of activation-dependent epitopes on the platelet surface are common on chronic MPD, and may reflect an inappropriate state of platelet activation. Although a variety of platelet receptor deficiencies and some defects of intracellular signaling pathways have been identified, the different platelet defects in MPD could not be traced back to an underlying general pathogenetic mechanism. On progression of chronic MPD to more advanced stages of the disease, the number of platelet abnormalities tend to increase. Cytoreductive drugs may partly improve platelet dysfunction, and platelet inhibitory agents reduce symptoms of platelet activation. However, neither of these therapeutic principles is able to normalize platelet function in MPD. As an alternative to conventional treatment, specific suppression of clonal megakaryocyte growth and recovery of polyclonal hematopoiesis may be achieved by biologic agents such as interferon alpha. Such treatment strategies may prevent thromboembolic complications together with hematologic symptoms and progression of the disease and should be further evaluated in prospective studies.

Alkylating Agents↗
PubMed1994

Platelet disorders in pregnancy: implications for mother and fetus.

Platelet disorders in pregnancy are not uncommon. Most often, obstetricians are faced with a patient with undiagnosed thrombocytopenia and have the responsibility of deciding if the condition is ITP, gestational thrombocytopenia, or a process related to pre-eclampsia. Correct diagnosis is important because ITP can be associated with fetal thrombocytopenia, making route of delivery important. In alloimmune thrombocytopenia, the mother develops antibodies to a specific platelet antigen present on the fetal platelet but absent on her own. Severe AIT can cause intracranial hemorrhage and have disastrous consequences for the fetus and neonate. In preliminary studies antenatal intravenous gamma globulin therapy has shown promise in preventing the development of intracranial hemorrhage and ameliorating fetal thrombocytopenia. Essential thrombocythemia with a platelet count of greater than 600 x 10(9) platelet/L can occur in pregnancy; therapy consists of antiplatelet aggregating agents such as aspirin, and plateletpheresis. Platelet function disorders can be acquired or inherited. Acquired platelet dysfunction disorders are usually caused by drugs such as aspirin or indomethacin, or by a systemic disease. Hereditary disorders of platelet function can be diagnosed in utero, but cordocentesis may represent an unacceptably high risk. For prenatal diagnosis, other methods, such as chorionic villus sampling or amniocentesis, should be investigated as an alternative to the potentially high risk of cordocentesis.

Autoimmune Diseases↗
PubMed1994

Chronic toxicity studies of piperonyl butoxide in F344 rats: induction of hepatocellular carcinoma.

Male and female F344 rats (30-33 rats/group) were administered piperonyl butoxide (alpha-[2-(2-butoxyethoxy)ethoxy]-4,5-methylenedioxy-2-propylto luene) in the diet at levels of 0 (control), 0.6, 1.2, and 2.4% for nearly 2 years. Beginning at about 40 weeks, 10 rats in the 1.2% treated male group died due to cecal hemorrhages. Piperonyl butoxide induced hepatocellular carcinoma in both sexes in a dose-dependent manner. Hepatocellular carcinoma was found even in the 1.2% treated male group (incidence, 26.7%), and incidences in the 2.4% groups of males and females were 80.0 and 57.7% respectively of all those surviving. Piperonyl butoxide also caused essential thrombocythemia with a dose-response relationship. Hemorrhages in stomach and cecum, anemia, degenerative lesions of alveoli, and nephrotoxicity were also observed related to exposure. These results indicate that piperonyl butoxide is a hepatocarcinogen to the rat.

Animals↗
PubMed1990

Incidence and risk factors for thrombotic complications in a historical cohort of 100 patients with essential thrombocythemia.

The purpose of this study was to determine which factors were associated with an increased risk of thrombo-hemorrhagic complications in a historical cohort of 100 consecutive and unselected patients with essential thrombocythemia (ET) in whom busulfan treatment was given when platelets were more than 1,000 x 10(9)/L and/or a major thrombotic or hemorrhagic event occurred. The incidence of major hemorrhagic complications was very low (0.33%/person-time at risk [pt-yr]) in comparison with that of thrombotic episodes (6.6%/pt-yr). In an adequate and appropriate control historical group of 200 patients, no severe hemorrhages were recorded and the incidence of thrombotic events was 1.2% pt-yr. Thus, the analysis of risk factors was restricted to this latter group of events. Age, a previous thrombotic event, and long duration of thrombocytosis were identified as major risk factors for thrombosis, while smoking, diabetes mellitus, hyperlipidemia, and hypertension did not influence the rate of thrombotic episodes.

Adolescent↗
PubMed1991

Cutaneous manifestations in patients with essential thrombocythemia.

In a retrospective study of 268 patients with essential thrombocythemia, related cutaneous manifestations were found in 58 (22%). In 27 cases (10%) the related skin lesions were present at the time of the primary diagnosis of essential thrombocythemia. Hematomas, ecchymoses, petechiae, or purpura occurred in 24 (41%) of the 58 patients. Fifteen patients (26%) had erythromelalgia, in 11 of whom it was the initial complaint. Livedo reticularis, recurrent superficial thrombophlebitis, ischemic complications with gangrene, leg ulcers, or ulcers on the toes were other manifestations. Urticaria occurred in two patients, and Raynaud's phenomenon and necrotizing vasculitis were each observed in one patient. Platelet function may be abnormal, and this was found in 13 of 19 patients studied, 9 of whom had spontaneous platelet aggregation. Knowledge of the cutaneous manifestations in essential thrombocythemia may lead to its earlier detection. Prompt diagnosis of essential thrombocythemia is important because treatment may prevent severe hemorrhagic or thrombotic events.

Adult↗
PubMed2005

Platelets and thrombosis in myeloproliferative diseases.

The myeloproliferative disorders have been the "poor cousins" in the family of hematological malignancies for some time. Recently this field has advanced considerably with the description of a mutation in the JAK2 kinase detectable in the majority of patients and the publication of two landmark clinical trials--ECLAP and MRC PT1. But although both ECLAP and MRC PT1 inform clinical management and allude to the complexities of thrombosis we still lack fundamental knowledge, and our understanding of thrombosis in these conditions has not paralleled advances in the field of thrombosis and vascular biology. The predominant clinical complications of essential thrombocythemia and polycythemia vera are thrombotic and hemorrhagic; these significantly impact upon prognosis and quality of life. Here the current status of our knowledge is reviewed with specific emphasis upon the role of the platelet in the pathogenesis of thrombosis as well as the impact of recent data from ECLAP and MRC PT1.

Aspirin↗
PubMedDate not supplied

Essential thrombocythemia-related acute ST-segment elevation myocardial infarction. A case report and literature review.

Essential thrombocythemia is a clonal disorder of the myeloid stem cell that causes pathologic expansion of the megakaryocytic elements in the bone marrow, with a persistent increase in the platelet count. The disease is associated with an elevated risk of thrombosis, hemorrhage, and vasomotor symptoms. The presenting features of essential thrombocythemia can range from being asymptomatic to thrombohemorrhagic complications including acute myocardial infarction. Acute ST-segment elevation myocardial infarction due to left main trunk and ostial left anterior descending coronary artery lesions was diagnosed in a young 31-year-old man. Platelet count was markedly increased and essential thrombocythemia was also diagnosed. Because of left main disease, primary coronary intervention was not feasible and an emergent coronary artery bypass grafting was performed along with pharmacologic management of essential thrombocythemia. The early postoperative period was complicated by acute pulmonary embolism. Hydroxyurea and anagrelide were administered postoperatively, resulting in the decrease of platelet count. A succinct review of myocardial infarction in patients with essential thrombocythemia is presented, and therapeutic strategies in such patients are discussed.

Adult↗
PubMed2006

Clinicopathological criteria for differential diagnosis of thrombocythemias in various myeloproliferative disorders.

Thrombocythemias with the presenting or developing complications of thromboembolic and hemorrhagic episodes may be encountered at strikingly different incidences in each subtype of chronic myeloproliferative disorders. A critical reappraisal of the Polycythemia Vera Study Group (PVSG) criteria for essential thrombocythemia (ET) reveals that differentiation is explicitly focused on the exclusion of chronic myeloid leukemia and polycythemia vera (PV), but not on prodromal stages of chronic idiopathic myelofibrosis (CIMF) or latent (initial) PV. Consequently, it may be assumed that most series of patients with so-called ET include a considerable fraction of patients with the latter entities. The diagnostic impact of bone marrow (BM) histopathology was recognized by the World Health Organization classification, which emphasizes for the first time positive criteria for ET. The need of a more accurate ET diagnosis is obvious, in particular regarding therapeutic strategies and outcome (i.e., progression into myelofibrosis and blastic crisis). Conversely, early CIMF with accompanying thrombocythemia mimicking (true) ET is characterized by a higher rate of evolution into myelofibrosis and fatal complications. A scrutinized discrimination of thrombocythemias resulting in a clear-cut diagnosis of true versus false ET is warranted by a professional evaluation of BM biopsies in ongoing and prospective clinical trials.

Diagnosis, Differential↗
PubMed1997

Thrombotic complications in essential thrombocythemia with relatively low platelet counts.

Essential thrombocythemia (ET) is often associated with thrombotic and hemorrhagic complications, mostly at platelet counts exceeding 600 x 10(9)/L. There are, however, a few reports of such complications in ET at considerably lower platelet levels and the therapeutic approach to affected patients with relatively low platelet counts is still controversial. In the present study, the first to directly address the issue of hemostatic manifestations at relatively low platelet counts, we have determined the lowest platelet counts associated with such manifestations in 56 consecutive ET patients. Clinical manifestations related to ET were recorded in 46 (82%) patients. Of the symptomatic patients, 32 (70%) had symptoms at platelet counts lower than 600 x 10(9)/L, 23 (50%) at counts lower than 500 x 10(9)/L, 10 (22%) at counts lower than 400 x 10(9)/L, and 6 patients (13%) at platelet counts as low as 300-350 x 10(9)/L. Severe complications occurred at platelet counts lower than 600 x 10(9)/L in 10 patients (22%), lower than 500 x 10(9)/L in 7 (15%), and at lower than 400 x 10(9)/L in 2 (4%). Thrombotic neurologic symptoms were the most common (31 patients, 67%), followed by peripheral vascular symptoms (17 patients, 37%); hemorrhagic complications were relatively rare (3 patients, 7%). In most cases, cessation or improvement of clinical manifestations was observed only after further reduction in platelet counts. In conclusion, thrombotic manifestations, including severe ones, are not uncommon in ET at relatively low platelet counts. We recommend that symptomatic patients with relatively low platelet counts be treated and the platelet counts further reduced well into the lower normal range.

Adult↗
PubMed2006

Clinical and laboratory features, pathobiology of platelet-mediated thrombosis and bleeding complications, and the molecular etiology of essential thrombocythemia and polycythemia vera: therapeutic implications.

Microvascular disturbances in essential thrombocythemia (ET) and polycythemia vera (PV), including erythromelalgia, and atypical and typical transient cerebral, ocular, and coronary ischemic attacks, are caused by platelet-mediated transient and occlusive thrombosis in the end-arterial circulation. ET patients with microvascular disturbances have shortened platelet survival, increased beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), and thrombomodulin (TM) levels, and increased urinary thromboxane B2 (TXB2) excretion, indicating platelet-mediated thrombotic processes. Inhibition of platelet cyclooxygenase-1 by aspirin is followed by relief of microvascular disturbances; correction of shortened platelet survival; correction of increased plasma beta-TG, PF4, and TM levels; and correction of increased TXB2 excretion to normal. In PV associated with thrombocythemia, increased hematocrit and whole blood viscosity aggravate the platelet-mediated microvascular syndrome of thrombocythemia to produce major arterial and venous thrombotic complications. Correction of hematocrit to normal by phlebotomy will reduce the major arterial and venous thrombotic complications, but fails to prevent the platelet-mediated microvascular circulation disturbances in PV patients because thrombocythemia persists. Complete relief and prevention of microvascular and major thrombosis in ET and PV patients, in addition to phlebotomy, are obtained by treatment with aspirin and not with coumarin. The discovery of JAK2 V617F gain of function mutation in patients with myeloproliferative disorders (MPDs) expands our insights into the molecular etiology and biological features of ET, PV, and chronic idiopathic myelofibrosis (CIMF). The current concept is that heterozygous JAK2 V617F mutation with increased kinase activity is enough for megakaryocyte proliferation and increased hypersensitive platelets with no or slightly increased erythropoiesis in ET and in early PV mimicking ET. Homozygous JAK2 mutation with pronounced kinase activity is associated with trilinear megakaryocyte, erythroid, and granulocytic myeloproliferation, myeloid metaplasia, and secondary myelofibrosis (MF), with the most frequent clinical picture of classical PV complicated by major thrombosis in addition to the platelet-mediated microvascular thrombotic syndrome of thrombocythemia. The positive predictive value of a JAK2 V617F polymerase chain reaction test for the diagnosis of MPDs is high (near to 100%), but only half of ET and MF (sensitivity 50%) and the majority of PV (sensitivity 85 to 97%) are JAK2 V617F positive. Bone marrow histopathology, when used in combination with specific markers such as serum erythropoietin, PRV-1, endogenous erythroid colony formation, peripheral blood parameters and red cell mass, has a high sensitivity and specificity (near 100%) to detect the early and overt stages of the MPDs and to differentiate between ET, PV, and CIMF in both JAK2 V617F-positive and -negative MPDs.

Blood Platelets↗