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Complications and conversions in myeloproliferative disorders: an analysis of 356 cases.

OBJECTIVE: To investigate the complications and conversions in myeloproliferative disorders (MPD). METHODS: Three hundred and fifty six patients with MPD were reviewed, including 78 with etiologic thrombocythemia (ET), 93 with primary myelofibrosis (MF), 185 with polythythemia vera (PV). The clinical observation, follow-up, analysis with SPSS statistic software were performed. RESULTS: Out of the 356 cases, 101 (28.5%) developed thromboembolic events, 81 (22.8%) hemorrhage, 60 (16.9%) hypertension, 20 (5.6%) coronary heart disease, 3 (0.8%) hemolysis and 1 (0.3%) gastrointestinal ulcer, 2 (0.6%) calculus and 1 (0.3%) bone marrow necrosis. Twenty four patients (6.7%) developed MF (9 in ET, 15 in PV), 2 (0.6%) erythrocytosis (1 in ET, 1 in MF), 3 (0.8%) thrombocythemia (all in PV), 5 (1.4%) acute leukemia (2 in ET, 3 in MF) and 1 (0.3%) multiple myeloma (in ET). Eleven cases (3.1%) died, 5 (1.4%) from acute leukemia, 2 (0.6%) fatal hemorrhages, 1 (0.3%) each myocardial infarction and infectious shock, 2 (0.6%) unknown causes. CONCLUSION: Embolism and bleeding were the main complications in MPD. Conversions among ET, MF and PV hematological malignancies could occur.

Adolescent↗

Treatment indications and choice of a platelet-lowering agent in essential thrombocythemia.

The therapeutic strategy in patients with essential thrombocythemia (ET) is a difficult balance between the prevention of bleeding and thrombotic complications and the risks of drug side effects and toxicity. Major bleeding is rare and seems to be related to higher platelet counts. Therefore, a platelet count greater than 1500 x 10(9)/L is generally regarded as an indication for cytoreduction. Thrombotic complications include microvascular occlusive symptoms, which are usually reversible with low-dose aspirin, and large vessel thrombosis. The risk of major thrombosis is higher in patients with ET who are older than 60 years and who have had a previous occlusive event. In this high-risk group, the nonalkylating agent hydroxyurea significantly reduces the rate of vascular complications and has emerged as the treatment of choice. However, the long-term risk:benefit ratio of hydroxyurea remains disputed because its leukemogenic potential has not been ruled out. This holds also for other myelosuppressive agents such as busulfan and pipobroman. Other drugs of particular interest for young patients include recombinant interferon-alpha and anagrelide. Both of these drugs are effective in lowering platelet counts, but their efficacy in reducing clinical complications remains to be demonstrated. Furthermore, interferon and anagrelide have frequent and clinically important side effects. Thus, further clinical studies are required to establish their role in the management of patients with ET.

Alkylating Agents↗

[Occupational and environmental risk factors for essential thrombocythemia: a case-control study].

BACKGROUND: Essential Thrombocythemia (ET) is a chronic myeloproliferative disorder characterized by a long median survival, even though serious complications such as acute hemorrhagic or thrombotic events are not infrequent. Very few information are available about risk factors for ET because of lack of epidemiological studies focused on this topic. METHODS: We conducted a case-control study in order to analyze the possible association between ET and some occupational and environmental risk factors. A total of 93 patients enrolled in two hospitals in Turin (Italy) and 280 subjects randomly selected from the general population as controls, were included in the analysis. RESULTS: We found an association between ET and selected occupations. OR estimates suggest a significant association between ET cooks/waiters (OR 4.96, CI 1.59-16.9) and clerks (OR 2.63, CI 1.53-4.51) and a non significant association between ET and hairdressers (OR 5.10, CI 0.82-31.4), nurses (OR 3.75, CI 0.80-19.4), farmers (OR 1.74, CI 0.84-3.56), electricians (OR 1.42, CI 0.48-3.78), and photographers (OR infinity). Data did not suggest any strong association between environmental risk factors and ET. CONCLUSIONS: Selected occupations seem to be associated to ET. The association of ET with occupations as hairdressers, farmers and electricians could be attributable to known risk factors for other hematolymphopoietic malignancies such as hair dye, pesticides and magnetic fields. The association with other occupations is more difficult to explain, but all the results we presented are consistent with data from previous studies on onco-hematological diseases.

Adult↗

Clinical implications of elevated PAI-1 revisited: multiple arterial thrombosis in a patient with essential thrombocythemia and elevated plasminogen activator inhibitor-1 (PAI-1) levels: a case report and review of the literature.

Plasminogen activator inhibitor (PAI-1), a member of the serine protein family, is the most active in vivo inhibitor of fibrinolysis induced by plasminogen, tissue plasminogen activator (tPA), and urokinase type plasminogen activator (uPA). While the association between elevated PAI-1 and thrombogenesis has been well studied for several disease processes, including coronary disease, postoperative deep vein thrombosis (DVT), myocardial infarction, malignancy, and diabetes, few studies have concentrated on the correlation between elevated PAI-1 levels and thrombogenesis in patients with myeloproliferative disorders. Essential thrombocythemia (ET), a chronic myeloproliferative disorder, characterized by the overproduction of poorly functioning platelets, is associated with both thrombotic and hemorrhagic life-threatening complications. Although the events resulting in thrombogenesis in such patients may be multifactorial in nature, an association between elevated PAI-1 levels and thrombus formation has been proposed. Herein we present a patient diagnosed with ET complicated by multiple episodes of arterial thrombosis. Elevations in PAI-1 levels were documented repeatedly. The role of elevated PAI-1 when associated with other disease processes is also discussed.

Blood Coagulation↗

Chronic myeloproliferative diseases with an elevated platelet count (in excess of 1,000,000/microliter): a clinicopathological study on 46 patients with special emphasis on primary (essential) thrombocythemia.

A clinicopathological study was performed on 46 patients with chronic myeloproliferative diseases (CMPD) showing a thrombocythemia in excess of 1,000 x 10(9)/liter. When applying rigid diagnostic criteria only 23 patients were compatible with the initially suspected diagnosis of primary thrombocythemia (PTH). Comparison of PTH with the other entities of CMPD (CGL, 10, AMM, 6, and polycythemia, 7 cases) revealed a sustained elevation of the platelet count observable over a period of 2 to 8 years, no marked leukocytosis or abnormalities of the differential blood count, and a normal score of the leukocyte alkaline phosphatase. Episodes of hemorrhage and thrombosis as well as neurological symptoms (paresthesias, dizziness, headache), were encountered frequently as clinical manifestations in PTH. Survival time in PTH was significantly longer than in CGL with accompanying thrombocythemia. In a consecutively biopsied population of patients with CMPD, incidence of PTH was about 8%. In PTH the characteristic histopathology of the bone marrow consisted of an isolated (monolinear) proliferation of the megakaryocytes (density 127 +/- 47/mm2) without gross abnormalities of this cell lineage or a conspicuous increase in neutrophilic granulo- or erythrocytopoiesis. These lesions are significantly different from the morphological findings in the other CMPD with extreme thrombocytosis.

Actuarial Analysis↗

Thrombocytosis and thrombocythemia.

Elevated platelet counts may be encountered as a reactive phenomenon secondary to a variety of systemic conditions (thrombocytosis) or may represent a primary disorder of the bone marrow (thrombocythemia). The diagnosis of essential thrombocythemia is difficult and relies on exclusion of other myeloproliferative states and nonhematologic illnesses associated with increased platelet number. The paradoxic clinical complications of hemorrhage and thrombosis, the presence of splenomegaly, and the finding of various qualitative platelet abnormalities point to existence of the neoplastic disorder. Although treatment of the symptomatic patient with platelet lowering agents or antiplatelet drugs may be indicated and effective, the role of therapy in the asymptomatic individual remains highly controversial.

Adolescent↗

Pure red cell aplasia associated with essential thrombocythemia (a case report).

A rare case of erythroblastopenia associated with essential thrombocythemia (ET) is described. The patient had markedly elevated platelet count (5200 x 10(9)/1) and significant platelet dysfunction leading to extensive soft tissue and gastrointestinal hemorrhage. There was paucity of erythroid precursors in the bone marrow - a feature hitherto undescribed in ET. The thrombocytosis responded to well busulphan therapy but patient succumbed to fulminant infection consequent upon drug induced neutropenia.

Female↗

Essential thrombocythemia.

Significant progress in our understanding of the molecular pathogenesis of essential thrombocythemia (ET) and the other Philadelphia (Ph) chromosome-negative myeloproliferative disorders (MPDs) has recently been achieved. Unfortunately, the diagnosis of ET still relies on a set of exclusion criteria developed years ago, as recent advances have yet to be evaluated for this purpose. The clinical course of ET is characterized by an increased incidence of thrombotic and hemorrhagic complications and an inherent tendency to progress into myelofibrosis or acute myeloid leukemia (AML). There is concern about undesirable effects of cytoreductive therapy given to prevent vascular events, particularly the risk of accelerating the rate of hematologic transformation. Thus, management involves modification of reversible vascular risk factors and further stratification according to the thrombotic risk. Myelosuppressive agents are not recommended in low-risk patients, whereas controlled studies support the therapeutic value of hydroxyurea (HU) plus aspirin in high-risk cases. Anagrelide or interferon-alpha (IFN-alpha) could be considered as second-line therapy in patients refractory or intolerant of HU. IFN-alpha is preferred in pregnant women.

Adult↗

MCNU in the treatment of essential thrombocythemia--a pilot study.

The efficacy of a single dose of MCNU 150 mg was evaluated in nine symptomatic patients with essential thrombocythemia (ET). As the platelet counts increased during the following 4 weeks, an extra dose of 100 mg of MCNU was administered to three patients. All patients had thrombotic or hemorrhagic complications. Seven patients responded. The mean platelet count decreased to below 1.0 x 10(12)/l within 5 weeks; it reached its lowest level (0.35 x 10(12)/l) at 6 weeks and became stable at less than 1.0 x 10(12)/l without further therapy for 12 weeks in all patients. Thrombotic and hemorrhagic complications ameliorated within 4 weeks in all patients. Our study indicates that MCNU acts as a platelet-reducing agent in patients with ET.

Adult↗

Essential thrombocythemia.

Essential thrombocythemia (ET) is an acquired myeloproliferative disorder (MPD) characterized by a sustained elevation of platelet number with a tendency for thrombosis and hemorrhage. The prevalence in the general population is approximately 30/100,000. The median age at diagnosis is 65 to 70 years, but the disease may occur at any age. The female to male ratio is about 2:1. The clinical picture is dominated by a predisposition to vascular occlusive events (involving the cerebrovascular, coronary and peripheral circulation) and hemorrhages. Some patients with ET are asymptomatic, others may experience vasomotor (headaches, visual disturbances, lightheadedness, atypical chest pain, distal paresthesias, erythromelalgia), thrombotic, or hemorrhagic disturbances. Arterial and venous thromboses, as well as platelet-mediated transient occlusions of the microcirculation and bleeding, represent the main risks for ET patients. Thromboses of large arteries represent a major cause of mortality associated with ET or can induce severe neurological, cardiac or peripheral artery manifestations. Acute leukemia or myelodysplasia represent only rare and frequently later-onset events. The molecular pathogenesis of ET, which leads to the overproduction of mature blood cells, is similar to that found in other clonal MPDs such as chronic myeloid leukemia, polycythemia vera and myelofibrosis with myeloid metaplasia of the spleen. Polycythemia vera, myelofibrosis with myeloid metaplasia of the spleen and ET are generally associated under the common denomination of Philadelphia (Ph)-negative MPDs. Despite the recent identification of the JAK2 V617F mutation in a subset of patients with Ph-negative MPDs, the detailed pathogenetic mechanism is still a matter of discussion. Therapeutic interventions in ET are limited to decisions concerning the introduction of anti-aggregation therapy and/or starting platelet cytoreduction. The therapeutic value of hydroxycarbamide and aspirin in high risk patients has been supported by controlled studies. Avoiding thromboreduction or opting for anagrelide to postpone the long-term side effects of hydrocarbamide in young or low risk patients represent alternative options. Life expectancy is almost normal and similar to that of a healthy population matched by age and sex.

Adult↗

Myeloproliferative disorders: complications, survival and causes of death.

This retrospective single-center study compared thromboembolic and hemorrhagic complications, survival and causes of death in a cohort of 102 consecutive patients with myeloproliferative disorders (MPD). We included 17 patients with essential thrombocythemia (ET), 59 with polycythemia vera (PV), and 26 with osteomyelofibrosis (OMF). The median follow-up was 3.7 years. Estimated 8-year probability of complications for the entire cohort was 80 +/- 11% (95% confidence interval), without significant differences among MPD subgroups. The rate of thromboembolic complications, expressed as the number of events per 100 patient years, was 16.7 for patients with PV, 13.8 for OMF, and 7.5 for ET. Fifty-four percent of thromboembolic events in PV involved cerebral or limb arteries. The rate of bleeding complications was highest in patients with OMF (31.8 per 100 patient years), followed by ET and PV (11.8). Ninety percent of bleeding episodes affected the skin. mucosal membranes, and the gastrointestinal tract. Eight-year survival was highest in ET with 91 +/- 17%, followed by PV (66 +/- 18%) and OMF (40 +/- 31%) (P< 0.01). Twenty-four patients died during the observation period, and fatal thrombosis (in five patients) represented the leading cause of death. Only two patients with MPD died from fatal hemorrhage and one from acute leukemia. We conclude that survival is highest in ET and lowest in OMF. Both thromboembolic and hemorrhagic complications are frequent. However, thrombosis appears to be more often fatal than bleeding complications. Prophylaxis of thromboembolic events remains a key issue in the management of MPD.

Adolescent↗

Familial essential thrombocythemia: clinical characteristics of 11 cases in one family.

Reports on familial occurrence of essential thrombocythemia (ET) are scanty. Many clinical and hematological aspects of familial ET have not been clarified yet. We studied 16 family members in four successive generations. By laboratory tests and bone marrow examination they were divided into a non-thrombocythemia group (n = 5) and into ET patients (n = 11). Five ET patients were asymptomatic, three patients had both vaso-occlusive and hemorrhagic symptoms, and three patients only vaso-occlusive symptoms. The platelet count ranged from 500 to 1700 x 10(9)/l. Symptoms correlated with age but not with platelet count. ADP-induced platelet aggregation distinguished best between patients and non-ET subjects. Four patients and four non-ET subjects had factor VIII:C or von Willebrand factor antigen abnormalities; all but one had blood group O. These abnormalities were not due to inherited von Willebrand's disease according to haplotype analysis. Two patients and three non-ET subjects had a bleeding diathesis. One of these two patients and all three non-ET subjects had a decreased factor VIII:C or vWF:Ag. No chromosome abnormalities were found. In conclusion, familial ET has a relatively benign course with clinical manifestations similar to nonfamilial cases, and it is probably transmitted by an autosomal dominant mode of inheritance.

Adolescent↗

Update on diagnosis and management of essential thrombocythemia.

Patients with essential thrombocythemia carry a high risk for thromboembolic and bleeding events but they have an almost normal life expectancy. A careful evaluation of the medical history and an exact diagnosis is mandatory to estimate each patient's risk for morbidity and to choose the most appropriate treatment measure. In patients with the need of cytoreductive therapy, the benefits of therapy have to outweigh the potential risks of drug toxicities. Hydroxyurea is the most useful cytoreductive drug for elderly patients; in younger persons, interferon alpha or anagrelide may be the drugs of choice. The combination of anagrelide with acetylsalicylic acid may be contraindicated in patients with a history of bleeding.

Age Factors↗