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Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study was designed to assess whether factors other than high haemoglobin, thrombocytosis and abnormal platelet function predispose to thrombosis in polycythaemia rubra vera (PRV). Components of the fibrinolytic system and concentrations of the naturally occurring anticoagulants were measured in patients and controls in the resting state; the fibrinolytic capacity was reassessed after venous occlusion. The results were related to presence or absence of a history of thromboembolism. Under resting conditions, patients with PRV had reduced plasminogen activator inhibitor antigen levels and higher fibrin plate lysis area and tissue plasminogen activator activity. Protein C, protein S and factor V levels were reduced. Those patients with a history of thromboembolism had decreased tissue plasminogen activator activity after venous occlusion compared to those who had not experienced a thrombosis. We conclude that reduced fibrinolytic capacity may predispose to thrombosis in PRV. Despite treatment to normalize haemoglobin levels, the patients have persistent activation of their fibrinolytic systems. This, and reduced levels of proteins C and S, may be secondary to a chronic, clinically occult, disseminated intravascular coagulation.
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PMID:The fibrinolytic system and proteins C and S in treated polycythaemia rubra vera. 148 3

The authors report sixteen consecutive cases of erythromelalgia, an infrequent disease in which local heat, redness, and pain develop in the hands and/or feet in recurrent attacks. The disease was essential in nine patients; in the remaining seven, the cause was a myeloproliferative syndrome (polycythemia vera in 3 cases and thrombocythemia in 1 case) or a drug (bromocriptine, nicardipine, and nifedipine, one case each). Acetylsalicylic acid was effective in only six of the nine essential cases. Intravascular platelet activation and aggregation with plugging of the arterioles has been suggested as the mechanism of erythromelalgia in patients with myeloproliferative disorders. Other, as yet unelucidated pathophysiologic events underlie the juvenile-onset forms, which usually fail to respond to acetylsalicylic acid.
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PMID:[Erythromelalgia in adults. Apropos of 16 cases]. 149 72

Erythromelalgia is caused by platelet-mediated acral inflammation and arteriolar thrombosis in thrombocythemia in its primary form or associated with polycythemia vera. The prompt and lasting relief of burning pain by low-dose aspirin is a prerequisite for the diagnosis of thrombocythemic erythromelalgia. Here we extend observations on the occurrence of erythromelalgia in thrombocythemia associated with primary myelofibrosis, Philadelphia-chromosome positive micromegakaryocytic myelofibrosis, and myelodysplastic syndrome type II. It is concluded that erythromelalgia may occur in thrombocythemia of all variants of chronic myeloproliferative disease as well as myelodysplastic syndrome if platelet counts are sufficiently high.
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PMID:Erythromelalgia in thrombocythemia of various myeloproliferative disorders. 834 46

Sixty-three bone marrow (BM) biopsy paraffin sections from patients with platelet counts of 1000 x 10(9)/1 or greater were examined to determine the incidence of megakaryocytic emperipolesis for the various myeloproliferative disorders (MPDs) and for reactive thrombocytosis. Of those cases classified as specific MPDs, 77% of primary thrombocythemia (PT) specimens, 100% of the polycythemia vera (PV) specimens, a single idiopathic myelofibrosis (IMF) specimen, and 17% of the chronic granulocytic leukemia (CGL) specimens demonstrated emperipolesis within megakaryocytes. Two of three cases grouped as MPDs but not further classified also demonstrated emperipolesis. Of the cases of reactive thrombocytosis (RT), 75% showed the presence of emperipolesis. Our results indicate that, with the exception of CGL, emperipolesis can be found in the BM megakaryocytes of the great majority of patients who have extreme thrombocytosis. The underlying cause, whether myeloproliferative or reactive, does not apparently influence the incidence of the phenomenon.
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PMID:The frequency and significance of megakaryocytic emperipolesis in myeloproliferative and reactive states. 163 81

Histologic diagnoses from bone marrow biopsies were analyzed in a total of 1165 patients presenting with thrombocythemic platelet counts at initial examination. Two cut-off points suggested by the Polycythemia Vera Study Group to define thrombocythemia by platelet counts were compared: the former limiting value of 1000 x 10(9)/l platelets versus the recently proposed value of 600 x 10(9)/l. The percentage of all nonproliferative disorders was 41% under the lower, dropping to 11% under the high cut-off point. The respective figures for myeloproliferative disorders increased from 49% under the lower to 74% under the high limiting value. Primary thrombocythemia was included in 72% by the lower, and in only 40% by the high limiting value when classified by its histologic pattern in bone marrow biopsy. A striking decrease of platelet counts occurs, related to fiber increase, among each of three main groups of myeloproliferative disorders: in CML with megakaryocytic predominance from 40% down to 25%, in megakaryocytic-granulocytic myelosis (primary, i.e., agnogenic myelofibrosis) from 36.6% to 10%, and in primary thrombocythemia from 72.6% to 28.6% in cases with reticulin sclerosis.
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PMID:Histologic findings in bone marrow biopsies of patients with thrombocythemic cell counts. 163 84

A 51-year-old woman with no history of prior chemotherapy or radiation therapy was diagnosed with essential thrombocythemia (ET) according to the diagnostic criteria established by the Polycythemia Vera Study Group (PVSG). Cytogenetic analysis of bone marrow metaphases revealed both normal female karyotype and a single clonal abnormality, 46,XX,del(5)(q22q35). While chromosomal abnormalities have been reported in ET, their incidence is very low, and no specific abnormality has been found. Many of the reported cases of ET with chromosomal aberrations, including 5q-, do not meet the diagnostic criteria proposed by the PVSG, and may represent one of the other myeloproliferative disorders or a myelodysplastic syndrome. Furthermore, it is important to distinguish the 5q- syndrome, which may present with thrombocytosis and megakaryocytic hyperplasia, from ET. Our patient appears to be the first example of untreated ET clearly meeting the PVSG criteria in which 5q- was the only clonal abnormality seen at diagnosis.
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PMID:Deletion of the long arm of chromosome 5 in essential thrombocythemia. 833 Feb 75

It has been suggested that the ideal definitive treatment of hemorrhage from esophageal varices due to extrahepatic portal hypertension should be a selective shunt, avoiding splenectomy, when possible, for its unfavorable effects. We present a case with extrahepatic portal hypertension and polycythemia vera who complained acute recurrent variceal bleeding in spite of multiple sclerotherapy sessions, with a massive thrombosis of the portal bed and radicles without any possibility to perform a shunt. The combined treatment was emergency splenectomy followed by a closed program of sclerotherapy. The result was good at two years of follow-up. The optimal treatment of patients with episodes of bleeding varices for extrahepatic portal hypertension and patency of splenic vein should be a selective shunt; poor long-term results have been reported in patients without patency of the major tributaries of the portal system and treated with other operations than shunts. Splenectomy could gave a role in producing these unhappy results. After splenectomy it has been observed an increased thrombocytosis, venous infarction of the bowel, increased susceptibility to infection and also a paradoxical higher risk of bleeding by removing low risk collaterals. From this anecdotal report it can be argued that splenectomy is not necessarily followed by bad results and can be the first therapeutic option in emergency and in some selected cases with huge, high risk varices, difficult to treat by sclerosis only, and without suitable vessel for a shunt.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Splenectomy for hemorrhage from esophageal varices with massive thrombosis of the portal bed in the absence of cirrhosis: an intervention to be reevaluated? Reflections on a clinical case]. 175 98

We report clinical and laboratory findings in a large cohort of patients with thrombocytosis (357 cases). At the time of study, the patients showed a platelet number greater than 500 x 10(9)/L. The follow-up of patients ranged between 3 and 16 years. 123 patients were affected by polycythemia vera (PV), 97 by essential thrombocythemia (ET), 13 by chronic myeloid leukemia (CML) and 31 by myelofibrosis (MF). In 93 subjects, the thrombocytosis was reactive (ST). We found the highest incidence of thrombosis in PV patients, especially concerning the cerebro-vascular system; thrombosis, but in a lower percentage, was recognized in MF patients. Also, ET patients showed a number of thrombosis in peripheral arteries. Thrombosis of the coronary arteries were quite rare while 25% of MPD subjects showed peripheral vein thrombosis. We take into account that many patients showed thrombocytosis associated to one or more atherosclerotic risk factors. Hemorrhages were present especially in CML and in ET, but were not as frequent as thrombosis. The most common bleeding manifestations affected skin and mucosa. Hemorrhages after surgical procedures were also frequent. Gastro-intestinal bleeding was not strictly related to anti-aggregating therapy and occurred not only in PV but also in ET patients.
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PMID:Thrombosis and hemorrhage in thrombocytosis: evaluation of a large cohort of patients (357 cases). 178 83

A 20-year old patient is presented with generalized lymphadenopathy, splenomegaly, hyperleukocytosis and a bone marrow biopsy showing panmyelosis with predominance of immature granulocytes. Lymph node biopsy showed a histopathological feature that was diagnosed as a chronic granulocytic leukemia in blast crisis. The cell surface phenotype of these blast cells showed predominance of immature CD1+, CD7+ T lymphocytes. The T cell lineage was confirmed by DNA rearrangement studies. In addition, the patient showed erythrocytosis, arterial O2 saturation of 92% and thrombocytosis, characteristics of polycythemia vera. After chemotherapy, the patient relapsed with similar symptoms and lymph node cells of similar immature T phenotype. With a revised diagnosis of immature T cell lymphoma associated to a myeloproliferative disorder and polyglobulia, the patient received a combined treatment of Cyclophosphamide-Adriamycin-Vincristine-VM26-Prednisone. Two months later, the patient relapsed again. He received the first phase of induction of the BFM protocol, with partial clinical remission. Five months later, the patient returned with fever, polyadenopathy and splenomegaly. Lymph node cells showed again immature T cell phenotype. The patient was next treated with the m-BACOD scheme, with no response and progression of the disease and he died few days later due to massive bleeding and cardiorespiratory failure.
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PMID:[T lymphoma of immature phenotype associated with polycythemia vera]. 182 May 2

It has been postulated that platelet-derived growth factor and platelet factor 4 (PF4) are involved in the imbalance of the mechanism of medullar stroma maintenance which triggers off the bone marrow myelofibrotic process. In this work we compare the PF4 and the beta-thromboglobulin (beta-TG) and mitogenic activity in platelet-poor plasma (PPP) and platelet extracts (PE) from patients with myeloproliferative disorders (MPD) with those of secondary thrombocytosis (ST) and normal volunteers. Statistically significant differences were found between MPD and ST patients or controls, but none between ST and controls in all the parameters studied. Maximal differences in platelet-derived factors (PDFs) between MPD and control groups were found in polycythemia vera patients. However, the relationship between the presence of myelofibrosis and abnormal levels of beta-TG, PF4 and mitogenic activity in PPP and PE was only observed in patients with agnogenic myeloid metaplasia (AMM). These results show that PDFs are specifically decreased in MPD platelets. Furthermore, no statistical correlation was found between PDFs and the number of platelets. However, other unknown factors or conditions would be necessary to develop myelofibrosis in MPD, which is present in AMM.
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PMID:Abnormal levels of platelet-specific proteins and mitogenic activity in myeloproliferative disease. 138 57


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