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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The presenting features, haematological and clinical course of 30 patients with unexplained high venous haematocrit have been analysed. At presentation these patients had definite polycythaemia, but lacked other features which would permit their classification as primary proliferative polycythaemia (PPP). In the follow-up period, twelve patients (40%) developed features within 6 years of diagnosis which allowed them to be reclassified as PPP. It is suggested that, because of this transition, the term idiopathic erythrocytosis is a more suitable initial description of this group than, for example, benign erythrocytosis. The high incidence of vascular complications at presentation, and the fact that a cerebrovascular accident was responsible for the death of five out of the seven patients who have so far died, is discussed and compared with similar events in PPP. The existence of a pure line red cell proliferation cannot be confirmed or excluded by the observations in the present group of patients. The findings do indicate that follow-up and observation of such patients may establish causes for polycythaemia not in evidence or considered at presentation.
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PMID:The course and complications of idiopathic erythrocytosis. 53 13

To date, there is little information available on stroke risk factors in a major ethnic minority such as Mexican-Americans (M-A) in the USA. Forty-three M-A patients were admitted to The Methodist Hospital and Ben Taub General Hospital (Houston) for a 12-month period, with diagnosis of atherosclerotic stroke. Thrombosis was diagnosed in 31 patients (72%), embolism from atherosclerotic sources in seven (16.4%), and parenchymal hemorrhage in five (11.6%). Hypertension was a common risk factor in all groups, being higher in hemorrhage followed by thrombosis and embolism. Arteriosclerotic heart disease was a common risk to all stroke types. TIAs, hyperlipidemia, diabetes, associated atherosclerotic lesions, smoking, obesity, erythrocytosis and sedentary life were significantly associated with embolism; less so with thrombosis or hemorrhage. Gout was only associated with thrombosis. These results indicate similar risk factors for Anglo-saxons and M-A in the USA with some minor differences between the Mexican and the USA stroke series.
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PMID:Risk factors in stroke in a Mexican-American population (Houston). 61 32

The importance of fibrinogen has been identified in two prospective observational studies. Reactive elevations in fibrinogen levels that occur within hours of a major stroke invalidate most cross-sectional case-control studies evaluating fibrinogen as a risk factor. However, as no elevation is seen following fresh episodes of transient ischaemic attacks, reliable conclusions drawn from a case-control study using such patients support the findings of the prospective studies. The association is related to occlusive stroke, but the relationship with intracerebral haemorrhage is unclear. The relationship has been found to be independent of other haemostatic and haemorheological factors (e.g. von Willebrand factor, tissue plasminogen activator and packed cell volume). Adjustment for regression dilution bias would further strengthen the observed relationship. Therefore, after blood pressure, fibrinogen is the most important potentially treatable risk factor for ischaemic stroke. There are several mechanisms whereby fibrinogen could promote athero-thromboembolism: thrombosis through a hypercoagulable state; the acceleration of atherosclerosis; or the reduction of blood flow due to high blood or plasma viscosity. The mechanism, however, is unlikely to be mediated through high blood viscosity per se as secondary erythrocytosis (another major determinant of blood viscosity) has not consistently been found to be a risk factor for stroke. Studies relating fibrinogen levels to the degree of carotid artery stenosis support the accelerating influence of fibrinogen on atherosclerosis. Fibrinogen should be considered a risk factor for ischaemic stroke and included in the assessment of individual risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fibrinogen and cerebrovascular disease. 779 30

An 85-year-old woman had a right-sided renal cell carcinoma removed 20 years ago. At haemoglobin concentration. Two years ago she had a syncope, at which time the haemoglobin concentration was 16.9 g/dl. Ultrasound and computed tomography (CT) revealed an extensive retroperitoneal space-occupying lesion, which however was not investigated further, and no therapeutic consequences were drawn. An erythrocytosis (7.5 x 10(6)/microliters) and elevated haemoglobin concentration (> 20 g/dl) were found when she was examined after a fall in which she had sustained only minimal injury. The retroperitoneal mass had slightly increased in size. Histological examination of a CT-guided fine-needle biopsy revealed metastases of the hypernephroid carcinoma. The serum erythropoietin concentration was increased (42.4 U/l) and failed to increase even after repeated venesections, indicating erythropoietin production by the late metastases of the renal cell carcinoma. There was no evidence for any systemic haematological disease. Six months after the diagnosis of metastases the patient died at home, presumably of a cerebrovascular accident.
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PMID:[Polycythemia in the late metastasis of an erythropoietin-producing renal-cell carcinoma]. 818 21

Therapeutic erythrocytapheresis (TEA) has been used in different diseases such as polycythemia vera (PV), secondary erythrocytosis or hemochromatosis as a process of the less cumbersome but more expensive phlebotomy. TEA is preferred in emergency conditions such as thrombocytosis or in conditions such as porphyria cutanea tarda (PCT) or erythropoietic porphyria when plasma exchange (PEX) is often combined with TEA to reduce extracellular levels of uroporphyrin which contribute to plasma hyperviscosity. TEA is often combined with drug therapy that varies from etoposide in PV to EPO and desferoxamine which are used to mobilize and reduce iron stores in hemochromatosis. Benefits from this combination may be more long lasting than expected. Nonetheless for TEA, there is no standard protocol and, clinical experience with this therapy remains highly anecdotal. Therapeutic red cell-exchange (TREX) has been used with much interest over the years, starting with the management of hemolytic disease of the newborn and later used to correct severe anemia in thalassemia patients thereby preventing iron overload. It has also been used for the management of complications of sickle cell disease such as priapism, chest syndrome, stroke, retinal, bone, splenic and hepatic infarction or in preparation for surgery by reducing HbS to less than 30%. Automated apheresis has also favored the use of TREX in conditions such as paroxysmal nocturnal hemoglobinuria and aniline poisoning, arsenic poisoning, Na chlorate intoxications and CO intoxications, hemoglobinopathies, autoimmune hemolytic anemia, reactions due to ABO incompatibility, in preparation for ABO incompatible bone marrow transplantation or for preventing anti-D immunization after the transfusion of D(+) cells to D(-) recipients. Another field of application has been in the emergency management of intraerythrocytic parasite infections such as malaria and babesiosis. Application of TREX may be wide but its real use remains limited. In our personal experience, in 16 years, only 167 TREX procedures have been carried out in a total of 13,747 therapeutic procedures. This represents only 1.21% of the total.
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PMID:Clinical application of therapeutic erythrocytapheresis (TEA). 1083 21

The aim of this review is to present the current knowledge regarding stroke. It will appear in three parts (in part II the pathogenesis, investigations, and prognosis will be presented, while part III will consist of the management and rehabilitation). In the current part (I) the definitions of the clinical picture are presented. These include: amaurosis fugax, vertebrobasilar transient ischemic attack, and stroke (with good recovery, in evolution and complete). The role of the following risk factors is discussed in detail: age, gender, ethnicity, heredity, hypertension, cigarette smoking, hyperlipidemia, diabetes mellitus, obesity, fibrinogen and clotting factors, oral contraceptives, erythrocytosis and hematocrit level, prior cerebrovascular and other diseases, physical inactivity, diet and alcohol consumption, illicit drug use, and genetic predisposition. In particular, regarding the carotid arteries, the following characteristics are analyzed: atheroma, carotid plaque echomorphology, carotid stenosis, presence of ulcer, local variations in surface deformability, pathological characteristics, and dissection. Finally the significance of the cerebral collateral circulation and the conditions predisposing to cardioembolism and to cerebral hemorrhage are presented.
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PMID:Stroke: epidemiology, clinical picture, and risk factors--Part I of III. 1110 23

The Philadelphia chromosome-negative chronic myeloproliferative disorders (CMPD), polycythemia vera (PV), essential thrombocythemia (ET) and chronic idiopathic myelofibrosis (IMF), have overlapping clinical features but exhibit different natural histories and different therapeutic requirements. Phenotypic mimicry amongst these disorders and between them and nonclonal hematopoietic disorders, lack of clonal diagnostic markers, lack of understanding of their molecular basis and paucity of controlled, prospective therapeutic trials have made the diagnosis and management of PV, ET and IMF difficult. In Section I, Dr. Jerry Spivak introduces current clinical controversies involving the CMPD, in particular the diagnostic challenges. Two new molecular assays may prove useful in the diagnosis and classification of CMPD. In 2000, the overexpression in PV granulocytes of the mRNA for the neutrophil antigen NBI/CD177, a member of the uPAR/Ly6/CD59 family of plasma membrane proteins, was documented. Overexpression of PRV-1 mRNA appeared to be specific for PV since it was not observed in secondary erythrocytosis. At this time, it appears that overexpression of granulocyte PRV-1 in the presence of an elevated red cell mass supports a diagnosis of PV; absence of PRV-1 expression, however, should not be grounds for excluding PV as a diagnostic possibility. Impaired expression of Mpl, the receptor for thrombopoietin, in platelets and megakaryocytes has been first described in PV, but it has also been observed in some patients with ET and IMF. The biologic basis appears to be either alternative splicing of Mpl mRNA or a single nucleotide polymorphism, both of which involve Mpl exon 2 and both of which lead to impaired posttranslational glycosylation and a dominant negative effect on normal Mpl expression. To date, no Mpl DNA structural abnormality or mutation has been identified in PV, ET or IMF. In Section II, Dr. Tiziano Barbui reviews the best clinical evidence for treatment strategy design in PV and ET. Current recommendations for cytoreductive therapy in PV are still largely similar to those at the end of the PVSG era. Phlebotomy to reduce the red cell mass and keep it at a safe level (hematocrit < 45%) remains the cornerstone of treatment. Venesection is an effective and safe therapy and previous concerns about potential side effects, including severe iron deficiency and an increased tendency to thrombosis or myelofibrosis, were erroneous. Many patients require no other therapy for many years. For others, however, poor compliance to phlebotomy or progressive myeloproliferation, as indicated by increasing splenomegaly or very high leukocyte or platelet counts, may call for the introduction of cytoreductive drugs. In ET, the therapeutic trade-off between reducing thrombotic events and increasing the risk of leukemia with the use of cytoreductive drugs should be approached by patient risk stratification. Thrombotic deaths seem very rare in low-risk ET subjects and there are no data indicating that fatalities can be prevented by starting cytoreductive drugs early. Therefore, withholding chemotherapy might be justifiable in young, asymptomatic ET patients with a platelet count below 1500000/mm(3) and with no additional risk factors for thrombosis. If cardiovascular risk factors together with ET are identified (smoking, obesity, hypertension, hyperlipidemia) it is wise to consider platelet-lowering agents on an individual basis. In Section III, Dr. Gianni Tognoni discusses the role of aspirin therapy in PV based on the recently completed European Collaboration on Low-dose Aspirin in Polycythemia Vera (ECLAP) Study, a multi-country, multicenter project aimed at describing the natural history of PV as well as the efficacy of low-dose aspirin. Aspirin treatment lowered the risk of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke (relative risk 0.41 [95% CI 0.15-1.15], P =.0912). Total and cardiovascular mortality were also reduced by 46% and 59%, respectively. Major bleedings were slightly increased nonsignificnsignificantly by aspirin (relative risk 1.62, 95% CI 0.27-9.71). In Section IV, Dr. Giovanni Barosi reviews our current understanding of the pathophysiology of IMF and, in particular, the contributions of anomalous megakaryocyte proliferation, neoangiogenesis and abnormal CD34(+) stem cell trafficking to disease pathogenesis. The role of newer therapies, such as low-conditioning stem cell transplantation and thalidomide, is discussed in the context of a general treatment strategy for IMF. The results of a Phase II trial of low-dose thalidomide as a single agent in 63 patients with myelofibrosis with meloid metaplasia (MMM) using a dose-escalation design and an overall low dose of the drug (The European Collaboration on MMM) will be presented. Considering only patients who completed 4 weeks of treatment, 31% had a response: this was mostly due to a beneficial effect of thalidomide on patients with transfusion dependent anemia, 39% of whom abolished transfusions, patients with moderate to severe thrombocytopenia, 28% of whom increased their platelet count by more than 50 x 10(9)/L, and patients with the largest splenomegalies, 42% of whom reduced spleen size of more than 2 cm.
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PMID:Chronic myeloproliferative disorders. 1463 83

Complications of chronic hypoxia, including erythrocytosis, hyperviscosity, abnormalities of hemostasis, cerebral abscesses, stroke, and endocarditis, are among the most common consequences of cyanotic heart disease in adults. The compensatory erythrocytosis of cyanotic heart disease can become pathologic by causing an increase in blood viscosity, thereby decreasing perfusion and resulting in decreased total oxygen delivery and increased risk of venoocclusive/hyperviscosity syndrome. Treatment of hyperviscosity secondary to erythrocytosis in cyanotic heart disease is controversial. Data is limited but suggest that phlebotomy has the potential to increase exercise capacity, reduce the symptoms of hyperviscosity, and reduce the potential risk of vasoocclusive disease in selected patients with polycythemia secondary to cyanotic heart disease. Unfortunately, repeated phlebotomy can quickly lead to iron deficiency, resulting in microcytic erythrocytes that induce higher viscosity than normocytic erythrocytes, which may increase the risk for venoocclusive events. There are limited data on the use of hydroxyurea to suppress erythrocytosis in this patient population. The authors conclude that until newer approaches to decreasing hematocrit without inducing iron deficiency are shown to be safe and efficacious, phlebotomy should only be used for the acute resolution of hyperviscosity symptoms. In addition, the use of hydroxyurea should be limited to patients with recurrent symptoms.
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PMID:Blood is thicker than water: the management of hyperviscosity in adults with cyanotic heart disease. 1717 81

Secondary erythrocytosis in cyanotic congenital heart disease (CCHD) causes substantial morbidity because of complications of hyperviscosity, including stroke and chronic end organ damage. Phlebotomy provides temporary improvement but leads to iron deficiency and can actually increase blood viscosity. We describe the successful use of hydroxyurea (hydroxycarbamide) in four patients with uncorrected CCHD and symptomatic secondary erythrocytosis. In all patients, hydroxyurea improved symptoms of hyperviscosity. Substantial decreases in the red blood cell (RBC) count were observed, along with increases in the mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH), leading to only modest declines in the circulating hemoglobin concentration. Two patients experienced transient mild myelosuppression, which promptly resolved with dose reduction of hydroxyurea. Hydroyxurea provides a novel and useful therapeutic approach to reduce hyperviscosity from secondary erythrocytosis in patients with CCHD, while preserving oxygen carrying capacity and avoiding iron depletion by phlebotomy.
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PMID:Hydroxyurea therapy for management of secondary erythrocytosis in cyanotic congenital heart disease. 1750 64

Secondary erythrocytosis of cyanotic congenital heart disease (CCHD) is pathologically different from primary erythrocytosis of polycythemia vera (PV). An association between elevated hematocrit and thrombosis has been established in PV patients, and treatment guidelines recommend maintaining hematocrit <45%. Although an association between elevated hematocrit and thrombosis has not been established in CCHD and secondary erythrocytosis, the current clinical practice is to phlebotomize these patients to hematocrit <65%. We report a 21-year-old woman with CCHD who presented with symptomatic erythrocytosis with numbness and tingling with hemoglobin 25.2 g/dl and hematocrit 75.8%. Her symptoms resolved with IV hydration. Other factors, including dehydration and iron deficiency, may precipitate hyperviscosity symptoms. The treatment is volume replacement and low-dose iron therapy, not phlebotomy. Repeated phlebotomy causes iron deficiency with microcytic erythrocytes, which increases the whole blood viscosity and, therefore, can potentially accentuate rather than decrease the risk for a cerebrovascular accident.
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PMID:Cyanotic congenital heart disease (CCHD) with symptomatic erythrocytosis. 1791 83


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