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

Thrombolytic therapy has been used fairly extensively in the management of acute proximal deep-vein thrombophlebitis of the extremities, acute pulmonary embolism, and acute peripheral arterial thrombosis and embolism in addition to acute thrombotic coronary events. In the presence of acceptable indications and a favorable benefit to risk ratio, this form of therapy, when successful, has served as a useful adjunct in the management of these disorders. In deep-vein thrombophlebitis, lysis of the thrombus before permanent pathological changes (eg, organization, scarring) have occurred can prevent venous valvular dysfunction and postural venous hypertension and its complications, especially the postphlebitic syndrome. In the more severe forms of acute pulmonary embolism, thrombolytic therapy, when applied early after symptom onset, decreases morbidity and is likely to prevent a chronic increase in pulmonary vascular resistance and persistent pulmonary hypertension. In peripheral arterial thrombo-occlusive events, early restoration of flow through thrombolysis has been shown to limit ischemic damage and serve as a useful supplement to angioplasty or surgery. Thrombolytic therapy has been used less extensively in acute strokes. Here the danger of reperfusion causing bleeding into a softened area of brain undergoing infarction has slowed its evaluation for this disorder; its application to stroke remains experimental.
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PMID:Thrombolytic therapy for noncoronary diseases. 200 69

Thrombolytic therapy offers the promise of major therapeutic intervention in many areas as well as in the treatment of patients with acute myocardial infarction who present to the emergency department. Infusion of tissue-type plasminogen activator (tPA) during field transport has been proven safe, but optimal methods for reliably diagnosing acute myocardial infarction in the prehospital setting have yet to be delineated. A major advance would be achieved if thrombolysis were proven effective in preventing the progression of unstable angina to actual infarction. However, early studies have yielded contradictory results. The use of tPA in dissolving peripheral arterial clots appears very promising, but long-term limb survival has yet to be demonstrated. Unlike heparin, thrombolytic agents can also lyse clot in peripheral deep veins and possibly lessen the tendency toward postphlebitic syndrome. The proper dosage regimen to minimize hemorrhage has not been determined. Pulmonary emboli can be lysed by tPA. IV infusion is as effective as intrapulmonary. Significant complications can be minimized, particularly if major vessel catheterization can be avoided for diagnosis. Even after catheterization for pulmonary angiography, however, thrombolytic therapy appears quite promising. The use of thrombolytic agents for embolic-thrombotic stroke is less promising: therefore, the risk of hemorrhagic complication may not outweigh the potential benefit. Thrombolytic therapy thus offers the potential for significant impact on the practice of emergency medicine.
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PMID:Future role of thrombolytic therapy in emergency medicine. 251 90

Clinical experience with thrombolytics in non-coronary disorders is limited to the plasminogen activators streptokinase, urokinase and alteplase; therapeutic trials with anistreplase (APSAC) are almost, and with saruplase completely, limited to acute myocardial infarction. In terms of thrombus clearance, thrombolytic drugs are superior to heparin in patients with recent deep vein thrombosis in the pelvis or lower limbs. In aggregate, thrombi younger than 8 days are lysed in approximately 60% of patients treated with streptokinase, urokinase or alteplase. The results of studies assessing the subsequent development of the postphlebitic syndrome are conflicting, but most suggest that thrombolytic therapy can reduce symptoms of chronic venous insufficiency. Currently, the combination of systemic thrombolytic drugs followed by heparin is recommended for patients with acute major pulmonary embolism who are haemodynamically unstable. Streptokinase, urokinase and alteplase have all been shown to accelerate the lysis of pulmonary emboli and to decrease pulmonary vascular obstruction and pulmonary hypertension. Systemic venous or intrapulmonary infusions of alteplase offers the same benefit in terms of angiographic and haemodynamic improvement. A short infusion of 100 mg alteplase over 2 hours seems to be superior to a 24-hour infusion of urokinase. None of the thrombolytic trials in pulmonary embolism have been large enough to demonstrate a reduction in mortality. It is now generally accepted that, unless contraindicated, thrombolytic therapy is the front-line treatment for patients with massive pulmonary embolism and major haemodynamic disturbance. The local treatment of acute arterial occlusion in limb arteries results in rapid clearing of the artery in 67% of patients treated with streptokinase; the corresponding success rates for urokinase and alteplase are 81% and 88 to 94%, respectively. The main question appears to be the identification of patients in whom local thrombolysis is the treatment of choice, as opposed to established therapeutic modalities. Thrombolytic treatment following a major ischaemic stroke is hazardous, although clinical improvement has been noted in a minority of patients with recanalised cerebral arteries. The safety and efficacy of thrombolytic treatment remains unproven for this indication, and its use must be restricted to experimental protocols. Thrombolytic treatment in retinal artery or vein occlusion has, in practice, been abandoned.
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PMID:Use of thrombolytic drugs in non-coronary disorders. 268 38

Thrombus formation depends on adherence of blood-formed elements to the intimal surface through platelet-vessel surface interaction, platelet release phenomena and aggregation, formation of fibrin, and the enmeshing of blood cells. Arterial thrombi involve platelet aggregation, whereas venous thrombi found in low flow or during stasis have greater proportions of erythrocytes and fibrin. It is not known if or how abnormalities of flow resistance, platelet thrombus formation, or endothelial and dynamic parameters affect the microcirculation, largely due to the difficulty of obtaining comprehensive data from these systems. Increases of fibrinogen observed in many disorders may result in minor changes in blood viscosity without known physiologic consequence, but in most disorders in which thrombosis is observed, the pathophysiologic mechanisms are multifactorial and abnormal blood viscosity is presumed to be a significant but not limiting component. Therapeutic approaches in thrombotic disorders should recognize which elements of the thrombotic triad predominate. In arterial disorders focus should be on platelet activity, and the objectives of venous thrombosis treatment include prevention of morbidity and death from pulmonary embolism, reduction of morbidity resulting from the acute thrombotic episode, and prevention of the postphlebitic syndrome. Pathology, mechanism, and treatment for specific thrombogenic disorders are described. Treatments suggested for hyperviscosity involve giving antibiotics during crises. Also discussed are thalassemia, paroxysomal nocturnal hemoglobinuria, polycythemia, cryoglobulinemia, paraproteinemia, diabetes mellitus, and disseminated intravascular coagulation. Studies have established a relationship between thromboembolic disease and oral contraceptives (OCs). The risk is only increased while the patient is taking OCs but is compounded in women undergoing surgery or who have a disorder which predisposes to venous disease. The risk for myocardial infarction or stroke is significantly increased when OCs are taken over age 35 and when there is hypertension, smoking, type-II hyperlipoproteinemia, and diabetes mellitus. The risk appears to be a function of estrogen dosage, causing a 25% mean increase in calf venous volume and 30% decrease in vein velocity of venous blood compared to controls. Low flow rates may contribute to venous thromboembolism. OCs may alter precisely regulated systems of coagulation and fibrinolysis and recent studies confirm abnormalities in the hemostatic system attributed to OCs. 16% of women taking OCs have a 60% or greater reduction in antithrombin III activity. The multiple effects of OCs often result in low-grade activation of the hemostatic system, potentially lowering the threshold to precipitate thrombus formation and possibly explaining the increased incidence of thromboembolic disease. Heparin appears to reverse many of these problems.
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PMID:Blood viscosity and thrombosis: clinical considerations. 676 12

A 65-year-old man was referred to our clinic for the rehabilitation of right hemiparesis caused by ischaemic stroke. Hypertension, postphlebitic syndrome of lower limbs, frequent nose bleeding, and anemia were present in his history; in his adolescence, he was treated for idiopathic hypogonadotropic hypogonadism. Further investigations have revealed also microsomia, suggesting a clinical diagnosis of Kallmann syndrome, that is, an association, possible in males and females, of hypogonadotropic hypogonadism with olfactory deficits. A definite diagnosis of hereditary hemorrhagic telangiectasia was made based on clinical criteria and confirmed by genetic analysis.
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PMID:Hypogonadotropic hypogonadism associated with hereditary hemorrhagic telangiectasia [corrected]. 2395 91