Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies of the pulmonary circulation in normal man, performed with external radiation detectors, have shown that pulmonary blood volume is about 10% of total blood volume. Pulmonary blood volume was unchanged in patients with acute or chronic left atrial hypertension and in normal persons during expansion of total blood volume in spite of marked increases in pulmonary vascular pressures. However, pulmonary blood volume was greatly increased in patients with polycythemia rubra vera and a large total blood volume and in patients with a left to right shunt but normal pulmonary intravascular pressure. Studies of regional myocardial perfusion with injection of xenon-133 solution into the left coronary artery revealed localized areas of ischemia distal to stenotic lesions even when the patient was at rest. During angina produced by pacing, more severe ischemia occurred, thus suggesting that functional factors reduce local perfusion below resting levels. In patients with "variant" angina, intravenous injection of thallium-201 chloride during spontaneous attacks has revealed large cold areas in myocardial scintigrams not present under control conditions, thus suggesting severe transmural reduction of perfusion in heart muscle corresponding to S-T segment elevation in the electrocardiogram.
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PMID:Pathophysiologic studies of the pulmonary and coronary circulations in man. 99 14

Over a seven year period 52 patients having a clinical diagnosis of spontaneous peripheral arterial microembolization were identified. Sixty-one percent of patients were female, 15% were diabetic, and 73% used tobacco chronically. A striking finding was the very high incidence of associated systemic disorders such as thrombocytosis (8), polycythemia vera (3), metastatic adenocarcinoma (3), or collagen disease requiring steroid therapy (4). Forty-nine patients had significant proximal arterial lesions as the origin of their emboli. Three patients had digital ischemia as a result of increased platelet aggregation without arterial obstruction. Forty-eight patients underwent surgical therapy. Operative mortality was 4% and overall limb salvage in survivors was 96%. The clinical syndrome of arterial microembolization may result from several pathophysiologic mechanisms including cholesterol embolization from ulcerated plaques, fibrino-platelet aggregation in patients with hematologic disorders, or dislodgement of mural thrombus in those with aneurysmal disease. We observed aortoiliac disease to be more frequent than femoral-popliteal disease, and both were amenable to surgical correction. We conclude that the genesis of arterial microembolization is multifactorial and that a variety of systemic diseases may work in concert with atherosclerotic arterial disease to produce this clinical syndrome. Prompt recognition and appropriate treatment of this disorder can yield high rates of limb salvage.
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PMID:Spontaneous peripheral arterial microembolization. 139 20

We report a case of erythrocytosis in a patient with end-stage renal failure on chronic hemodialysis. The patient with polycystic kidney disease had an average Hb level of 10 g/dl while on hemodialysis for 3 years. He developed erythrocytosis (Hb 17.6 g/dl) following a cadaveric renal transplantation. No signs suggesting polycythemia vera were found. Nonrenal causes of secondary erythrocytosis such as anoxia, hemoglobinopathies or tumors were excluded. Angiography showed renal artery occlusion of the native kidney. Serum erythropoietin level was 85 U/l (normal 52 +/- 31 U/l) as measured by 3H-thymidine uptake. It is suggested that ischemia caused by the renal artery thrombosis stimulated the erythropoietin production in the native polycystic kidney.
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PMID:Erythrocytosis associated with renal artery thrombosis in a patient with polycystic kidney disease on hemodialysis. 211 27

More than a dozen primary hematologic disorders have been associated with ischemic stroke. Inherited deficiencies of antithrombin III, protein C, and protein S have been linked with stroke in case reports; optimal screening requires functional as well as antigenic assays. Antiphospholipid antibodies and lupus anticoagulants are the most frequently identified acquired states associated with ischemic stroke. Polycythemia vera, sickle cell anemia, sickle-C disease, and essential thrombocythemia are the major disorders of formed blood elements causing stroke. Special, step-wise screening for occult prothrombotic entities in stroke patients is recommended for young persons with stroke of uncertain cause, for those with prior venous thrombosis, for those with a family history of unusual thrombosis, and for those with no other explanation for recurrent stroke. Acquired, perhaps transient, abnormalities of platelets, coagulation inhibition, and fibrinolysis may contribute importantly to brain ischemia in synergy with other mechanisms, but at present these remain ill-defined. The contribution of prothrombotic diatheses to stroke is probably underrecognized and warrants further investigation.
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PMID:Hematologic disorders and ischemic stroke. A selective review. 186 63

The absolute polycythaemias include all patients who have a raised red cell mass. They may be divided by clinical and laboratory investigation into: primary proliferative polycythaemia (polycythaemia rubra vera), secondary polycythaemias, and idiopathic erythrocytosis. In vitro, the PCV is the single most important determinant of whole blood viscosity with the most marked effects at low shear rates. Yield stress is also dominantly influenced by PCV. Thus in the absolute polycythaemias, from whatever cause, whole blood viscosity and yield stress are high. However, flow conditions in vivo are much more complex than those usually used in in-vitro measurements. Under normal physiological conditions, whole blood viscosity probably does not determine flow in vivo. The observed in-vitro changes are only of relevance in vivo when local or general abnormalities of flow occur. In primary proliferative polycythaemia (PPP) and idiopathic erythrocytosis, presentation with ischaemia or thrombosis (either arterial or venous) is common, and the cerebral circulation is at particular risk. The incidence of vascular occlusion is positively correlated with the PCV. There is an inverse correlation between PCV and cerebral blood flow (CBF), with untreated patients having low CBF values. This is probably a 'physiological' change related to the increased oxygen carrying capacity at high PCV values. However, in many patients, cerebral oxygen carriage actually increases on reduction of the PCV to normal. This explains the improvement in cerebral ischaemic symptoms and mental performance which may be observed following treatment. Platelet contact and adhesion to the vessel wall are increased at high PCV values and, combined with the lower blood flow in both the arteries and veins, tend to favour thrombus formation. Ischaemia causes vessel dilatation but when this is maximal the high whole-blood viscosity demonstrated in vitro is a major determinant of flow. Hence in man and experimental animals, as demonstrated in the brain, the area of ischaemia or non-perfusion following arterial occlusion is greatest at high PCV values. Patients with polycythaemia due to hypoxic lung disease have a poor prognosis. The hypoxic pulmonary vasoconstriction combined with the high blood viscosity causes an increase in pulmonary vessel resistance. PCV reduction of 0.50-0.52 leads to an improvement in work performance and mental alertness, and reduction in pulmonary vascular resistance.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Rheology of the absolute polycythaemias. 332 60

Acral ischemia with lividity is a well-described dermatologic sign in the myeloproliferative diseases polycythemia vera and essential thrombocythemia. It has not previously been reported as a sign of chronic myelogenous leukemia (CML). We suggest the term acral lividosis to describe this clinical entity in patients with any myeloproliferative disease. We propose that the pathophysiology of acral lividosis in CML involves occlusion of small blood vessels of the skin by large, nondeformable myeloblasts, a process that has been shown histologically to occur in other organs in patients with CML. This process, called leukostasis, occurs in patients with CML who have over 50.0 X 10(9)/L (50,000/mm3) circulating myeloblasts. Patients manifest cardiorespiratory and central nervous system compromise, a clinical constellation known as the hyperleukocytosis syndrome. Acral lividosis occurred in a patient with CML in whom nearly every organ demonstrated leukostasis on autopsy.
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PMID:Acral lividosis--a sign of myeloproliferative diseases. Hyperleukocytosis syndrome in chronic myelogenous leukemia. 347 43

Packed red cell volume (VPRC) and total blood volume chiefly affect oxygen transport to tissues and produce the syndrome of polycythemic hyperviscosity. Several studies have demonstrated that a raised VPRC increases the blood viscosity and, under a measured pressure, decreases the flow rate in a capillary tube. Reduced flow results in a less effective tissue perfusion. The oxygen transport at different values of VPRC is shown by an inverted arc-like curve: at normal VPRC levels the oxygen transport is optimal. Hypervolemia affects oxygen transport to tissues: at the same VPRC values, hypervolemic patients have a better oxygen transport. In polycythemia vera (PV), hypervolemia may partially reduce the damage due to the increased blood viscosity. However, in some local areas where fixed vessel diameter (from arteriosclerosis) limits the increased blood flow, hyperviscosity may result in a local tissue ischemia. A relative iron deficiency with associated microcytosis due to venesection frequently occurs in PV. It is also associated with a delayed red blood cell filtration which may contribute to hyperviscosity. When thrombocytosis is present, the risk of thrombotic complications is furthermore increased. We report symptoms and signs at the onset in a series of 80 patients affected by PV. All patients have a minimum follow-up of 4 years. We also report the course of the illness, the treatment effectiveness (venesection, dibromomannitol) on clinical symptoms, the survival curve with analysis of prognostic factors at the onset and the causes of death.
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PMID:[Polycythemic hyperviscosity syndromes]. 667 89

Essential thrombocythemia is a clonal myeloproliferative disorder, characterized predominantly by a markedly elevated platelet count without known cause. We report a case that was recognized during investigation of a transient ischemic attack, and review the neurologic findings in 33 patients with unequivocal essential thrombocythemia under prospective study by the Polycythemia Vera Study Group. Twenty-one patients had neurologic manifestations at some point during their course, including headache (13 patients), paresthesiae (10), posterior cerebral circulatory ischemia (9), anterior cerebral circulatory ischemia (6), visual disturbances (6) and epileptic seizures (2). All patients with neurologic symptoms responded satisfactorily to treatment, although continuous or repeated treatment was often required. Therapeutic recommendations include plateletpheresis for major thrombo-hemorrhagic phenomena, or megakaryocyte suppression with radioactive phosphorus, alkylating agents (such as melphalan), or hydroxyurea; minor symptoms may respond to platelet antiaggregating agents.
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PMID:Neurologic manifestations of essential thrombocythemia. 668 92

The aim of this study was to determine the frequency and characteristics of peripheral neuropathy associated to polycythemia vera. A prospective clinical and electrophysiological study was performed of 28 patients with polycythemia vera. Other causes of neuropathy were excluded. Eleven patients experienced paresthesiae, which were usually mild. In 13 (46%) patients, clinical examination revealed features suggesting polyneuropathy. Nerve conduction indexes were abnormal in 20 (71%) patients, suggesting the presence of a predominantly sensory axonal polyneuropathy. In the somatosensory evoked potentials a delay of the P40 wave was seen in 17 patients, while 11 exhibited a delay of the N20 wave. Three of these patients also showed bilateral increases in the I-III, I-V and III-V intervals of brain-stem evoked potentials. In most cases, the delay was moderate and symmetrical. No differences in sex, age, duration of disease, hematocrit values, or platelet counts were found between patients with or without clinical or electrophysiological polyneuropathy. A high percentage of patients with polycythemia vera present clinical or electrophysiological signs of predominantly sensory axonal polyneuropathy which is probably secondary to ischemia, due to increased blood viscosity and platelet dysfunction.
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PMID:Peripheral neuropathy associated with polycythemia vera. 895 Aug 63

Fifty consecutive patients with thrombocythemia (35 men and 15 women) were diagnosed as primary thrombocythemia (PT) in 30 and thrombocythemia associated with polycythemia vera (PV) in 20. The symptoms were platelet-mediated erythromelalgia in 16 PT and 15 PV, coronary artery disease in 3 PT and 2 PV, atypical cerebral ischemic attacks in 8 PT and 3 PV, paradoxical thrombosis and bleeding in 3 PT and 2 PV and hemorrhages alone in 6 PT and 2 PV patients. Erythromelalgia was localized in the forefoot sole and toes in 28, the fingertips in 9, the handpalm in 2. Untreated erythromelalgia progressed to acrocyanosis or peripheral ischemia with necrosis in a toe or fingertip in 14 cases. Painful red, warm and indurated erythromelalgic hot spots in the skin of the upper legs were misdiagnosed as superficial thrombophelebitis in 5 PT and 2 PV patients. Erythromelalgia in thrombocythemia already occurred at slightly increased platelet counts above 400 x 10(9)/l. The curative effect of aspirin on erythromelalgia in thrombocythemia was consistently accompanied by a significant increase of platelet counts. Erythromelalgia and bleeding paradoxically occurred in 5 patients at platelet counts between 1000 and 2000 x 10(9)/l. In this situation aspirin prevents erythromelalgic and microcirculatory circulation disturbances, but further increases the risk of serious bleeding complications. Presenting hemorrhagic manifestations in thrombocythemia were observed at platelet counts in excess of 1000 x 10(9)/l in 9 PT and 4 PV patients as severe epistaxis in 5, atypical ecchymoses in 3, gastrointestinal bleeding in 2 and secondary bleeding in 3. The concept of platelet-mediated erythromelalgia, thrombosis and hemorrhages in thrombocythemia is discussed.
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PMID:Erythromelalgic, thrombotic and hemorrhagic manifestations in 50 cases of thrombocythemia. 895 72


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