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Query: UMLS:C0002878 (hemolytic anemia)
 7,530 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thrombotic microangiopathic hemolytic anemia (TMHA) caused by antiphospholipid syndrome (APS) is generally associated with renal or neurological complications and plasma exchange is the first line of treatment. We present the case of a 72-year-old woman with APS who had chronic TMHA and pulmonary hypertension without other major complications. TMHA and pulmonary hypertension were refractory to plasma exchange but were treated successfully with anticoagulant monotherapy. Contrast-enhanced computed tomography and perfusion scintigraphy did not detect signs of pulmonary embolism. TMHA localized in pulmonary microvasculature which causes pulmonary hypertension is a very rare complication of APS.
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PMID:Pulmonary thrombotic microangiopathic hemolytic anemia treated successfully with anticoagulant monotherapy. 2055 47

Thrombotic microangiopathies (TMAs) are pathological conditions characterized by generalized microvascular occlusion by platelet thrombi, thrombocytopenia, and microangiopathic hemolytic anemia. Two typical phenotypes of TMAs are hemolytic- uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Other disorders occasionally present with similar manifestations. Depending on whether renal or brain lesions prevail, two pathologically indistinguishable but somehow clinically different disorders have been described: HUS and TTP. Injury to the endothelial cell is the central and likely inciting factor in the sequence of events leading to TMA. Loss of physiological thromboresistance, leukocyte adhesion to damaged endothelium, complement consumption, abnormal von Willebrand factor release and fragmentation, and increased vascular shear stress may then sustain and amplify the microangiopathic process. Intrinsic abnormalities of the complement system and of the von Willebrand factor pathway may account for a genetic predisposition to the disease that may play a paramount role in particular in familial and recurrent forms. In the case of diarrhea-associated HUS (D+HUS), renal endothelial damage is mediated (at least in large part) by the bacterial agent Shigatoxin (Stx), which is actually a family of toxins elaborated by certain strains of Escherichia coli and Shigella dysenteriae. Outcome is usually good in childhood, Shiga toxin-associated HUS, whereas renal and neurological sequelae are more frequently reported in adult, atypical, and familial forms of HUS and in TTP. Recent studies have demonstrated that deficiency in the von Willebrand factor cleaving protease ADAMTS13, due to deficiency of ADAMTS13 can be genetic or more common, acquired, resulting from autoimmune production of inhibitory anti-ADAMTS13 antibodies, that causes TTP. During the last decade, atypical HUS (aHUS) has been demonstrated to be a disorder of the complement alternative pathway dysregulation, as there is a growing list of mutations and polymorphisms in the genes encoding the complement regulatory proteins that alone or in combination may lead to aHUS. Approximately 60% of aHUS patients have so-called 'loss-of-function' mutations in the genes encoding the complement regulatory proteins, which normally protect host cells from complement activation: complement factor H (CFH), factor I (CFI) and membrane cofactor protein (MCP or CD46), or have 'gain-of-function' mutations in the genes encoding the complement factor B or C3. In addition, approximately 10% of aHUS patients have a functional CFH deficiency due to anti-CFH antibodies. Although TMAs are highly heterogeneous pathological conditions, one-third of TMA patients have severe deficiency of ADAMTS13. Platelet transfusions are contraindicated. Plasma infusion or exchange (PE) is the only treatment of proven efficacy.
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PMID:Thrombotic microangiopathies: thrombotic thrombocytopenic purpura / hemolytic uremic syndrome. 2110 95

Thrombotic microangiopathies are disorders resulting from platelet thromboses forming in the microvasculature with resultant schistocyte forms. Hemolytic uremic syndrome (HUS) is a microangiopathic hemolytic anemia often complicated by acute renal failure in children. HUS is typically caused by bacterial infection, most commonly enterohemorrhagic Escherichia coli. Neuraminidase-producing organisms, such as Streptococcus pneumoniae have also been reported as potential etiologies. The pathogenesis in these cases involves cleavage of sialic acid residues from the surfaces of erythrocytes, platelets, and glomerular capillary endothelial cells, exposing the Thomsen-Friedenreich antigen, a process known as T-activation. We describe a 2-year-old girl who presented with pneumococcal pneumonia and sepsis ultimately resulting in a thrombotic microangiopathy with acute renal failure, most consistent with HUS. The patient's direct antiglobulin test was positive. Polyagglutination was observed with human adult serum, but not with umbilical cord serum. Her red blood cells (RBCs) were reactive against peanut and soybean lectins, but not Salvia sclarea or Salvia horminum lectins. These findings are consistent with T-activation. Clinicians should be cognizant of the possibility of T-activation with resultant HUS in patients infected with neuraminidase-producing bacteria. Such patients may be difficult to identify using monoclonal typing antisera, as these typically do not have anti-T antibodies. Whether such patients are at risk for transfusion-associated hemolysis is debatable.
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PMID:Pneumococcal Induced T-activation with Resultant Thrombotic Microangiopathy. 2115 50

Thrombotic microangiopathies comprise different entities, including hemolytic uremic syndrome (HUS), thrombotic thrombocytopenic purpura (TTP), and several other conditions. TTP is characterized by hemolytic anemia, thrombocytopenia, and multiorgan failure. TTP is the result of severe von Willebrand factor multimer cleaving protease (ADAMTS13) deficiency that is either inherited or the result of acquired autoantibodies. We report a critically ill 2-year-old girl with invasive pneumococcal disease associated HUS (p-HUS) whose condition was complicated by severe ADAMTS13 deficiency, without detectable inhibitor, in a context of multiple organ failure. The patient recovered with supportive treatment, and ADAMTS13 activity normalized without plasmatherapy. Severe ADAMTS13 deficiency appears to be a manifestation of transient endothelial cell injury in the context of severe sepsis, including invasive p-HUS. The choice of appropriate therapy should not be based on this finding.
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PMID:Severe transient ADAMTS13 deficiency in pneumococcal-associated hemolytic uremic syndrome. 2116 Dec 82

Thrombotic microangiopathies are characterized by platelet activation, endothelial damage, hemolysis and microvascular occlusion. This group of diseases is primary represented by thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). Patients present with microangiopathic hemolytic anemia and thrombocytopenia as well as occlusion-related organ ischemia to a variable degree. A deficiency of the metalloprotease ADAMTS-13 is a major risk for acute disease manifestation as this is a regulator of unusually large von Willebrand factor (vWF) multimers, which are extremely adhesive and secreted by endothelial cells. In classical TTP an ADAMTS-13 activity below 5% is specific, whereas in other forms of thrombotic microangiopathies activity of ADAMTS-13 ranges from very low to normal. Symptoms of different forms of thrombotic microangiopathy are frequently overlapping and a clear classification according to clinical criteria is often difficult. Due to a high mortality, particularly of TTP, immediate diagnosis and therapy are essential. In this article two cases of thombotic microangiopathy after cardiac surgery are reported. After exclusion of TTP and HUS as well as other etiologies of thrombotic microangiopathy a relationship between the use of extracorporeal circulation and the pathogenesis of thrombotic microangiopathy is assumed.
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PMID:[Thrombotic microangiopathy after extracorporeal circulation: important differential diagnosis]. 2118 40

Thrombotic microangiopathies are a group of microvascular disorders, with reduced organ perfusion and hemolytic anemia. The two most relevant conditions characterized by thrombotic microangiopathic anemia (TMA) are thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). In TTP, systemic microvascular aggregation of platelets causes ischemia in the brain and other organs. In HUS, platelet-fibrin thrombi predominantly occlude the renal circulation. TTP can be inherited due to deficiencies in the activity of von Willebrand factor cleaving protease (ADAMTS13) or acquired due to the presence of autoantibodies directed against ADAMTS13. The majority of HUS cases are secondary to infections by strains of Escherichia coli that produce Shiga-like toxins (Stx-HUS), while about 5- 10% of all cases are classified as atypical HUS (aHUS). Genetically derived impaired regulation of the complement system is associated with aHUS. Infusion or the exchange of fresh frozen plasma have ameliorated the prognosis of TMA; however, no specific therapies aimed at preventing or limiting the microangiopathic process have been proven to affect the course of TMA. Large mammals, small animal models, knockout and transgenic mouse models of TTP and both Stx-HUS and aHUS have been developed and have provided outstanding contributions to nearly all areas of TMA research. A better understanding of the key clinical features of the diseases and of the importance of genetic and/or environmental factors involved in the pathogenesis of the diseases have been obtained. These animal models have also allowed the set up of protocols aimed at ameliorating the clinical approach to patients and for the development of new drugs and vaccines.
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PMID:Thrombotic microangiopathies: from animal models to human disease and cure. 2125 31

Thrombotic microangiopathies encompass a group of disorders characterized by microangiopathic hemolytic anemia, thrombocytopenia associated with hyaline thrombi (comprised primarily of platelet aggregates in the microcirculation), and varying degrees of end-organ failure. Many primary (genetic) and secondary etiological predisposing factors have been described-namely pregnancy, autoimmune disorders, cancer, drugs and antineoplastic therapy, bone marrow transplantation/solid organ transplantation, and infections. In the setting of infectious diseases, the association with Shiga or Shiga-like exotoxin of Escherichia coli 0157:h7 or Shigella dysenteriae type 1-induced typical hemolytic uremic syndrome is well known. Recently however, an increasing body of evidence suggests that viruses may also play an important role as trigger factors in the pathogenesis of thrombotic microangiopathies. This is a comprehensive review focusing on the current understanding of viral associated/induced endothelial stimulation and damage that ultimately leads to the development of this life-threatening multisystemic disorder.
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PMID:Viral-associated thrombotic microangiopathies. 2172 65

Abundant hemolysis is associated with a number of inherent and acquired diseases including sickle-cell disease (SCD), polycythemia, paroxysmal nocturnal hemoglobinuria (PNH) and drug-induced hemolytic anemia. Despite different etiopathology of hemolytic diseases, many concomitant symptoms are comparable and include e.g. hypertension, hemoglobinuria and hypercoagulation state. Studies in the last years have shown a growing list of mechanisms lying at the basis of those symptoms, in particular irreversible reaction between cell-free hemoglobin (Hb) and nitric oxide (NO) - endogenous vasorelaxant and anti-thrombotic agent. Saturation of protective physiological cell-free Hb-scavenging mechanisms results in accumulation of Hb in plasma and hemoglobinemia. Extensive hemoglobinemia subsequently leads to hemoglobinuria, which may cause kidney damage and development of Fanconi syndrome. A severe problem in patients with SCD and PNH is pulmonary and systemic hypertension. It may lead to circulation failure, including stroke, and it is related to abolition of NO bioavailability for vascular smooth muscle cells. Thrombotic events are the major cause of death in SCD and PNH. It ensues from lack of platelet inhibition evoked by Hb-mediated NO scavenging. A serious complication that affects patients with excessive hemolysis is erectile dysfunction. Also direct cytotoxic, prooxidant and proinflammatory effects of cell-free hemoglobin and heme compose the clinical picture of hemolytic diseases. The pathophysiological role of plasma Hb, mechanisms of its elimination, and direct and indirect (via NO scavenging) deleterious effects of cell-free Hb are presented in detail in this review. Understanding the critical role of hemolysis and cell-free Hb is important in the perspective of treating patients with hemolytic diseases and to design new effective therapies in future.
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PMID:[Pathophysiological consequences of hemolysis. Role of cell-free hemoglobin]. 2210 Jul 95

Thrombotic microangiopathies are a rare group of disorders with features such as microangiopathic haemolytic anaemia, thrombocytopenia and renal failure. Thrombotic microangiopathy has been previously reported in association with envenomation from a number of snake species. We present the first two reported cases of thrombotic microangiopathy caused by envenomation from the common tiger snake (Notechis scutatus). Both patients had classical features of thrombotic microangiopathy with microangiopathic haemolytic anaemia, thrombocytopenia and renal failure commencing in the first 48 hours after envenomation. The presentations and recovery were similar to case presentations of other snakebite envenomation associated thrombotic microangiopathies. Normal ADAMTS13 activity suggests that plasmapharesis may not be beneficial, although this needs further investigation.
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PMID:Thrombotic microangiopathy in two tiger snake envenomations. 2216 69

Thrombotic microangiopathies (TMAs) represent a heterogeneous group of diseases characterized by a microangiopathic hemolytic anemia, peripheral thrombocytopenia, and organ failure of variable severity. TMAs encompass thrombotic thrombocytopenic purpura (TTP), typically characterized by fever, central nervous system manifestations and hemolytic uremic syndrome (HUS), in which renal failure is the prominent abnormality. In patients with cancer TMAs may be related to various antineoplastic drugs or to the malignant disease itself. The reported series of patients with TMAs directly related to cancer are usually heterogeneous, retrospective, and encompass patients with hematologic malignancies with solid tumors or receiving chemotherapy, each of which may have distinct presentations and pathophysiological mechanisms. Patients with disseminated malignancy who present with microangiopathic hemolytic anemia and thrombocytopenia may be misdiagnosed as thrombotic thrombocytopenic purpura (TTP) Only a few cases of TTP secondary to metastatic adenocarcinoma are known in the literature. We present a case of a 34-year-old man with TTP syndrome secondary to metastatic small-bowel adenocarcinoma. Patients with disseminated malignancy had a longer duration of symptoms, more frequent presence of respiratory symptoms, higher lactate dehydrogenase levels, and more often failed to respond to plasma exchange treatment. A search for systemic malignancy, including a bone marrow biopsy, is appropriate when patients with TTP have atypical clinical features or fail to respond to plasma exchange.
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PMID:A report of disseminated adenocarcinoma presenting as thrombotic thrombocytopenic purpura. 2218 35


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