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

Cerebral infarction is a frequent, severe complication of sickle cell anaemia. During childhood, most strokes are due to infarction with the majority resulting from occlusion of the large cerebral arteries. Risk factors include transient ischaemic attacks, acute chest syndrome, severe anaemia and elevated blood pressure. Less certain is the association with leucocytosis, or protection provided by alpha-thalassaemia or fetal haemoglobin. Children who have one stroke are at significant risk for having subsequent events that can be substantially reduced by maintaining haemoglobin S below 30%. It has not yet been possible to identify individuals for whom transfusion can be safely stopped. Haemosiderosis is a consequence of intensive and long term transfusion therapy, which requires chelation with deferoxamine. Iron accumulation can be minimised using erythrocytapheresis but this is technically difficult in children, expensive and results in increased donor exposure. In addition to lesions associated with strokes, an additional 17% of patients can be shown to have clinically silent cerebral infarcts. Although these are termed 'silent', those affected have mild neuropsychological deficits. Their relationship to stroke or risk for recurrence is unknown. Transfusion therapy has been shown to provide primary stroke prevention for children who have elevated cerebral artery velocity. Finally, intracranial haemorrhages, more commonly found in adults, also affect children. Subarachnoid haemorrhage is frequently found to result from cerebral artery aneurysms. A condition that mimics the moyamoya syndrome radiographically, as well as for its risk of haemorrhage, can be found in children with partly occluded cerebral arteries either as a result of stroke or silent infarct.
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PMID:Stroke in children with sickle cell anaemia: aetiology and treatment. 1143 87

The phenotypic expression of sickle cell anaemia varies greatly among patients and longitudinally in the same patient. It influences all aspects of the life of affected individuals including social interactions, intimate relationships, family relations, peer interactions, education, employment, spirituality and religiosity. The clinical manifestations of sickle cell anaemia are protean and fall into three major categories: anaemia and its sequelae;pain and related issues; andorgan failure including infection. Recent studies on the pathogenesis of sickle cell anaemia have centred on the sequence of events that occur between polymerisation of deoxy haemoglobin (Hb) S and vaso-occlusion. Cellular dehydration, inflammatory response and reperfusion injury seem to be important pathophysiological mechanisms. Management of sickle cell anaemia continues to be primarily palliative in nature, including supportive, symptomatic and preventative approaches to therapy. Empowerment and education are the major aspects of supportive care. Symptomatic management includes pain management, blood transfusion and treatment of organ failure. Pain managment should follow certain priniciples that include assessment, individualisation of therapy and proper utilisation of opioid and nonopioid analgesics in order to acheive adequate pain relief. Blood selected for transfusion should be leuko-reduced and phenotypically matched for the C, E and Kell antigens. Exchange transfusion is indicated in patients who are transfused chronically in order to prevent or delay the onset of iron-overload. Acute chest syndrome is the most common form of organ failure and its management should be agressive, including adequate ventilation, multiple antibacterials and simple or exchange blood transfusion depending on its severity. Preventitive therapy includes prophylactic penicillin in infants and children, blood transfusion (preferably exchange transfusion) in patients with stroke, and hydroxyurea in patients with frequent acute painful episodes. Bone marrow and cord blood transplantation have been successful modalities of curative therapy in selected children with sickle cell anaemia. Newer approaches to preventative therapy include cellular rehydration with agents that inhibit the Gardos channel or the KCl co-transport channel. Curative gene therapy continues to be investigational at the level of the test tube and transgenic mouse models.
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PMID:Sickle cell anaemia: progress in pathogenesis and treatment. 1201 77

Stroke is the most common neurologic complication of sickle cell disease. Acute chest syndrome (ACS) is a known risk factor for stroke in this population. Two patients (a 12-year-old boy and a 6-year-old girl) developed acute change of mental status and focal neurologic signs during episodes of ACS. The clinical and radiologic findings were compatible with acute necrotizing encephalitis, a variant of acute demyelinating encephalomyelitis. Patients with acute neurologic deterioration in conjunction with ACS should be evaluated thoroughly for other causes of central nervous system disease including infectious/parainfectious processes as well as stroke.
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PMID:Unusual encephalopathy after acute chest syndrome in sickle cell disease: acute necrotizing encephalitis. 1236 3

Severe hypoxia occurs in patients with acute chest syndrome, and erythrocytapheresis has been shown to improve oxygenation. Patients with sickle cell anemia also have decreased baseline oxygen saturation values, but the effect of erythrocytapheresis on steady-state oxygenation has not been well studied. We investigated the changes in oxygen saturation versus hematocrit, fraction of hemoglobin A, and transfusion volume during 71 prophylactic erythrocytapheresis procedures performed in 5 stable patients with sickle cell anemia. Each patient had a history of either acute chest syndrome or stroke, but no serious events occurred while enrolled in the chronic exchange program. The oxygen saturation improved from 1% to 6% during erythrocytapheresis in each of our patients (p < 0.001) regardless of preprocedure saturation level or total hematocrit. We have shown that decreased baseline oxygen saturation in sickle cell disease is related to abnormal hemoglobin S levels, and oxygen saturation can be improved with erythrocytapheresis, independent of any change in the total hematocrit.
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PMID:Oxygen saturation and hemoglobin A content in patients with sickle cell disease undergoing erythrocytapheresis. 1242 35

Hematopoietic cell transplantation (HCT) has been used for more 30 years for the treatment of selected malignant and nonmalignant diseases. Traditionally, HCT for hematological disorders has relied on myeloablative conditioning before HLA-identical sibling bone marrow transplantation to correct the underlying hematological defect. Most children with hematological diseases who are referred to HCT have features that portend significant morbidity and early mortality. Among SAA patients who have HLA-identical sibling donors, younger patients with profound pancytopenia might be considered early for HCT. For others who lack sibling donors, patients who receive HCT from alternate sources have generally failed one or more courses of intensive immunosuppressive therapy and remain transfusion-dependent, some with hemosiderosis, red cell alloimmunization, and platelet transfusion refractoriness [44,46,48]. Currently, HCT for SCD is generally restricted to those who have experienced a significant sickle-related complication such as stroke, recurrent acute chest syndrome, or recurrent painful episodes [7,13]. In contrast, most reserve HCT in thalassemia for younger, Lucarelli class I, good-risk patients who have HLA-identical sibling donors, and veer away from older, high-risk thalassemics for whom transplantation is a riskier clinical intervention. For groups such as young adults with thalassemia major, HCT might become more widely applicable if its toxicity was reduced. Several approaches undergoing development include reduced-intensity conditioning and attempts to prevent GVHD. New methods to reduce the intensity and toxicity of conditioning as well as to use highly purified stem cells with the reduction in graft versus host disease may allow for the use of matched unrelated donors or haploidentical donors. This would serve to provide potentially more children who could benefit from stem cell transplantation with donors. These advances will hopefully lead to benefits for the majority of children who lack HLA-identical donors.
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PMID:New approaches to hematopoietic cell transplantation for hematological diseases in children. 1243 Jun 22

Sickle cell anemia (SCA) is one of the commonly inherited hemoglobinopathies in the Kingdom of Saudi Arabia. It is characterized by periods of remissions and exacerbations called crises as well as certain pathological phenomenon such as acute chest syndrome, priapism, hepatopathy, and cerebrovascular stroke. Blood transfusion (BT) as therapy and prophylaxis in SCA, although was advocated as early as the 1940's, there are still debates regarding its benefits and risks. This is a review of the value of BT in patients with SCA with emphasis on the risks and benefits as well as guidelines towards safe BT.
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PMID:Principles of blood transfusion in sickle cell anemia. 1251 88

Sickle cell disease is numerically as common as thalassaemia. However, it affects relatively under privileged population i.e. tribal population belonging to economically poor class and having inadequate access to education and modern health facilities. A recent explosion acknowledged in understanding the pathogenesis of this disease has lead to newer dimensions in treatment. Some of these viz. prevention of overwhelming bacterial infection, present indications and controversies regarding blood transfusion, prevention of stroke, acute chest syndrome, hydroxyurea therapy--probably the best disease modifying agent at the moment, stem cell transplantation--a cure and certain promising experimental therapies including gene therapy have been discussed in this review.
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PMID:Advances in management of sickle cell disease. 1451 86

Allogeneic haematopoietic cell transplantation (HCT) is presently the only treatment which offers the possibility of a cure for patients with sickle cell disease (SCD). While approximately 84% of patients survive disease-free after human leukocyte antigen (HLA)-identical sibling donor HCT, this therapy has traditionally been reserved for patients who have suffered serious complications due to the risk of transplant-related morbidity and mortality. Typically, these sickle-related complications have included recurrent episodes of acute chest syndrome, recurrent vaso-occlusive episodes and stroke. The future of HCT for haemoglobinopathies undoubtedly will evolve as transplant-related complications are reduced and as the process of selecting patients for HCT is refined.
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PMID:Haematopoietic cell transplantation in the treatment of sickle cell disease. 1464 Sep 47

Vascular cell adhesion molecule-1 (VCAM-1) has been implicated as being important in the pathophysiology of acute pain episodes (APE) and acute chest syndrome (ACS) of sickle cell disease (SCD). The frequency of these episodes is reduced by chronic transfusion therapy. The impact of chronic transfusion therapy on VCAM-1 expression is unknown. Soluble VCAM-1 (sVCAM-1) levels were measured in plasma using an ELISA assay (R&D Systems) in 61 patients with SCD (age range 1.5-20 years) and 12 normal controls (2.5-14 years). SCD patients included 20 with ACS, 14 with APE, 12 at well-child visits, and 15 receiving chronic transfusion therapy. Asymptomatic SCD patients had higher sVCAM-1 levels compared to normal subjects (P < 0.001). Levels of sVCAM-1 were further elevated during ACS (P < 0.001) and APE (P = 0.072) and returned to the asymptomatic range on resolution. Levels were significantly lower in transfused patients (P = 0.003) compared to asymptomatic SCD patients. Our findings of increased VCAM-1 expression during ACS and perhaps APE offer a rationale for therapeutic use of cytokine and other VCAM-1 modulators. The reduction of sVCAM-1 levels observed in our transfused SCD patients offers insight into the mechanism of the protective effect of transfusion against ACS and APE and possibly stroke.
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PMID:Elevated plasma sVCAM-1 levels in children with sickle cell disease: impact of chronic transfusion therapy. 1511 98

The distribution of clinical features was examined in subjects with homozygous sickle cell (SS) disease in the Jamaican Cohort Study to determine whether there is evidence of distinct clustering of symptoms or clinical phenotypes. A twofold model yielded groups that could be interpreted as painful crisis or leg ulcer phenotypes and 78% of patients were classified with 95% confidence into one of these. The painful crisis phenotype also manifested higher frequencies of dactylitis, meningitis/septicaemia, acute chest syndrome and stroke. Attempts to define a three-group model were less convincing although 43% of patients could be allocated with 95% confidence. The three-group model essentially divided subjects with the leg ulcer phenotype into subgroups with higher and lower frequencies of painful crisis, dactylitis, meningitis/septicaemia and acute chest syndrome. In the three-group model, the painful crisis phenotype had lower total haemoglobin, fetal haemoglobin, mean cell volume and higher reticulocytes but there was no apparent influence of alpha thalassaemia or beta globin haplotype. Both environmental and genetic factors are likely to contribute to most manifestations of SS disease and the evidence for different clinical phenotypes suggests that a search for associated genetic polymorphisms may provide insights into the mechanisms of clinical variability in SS disease.
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PMID:Are there clinical phenotypes of homozygous sickle cell disease? 1528 56


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