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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the presence of normal renal function, a high concentration of aluminum in drinking water has been implicated as a factor in the etiology of a neurological syndrome in one specific geographical area. The role of aluminum as a toxic agent in other neurological disorders, where renal function is normal, is controversial. Aluminum is absorbed from the gastrointestinal tract and is normally excreted by the kidneys in the urine. In patients with chronic renal failure, aluminum appears to be of proven toxicological importance. In these patients the accumulation of aluminum in tissues causes an encephalopathy (dialysis encephalopathy or dialysis dementia), a specific form of metabolic bone disease (osteomalacic dialysis osteodystrophy), and an anemia and also plays an etiological role in some of the other complications associated with end-stage chronic renal disease. A failure in the normal renal excretory mechanism accounts for the tissue accumulation in chronic renal failure. The majority of chronic renal failure patients who develop aluminum toxicity are on long-term treatment with either hemo- or peritoneal dialysis; some patients develop toxicity who are only on treatment with aluminum-containing phosphate-binding agents. Aluminum in the dialysate appears to be the major source of the metal in chronic renal failure patients who develop aluminum toxicity. The aluminum content of the dialysate depends primarily on the content of the water with which it is prepared; there may be some contribution from the chemicals used in the concentrate which is added to the water. Some domestic tap-water supplies contain aluminum in high concentration, either naturally or because aluminum has been added as a flocculant in the purification process.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Water content of aluminum, dialysis dementia, and osteomalacia. 390 86

Patients with aluminum accumulation show a heterogeneous distribution of the element throughout the body which is different from normals. In chronic renal failure, aluminum has been implicated in dialysis encephalopathy, vitamin D-resistant osteomalacia and microcytic hypochromic anemia. Disparities are observed between aluminum distribution and organ dysfunction. In patients with severe renal failure and aluminum overload, aluminum shows a heterogeneous distribution throughout the brain. The mechanisms of aluminum toxicity remain largely unknown. Desferrioxamine administration results in decreases of tissue aluminum levels and in regression of aluminum-associated pathology.
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PMID:Aluminum in tissues. 391 59

Four patients under maintenance dialysis for chronic renal failure were suffering from aluminium toxicity. One showed evidence of encephalopathy, two presented with fractures and one was asymptomatic. Hypercalcaemia was constant, whereas high serum aluminium levels were present in only 2 patients. In all cases, iliac bone biopsy specimens, non-decalcified and stained with Aluminium , were found to contain aluminium deposits along the mineralization fronts, thus confirming the diagnosis of aluminium overload. In addition, biopsies revealed an excess of osteoid tissue with morphological and dynamic signs of osteomalacia (2 cases) or strongly depressed bone formation (2 cases). Histomorphometric bone biopsy appears to be the best mean of diagnosing aluminium intoxication and analyzing its effects on bone remodeling and mineralization. It is also very useful to monitor the treatment.
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PMID:[Aluminum poisoning in renal dialysis patients: bone histology. Value of quantitative bone biopsy]. 623 88

Twelve patients with chronic renal failure, on maintenance hemodialysis have a stereotyped illness. The dialysate was made up from a high level aluminium tap water. After having been on haemodialysis for 10 to 12 months, they suffer from more and more acute osteodystrophic, osteomalacic symptoms. Then, distinctive EEG abnormalities appear. These first symptoms allow an early diagnosis of the progressive dialytic encephalopathy. The neurological symptoms appear some months later. Eight patients died from this encephalopathy. Four patients are still alive and are, from at least two years, on maintenance haemodialysis with a free aluminium water. In these 4 cases, the evolution of the disease is good: osteomalacic symptoms disappear in a year; the neurological symptoms are still present though transient. EEG abnormalities remain and blood aluminium level is about 100 micrograms/L. These cases show, once more, the significant role of aluminium as an aetiological factor in "progressive dialysis encephalopathy".
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PMID:[Chronological study of signs of myoclonic encephalopathy in hemodialysis patients (author's transl)]. 627 30

One of the most important complication of patients with chronic renal failure is osteodystrophy. This causes skeletal deformities, growth failure, bone pain and decreased physical activity. Osteodystrophy is more frequent among children than uraemic adults. In fact, 50-80% of children with chronic renal failure may occur in metabolic bone disease and the incidence tends to be higher in those children who have been in uraemic state for a long time before starting chronic haemodialysis. Osteodystrophy is a result of: 1) lesions of rickets; 2) lesions of osteitis fibrosa: 3) osteosclerosis. In contrast to adult, metastatic calcifications are virtually never observed in uraemic children. Hyperphosphoraemia, that is secondary to the reduction of G.F.R., may be the principal responsible of hyperparathyroidism that is the main cause of osteodystrophy. Hyperparathyroidism is also maintained and increased by deficit of 1,25(OH)2D3 which is responsible for lesions of rickets. Haemodialysis may markedly improve osteitis fibrosa and it is efficacious in reversing the mineral defect. Dialysate calcium concentration should be maintained at approximately 3,5 mEq/l. In this case we can raise serum calcium. On the contrary dialysate has to be lacking in phosphorus to correct hyperphosphoraemia. It must be noted that we have to prepare a dialysate with deionized water lacking in aluminum to avoid encephalopathy compliance.
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PMID:[Osteodystrophy in children with chronic renal insufficiency in dialysis therapy]. 628 42

Among patients with renal failure, there have been impressive modifications of both the duration and quality of life as a result of dialysis, renal transplantation, and improved medical management. However, patients who have renal failure continue to manifest a variety of neurologic disorders. Patients with chronic renal failure who have not yet received dialytic therapy may develop a symptom complex progressing from mild sensorial clouding to delirium and coma, with tremor, asterixis, multifocal myoclonus, and seizures. Even after the institution of otherwise adequate maintenance dialysis therapy, patients may continue to be afflicted with more subtle nervous system dysfunction, including impaired mentation, generalized weakness, and peripheral neuropathy. The central nervous system disorders of both untreated renal failure and that persisting despite dialysis are referred to as uremic encephalopathy. The dialytic treatment of end stage renal disease has itself been associated with the emergence of two distinct, new disorders of the central nervous system: Dialysis dysequilibrium and dialysis dementia. The dialysis disequilibrium syndrome consists of headache, nausea, muscle cramps, obtundation and seizures, and is a consequence of the initiation of dialysis therapy in some patients. Dialysis dementia is a progressive, generally fatal encephalopathy which affects patients on chronic hemodialysis. This disease also appears to be a complication of the therapy for renal failure.
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PMID:Pathogenesis of dialysis encephalopathy. 636 3

A patient with chronic renal failure, a dialysis encephalopathy syndrome and renal osteodystrophy associated with aluminium intoxication developed an avascular necrosis of the left femoral head. Histological examination of the excised head confirmed the zone of avascular necrosis and demonstrated an exuberant formation of cartilage around this zone. Calcification was sparse and the cartilage exhibited histological features similar to those seen in classical rickets. Histochemical and electron probe x-ray microanalysis demonstrated aluminium in the matrix around hypertrophic chondrocytes, at the tide mark of articular cartilage and at the mineralised tissue/osteoid interface of trabecular bone. Aluminium, therefore, preferentially localises at sites of calcification and possibly exerts an inhibitory effect on this reaction. This is taken to account for the relative failure of endochrondral ossification and the development of a rachitic appearance. A comparison with five other examples of avascular necrosis of the femoral head (occurring after renal transplantation, as an idiopathic phenomenon and as a complication of steroid therapy) showed that, in addition to the more commonly described appositional bone formation, cartilage formation and endochondral ossification were present in three of these comparison cases, although less prominent and of considerably less degree than in the main case.
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PMID:Consequences of avascular necrosis of the femoral head in aluminium-related renal osteodystrophy and the role of endochondral ossification in the repair process. 640 24

Plasma amino acid patterns were determined before and after hemofiltration (HF) and hemodialysis (HD) in 6 patients with portal systemic encephalopathy (PSE) and compared with the plasma AA patterns of 16 patients with chronic renal failure (CRF) treated either by HF or HD. The branched-chain amino acids (BCAA) increased paradoxically in PSE patients during HF but not with HD. There were no differences in BCAA's with HF as compared to HD in the CRF patients. The amount of amino acids lost was the same with both treatment modalities and in both patient groups. Much of the amino acids lost were released from the intracellular space. The BCAA release was significantly higher in PSE patients during HF. No correlation was found between plasma insulin, glucagon, and cortisol levels and BCAA release. An inverse correlation was found between the amount of BCAA's released from the intracellular space and the plasma ammonia levels. It is suggested that a selective cellular transport mechanism for BCAA exists which is inhibited by high plasma ammonia levels in PSE.
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PMID:Increased plasma ammonia may inhibit cellular release of branched-chain amino acids in systemic portal encephalopathy. 658 71

Bone tissue from a patient with chronic renal failure and a dialysis encephalopathy syndrome has been studied by histological and histochemical means, by flame emission spectroscopy and by electron probe X-ray microanalysis. There was significant renal osteodystrophy manifest as an osteomalacia. Emission spectroscopy showed the presence of iron (Fe), aluminium (Al), silicon (Si), zinc (Zn), strontium (Sr), lead (Pb) and copper (Cu) in the concentration range 100-1000 parts per million (ppm). Electron probe X-ray microanalysis showed focal concentrations of Fe and Si in the marrow tissue only, whereas Al was localized to the calcification front zones at the junction of osteoid and mineralized tissue of both trabecular and cortical bone. It is concluded that the presence of Al at these sites could interfere with the mineralization process and significantly contribute to the pathogenesis of haemodialysis-related osteomalacia and that it is unlikely that the other elements detected are significant in this regard.
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PMID:The localization of aluminium and other elements in bone tissue of a case of renal osteodystrophy with an associated dialysis encephalopathy syndrome. 671 13

Patients with renal failure may manifest a variety of neurologic disorders. Patients with chronic renal failure who have not yet received dialytic therapy may develop a symptom complex progressing from mild sensorial clouding to delirium and coma, with tremor, asterixis, multifocal myoclonus, and seizures. After the institution of adequate maintenance dialysis therapy, patients may continue to be afflicted with more subtle nervous dysfunction, including impaired mentation, generalized weakness, and peripheral neuropathy. These central nervous system disorders are referred to as uremic encephalopathy. The dialytic treatment of end-stage renal disease has itself been associated with the emergence of two distinct, new disorders of the central nervous system; dialysis dysequilibrium and dialysis dementia. The dialysis disequilibrium syndrome consists of headache, nausea, muscle cramps, obtundation, and seizures, and is a consequence of the initiation of dialysis therapy in some patients. Dialysis dementia is a progressive, generally fatal encephalopathy which affects patients on chronic hemodialysis. There are at least three different forms of dialysis encephalopathy: sporadic, epidemic; and that associated with renal disease in children. In addition to the foregoing neurologic diseases which are specifically related to uremia and/or dialysis, a number of other neurologic disorders occur with increased frequency in patients with end-stage renal disease on chronic hemodialysis. These include subdural hematoma, electrolyte disorders, vitamin deficiencies, drug intoxication, hypertensive encephalopathy, and acute trace element intoxication. Renal transplantation is associated with a variety of central nervous system infections, reticulum cell sarcoma, and central pontine myelinosis. The present manuscript will review the clinical, structural, and biochemical components of those neurologic disorders which are peculiar to the uremic state and its treatment with dialysis.
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PMID:Uremic encephalopathies: clinical, biochemical, and experimental features. 675 30


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