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

Severe hypophosphatemia may be observed after the ingestion of certain antacids which complex phosphorus in the intestinal lumen. In severe burn cases, during realimentation after denutrition, during intense and prolonged hyperventilations responsible for respiratory alkalosis, in diabetic ketoacidosis and in alcoholics. Hypophosphatemia lead to erythrocyte abnormalities which may eventually approach hemolysis, to phagocytosis and platelet function disorders and to neurological troubles which suggest a metabolic encephalopathy, a myopathy, a metabolic acidosis or a change in hepatic functioning. Treatment for hypophosphatemia with milk and sodium or potassium phosphate must be begun as soon as possible and must be sufficient to maintain blood phosphate levels above 10 mg/liter.
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PMID:[Hypophosphatemias (author's transl)]. 12 9

Sampling of brain tissue of two patients who died of dialysis encephalopathy syndrome have been studied using a combined electron microscope-electron microprobe x-ray analyzer. X-ray microanalysis showed that aluminium is present in high concentration in lysosomes of brain cells. This concentration is approximately one thousand-fold that which is normally measured in the grey matter. In these lysosomes, aluminium is present in needle like microcrystalline form of 0.006 micron diameter and 0.08 micron long on the average; in these crystals, aluminium is associated with phosphorus in a ratio of one atom of aluminium per atom of phosphorus. Similar lesions have been observed in the rat after intraperitoneal injections of water-soluble aluminium salts.
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PMID:[Progressive myoclonic encephalopathy in dialysis patients: presence of high concentrations of aluminium in the lysosomes of the cerebral cells (author's transl)]. 53 Aug 24

The progressive encephalopathy observed in 5 children with chronic renal failure was clinically similar to the so-called dialysis encephalopathy of adults, except that it was not related to dialysis therapy. Renal osteodystrophy is more prevalent in children than in adults and often more severe. The attempt to control the crippling deformities of renal osteodystrophy in growing children with renal insufficiency has led to the use of large quantities of aluminum containing antacids. The encephalopathy observed in children with chronic renal failure may be related to the oral ingestion of aluminum containing compounds in the presence of persistent secondary hyperparathyroidism. We suggest that alternative methods for the adequate control of serum phosphorus levels should be sought and indications for parathyroidectomy in children reevaluated. During the past 18 mos we have lowered the dose of aluminum containing compounds to 50 to 100 mg/Kg/day in our patients with progressive renal failure and recommend parathyroidectomy. No new cases of the encephalopathy have occurred.
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PMID:Encephalopathy in children with chronic renal failure. 61 6

Magnetic resonance spectroscopy (MRS) is a flexible tool with real clinical utility. Examples from our experience in over 250 cases of clinical proton MRS are presented. Shorter echo time and reproducible water suppression increases the number of metabolites which can be detected and identified. Case reports illustrate the significance of altered ratios of N-acetylaspartate, choline, total creatine, myo-inositol, glutamate, glutamine, lactate, glucose, ketones, and, as an incidental finding, ethanol. Significant new information has resulted by applying proton MRS in chronic hepatic encephalopathy, diabetes mellitus and severe hypoxic encephalopathy ('near-drowning'). Potentially useful measurements have been made in normal brain maturation, ethanol related diseases, dementia (normal-pressure hydrocephalus), urea cycle defect and neuronal disease presenting as seizures. Metabolite imaging, particularly with proton, is clinically valuable, documenting the heterogeneity of biochemical disorders in seemingly focal lesions. A new method of specific 31-phosphorus--phosphocreatine imaging provides information in partially denervated skeletal muscle and is expected to have applications in brain.
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PMID:Clinical tools for the 90s: magnetic resonance spectroscopy and metabolite imaging. 156 13

Phase-modulated rotating frame imaging is a modification of magnetic resonance spectroscopy, which uses a linear radiofrequency field gradient to obtain spatially localized biochemical information. Phase-modulated rotating frame imaging was used to study regional cerebral energy metabolism in the brains of 9 normal newborns and 25 newborns after birth asphyxia. Relative concentrations of phosphorus-containing metabolites and intracellular pH were determined for brain tissue at three specified depths below the brain surface for all neonates. Wide variations in metabolite ratios were seen among normal neonates, and considerable metabolic heterogeneity was demonstrated in individual neonates by depth-resolved spectroscopy. Asphyxiated neonates with severe hypoxic-ischemic encephalopathy and a poor neurodevelopmental outcome showed the expected rise in inorganic orthophosphate and fall in phosphocreatine concentrations in both global and spatially localized spectra. Phase-modulated rotating frame imaging showed that metabolic derangement was less in superficial than in deeper brain tissue. The inorganic orthophosphate-adenosine triphosphate ratio from 1 to 2 cm below the brain surface was more accurate than any global metabolite ratio for the identification of neonates with a poor short-term outcome. These data are consistent with the known vulnerability of subcortical brain tissue to hypoxic-ischemic injury in the full-term neonate.
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PMID:Spatially localized magnetic resonance spectroscopy of the brains of normal and asphyxiated newborns. 200 Feb 66

This study addresses mechanisms of the clinical, encephalopathic uremic illness and its suppression by dialysis. Renoprival rats were treated with peritoneal dialysis (8 exchanges per day, 30 min dwell), or untreated (attrition group), and their EEG's were automatically sampled overnight and subjected to power spectrum analysis as an index of encephalopathy. As in man the background rhythm of the quantified EEG (Q.EEG) in the attrition group slowed with time as extracellular fluid composition became increasingly abnormal; these changes were normalized by therapeutic dialysis (TD) using standard, commercial dialysate. However, Q.EEG slowing was only partially normalized by solute-specific dialysis using "mock uremic dialysate" (M-UD), prepared from laboratory chemicals to equal plasma concentrations in preterminal uremic rats of urea, creatinine, potassium, phosphorus, calcium, magnesium, bicarbonate, sodium, and chloride. When only phosphate was added to TD, the Q.EEG slowed to the same level achieved after M-UD. We conclude that uremic encephalopathy in this model is produced by an unknown neurotoxin and augmented by one or more of the M-UD solutes, phosphate being a likely candidate. To localize the encephalopathic effect, regional brain glucose uptake was estimated in 20 discrete brain areas. Significance of reduced uptake in three areas is discussed.
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PMID:Role of dialysable solutes in the mediation of uremic encephalopathy in the rat. 231 78

The metabolic basis of the encephalopathy associated with acute bacterial meningitis is unknown. The presence of cerebrospinal fluid lactic acidosis and hypoglycorrhachia suggests that intracellular acidosis or cellular energy depletion may play a role. Phosphorus magnetic resonance spectroscopy allows for the noninvasive determination of intracellular pH and relative amounts of phosphate-containing metabolites in humans. In seven normal volunteers, the intracellular pH of a mixed volume of gray and white matter was 7.00 +/- 0.04 (mean +/- SD). The apparent relative intensities of resonances from adenosine triphosphate, phosphocreatine, phosphodiesters and phosphomonoesters, and inorganic phosphate were measured. An encephalopathic patient with pneumococcal meningitis who had severe cerebrospinal fluid lactic acidosis was studied. Brain intracellular pH and relative phosphate metabolite concentrations were normal. Intracellular acidosis and bioenergetic compromise are therefore not causes of encephalopathy in this disease. This also demonstrates that the human brain can maintain tight control of intracellular pH even in the presence of marked extracellular metabolic acidosis.
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PMID:Brain phosphorus magnetic resonance spectroscopy in acute bacterial meningitis. 277 14

A 29-year-old single woman had recurrent stroke-like episodes. She developed loss of consciousness, myoclonic seizures, and lactic acidosis. She died at the age of 30. A muscle biopsy study revealed mitochondrial myopathy, and the postmortem biochemical analysis demonstrated decreased cytochrome c oxidase activity in the skeletal muscles by 20% of normal control. The brain had multiple ischemic lesions in the cerebral cortex without major vascular occlusions. We present this case as an autopsy case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) with a partial deficiency of cytochrome c oxidase. The analytical electron microscopic study of the calcified small vessels in the globus pallidus revealed increased calcium, phosphorus and iron. No accumulation of chromium, nickel or zinc was noted in this case, which was different from the previously reported cases of basal ganglia calcification.
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PMID:An autopsy case of mitochondrial encephalomyopathy: biochemical and electron microscopic studies of the brain. 284 99

This paper discusses the possible pathogenesis of the cerebral atrophy (CA) observed in a large percentage of uraemic patients, taking the form of prevalently cortical damage (cortical atrophy) and/or subcortical enlargement of ventricular cavities (subcortical atrophy). This central nervous system pathology seems to share very little either with the better known 'dialysis encephalopathy' or with the 'acute encephalopathy syndrome', even though sporadic cases of both these forms have shown concomitant CA. Histopathologically it offers the picture of loss of neurons and nerve fibres and can thus be compared with uraemic peripheral nervous system damage. CA is unquestionably important because of its implications in terms of impairment of superior cortical functions, just as in CA of non-uraemic aetiology. A first aetiopathogenic hypothesis might include endogenous uraemic intoxication to the nerve tissue, believed responsible for peripheral uraemic neuropathy, but other possibilities merit consideration: vascular calcification secondary to hyperparathyroidism, blood lipid disorders, and systemic hypertension--factors that contribute to impairing the brain vasculature, with cascade effects on brain tissue oxygenation, neuronal metabolism, and energy exchanges. Tissue oxygenation is already jeopardized in the uraemic patient by the concomitant chronic anaemia and by cardiac insufficiency in cases with hypertensive heart disease. In dialysis patients with volume-dependent hypertension the brain may be further damaged by abrupt pressure changes produced by dialytic ultrafiltration; these constitute a severe challenge to cerebral blood flow autoregulation. Cyclic variations of brain tissue hydration connected with regular dialysis treatment may have adverse effects on neurotransmitter functions, particularly those mediated by neuropeptidergic systems. Chronic intoxication may result from oral Al(OH)3 of phosphorus-chelating agents: in animal studies and clinical observations in non-uraemic populations the neurotoxic potential of Al is indicated by a significant correlation between histological neuronal damage, impaired function, and Al concentration in brain tissues. In addition, a concausal role of malnutrition in central nervous system damage in the uraemic patient cannot be overlooked, since malnutrition is known to give rise to functional and structural alterations in non-uraemic human pathology. In the light of these clinical observations and experimental findings, it would appear that the prevention of CA in uraemia is today feasible.
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PMID:Pathogenesis of cerebral atrophy in uraemia. State of the art. 328 91

Accumulation of aluminum occurs in children with renal failure and can cause anemia, disabling osteodystrophy, and encephalopathy. Effects on bone mineralization are of particular concern in pediatric patients with growth potential. We measured plasma aluminum levels in 36 patients on continuous ambulatory peritoneal dialysis (CAPD) and 22 on hemodialysis under surveillance at a single pediatric center. The levels were above normal in 35 and 21 patients, respectively, and the values correlated with the oral dose of aluminum-containing phosphate-binding medications (r = 0.57; P less than 0.001). Younger and smaller children had higher plasma aluminum levels and also received larger doses of oral aluminum-containing compounds. Mean plasma aluminum levels (57.2 +/- 52.8 and 48.7 +/- 32.1 micrograms/liter, respectively) and the daily oral doses of elemental aluminum (47.3 +/- 37.6 and 39.2 +/- 26.7 mg/kg, respectively) were not statistically different in patients on CAPD and those on hemodialysis. Plasma aluminum levels did not correlate with estimated cumulative oral intake of aluminum, total duration of dialysis, serum calcium and phosphorus concentrations, N-terminal parathyroid hormone levels, or transfusion requirements. Retention of aluminum is common in children undergoing dialysis, correlates with the amount of aluminum administered orally, and results in similar elevations of plasma aluminum with CAPD and hemodialysis. Younger and smaller children are at increased risk for accumulation of aluminum. Alternative methods for control of serum phosphorus are needed in children with end-stage renal disease.
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PMID:Plasma aluminum levels in pediatric dialysis patients: comparison of hemodialysis and continuous ambulatory peritoneal dialysis. 356 Oct 41


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