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

Inorganic lead produces cerebral dysfunction and clinically definable encephalopathies in man. To date there have been few studies on the biochemical changes in brain following exposure to inorganic lead. Studies correlating toxicity with behavioral and brain neurochemical changes following lead exposure have been hindered because adult laboratory animals are resistant to the central nervous system effects of lead poisoning. Such studies have been impeded by lack of suitable experimental models until Pentschew and Garro showed that brain lesions develop in neonatal rats when a pregnant rat newly delivered of her litter is placed on a 4% lead carbonate containing diet. Lead passes into the developing sucklings via maternal milk. Lead-poisoned new-borns have pronounced retardation of growth and during the fourth week of ilfe develop the severe signs of lead encephalopathy, namely, extensive histological lesions of the cerebellum, brain edema, and paraplegia. There is an approximate 85-fold increase in the lead concentration of both the cerebellum and cerebral cortex relative to controls, but edema and gross vascular changes are confined to the cerebellum. Ingested lead had little effect on RNA, DNA, and protein concentrations of developing rat cerebellum and cerebral cortex. However, there was a reduction of between 10 and 20% in the DNA content of the cerebellum around 3 weeks of age in the lead-exposed sucklings. This suggests a failure of cell multiplication in this part of the brain.A critical evaluation of this experimental approach indicated that under similar dietary conditions experimental lactating rats eat 30% less food than controls resulting in: (a) sustained loss in body weight of nursing mothers and that (b) offsprings who develop paraplegia and cerebellar damage do so after gaining access to lead containing diet. We have studied mothers' food consumption and body weight changes and blood, milk, and brain lead content; and newborns' body and brain weight changes, blood and brain lead content, and brain serotonin (5HT), norepinephrine (NE), dopamine (DA), and gamma-aminobutyric acid (GABA). We have found that a lactating mother rat eating 5% lead acetate (2.73% Pb) produced milk containing 25 ppm lead. When the mothers' diet is changed at day 16 from 5% PbAc to one containing 25 ppm Pb, and neonates allowed free access to the solid diet, the sucklings still have retarded body growth but do not develop paraplegia or grossly apparent vascular damage of the cerebellum. However, during the fourth week these animals exhibit a less severe form of "encephalopathy" consisting of hyperactivity, tremors, and stereotype behavior. Pair-fed controls coetaneous to experimental groups do not display such activities. There was no change in brain 5HT, GABA, or NE, but a 15-20% decrease in brain DA. Change in DA relative to other monoamines suggests a relationship between CNS dysfunction due to lead and DA metabolism in the brain.The experimental design as discribed provides a model of CNS dysfunction due to lead exposure without debilitating histopathologies. It is possible that our findings on increased motor activity and changes in brain dopamine may correspond to early responses to lead exposure before recognized overt signs of toxicity.
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PMID:Animal models of human disease: severe and mild lead encephalopathy in the neonatal rat. 483 Nov 41

Eleven observations of severe multicystic encephalopathy ( MCE ) in young infants and in a two-year-old child provide the basis for a summing-up and discussion of the various aspects of this characteristic polyetiologic phenomenon occurring in early infancy. In all cases the triggering causes or underlying disorders were different, although in five cases the common pathogenetic mechanism was a disturbance of circulation and/or respiration (acute respiratory distress syndrome). In two cases the basic disorders were a suppurative and a granulomatous meningoencephalitis. Carbon monoxide poisoning had occurred in one and diffuse meningocerebral angiomatosis in another two cases. In the eleventh case, one of a complicated twin birth, the exact cause of the MCE remained obscure. These cases together with those recorded in the literature demonstrate that the surprisingly constant pattern of damage in MCE , which results from different etiologic conditions, should be due to a specific mode of reaction of the infantile brain to a common pathogenetic mechanism. Anoxia with hypercapnia and the formation of brain edema are discussed as the basic events in the pathogenesis of MCE .
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PMID:Multicystic encephalopathy--a polyetiologic condition in early infancy: morphologic, pathogenetic and clinical aspects. 632 15

The most important complications of intravascular administration of contrast agents include idiosyncratic (anaphylactoid) reactions, shock, congestive heart failure, cardiac arrhythmias, acute renal failure, and neurotoxic effects. The incidence of serious neurotoxic effects is low. Entry of contrast agents into the central nervous system normally is limited but may be increased by osmotic opening of the blood-brain barrier with cerebral arteriography or arch aortography. Most neurotoxic effects are thought to represent direct effects of the contrast agent on brain or spinal cord. Adverse effects with arteriography include seizures, transient cortical blindness, brain edema, and spinal cord injury. Most cases of focal brain deficit (other than cortical blindness) are attributed to embolism secondary to the catheter. Seizures may occur with intravenous administration, especially in patients with brain tumors or other processes disrupting the blood-brain barrier. The most important adverse effects observed with myelographic agents include acute and chronic meningeal reactions with iophendylate, and seizures and transient encephalopathy with metrizamide.
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PMID:Neurotoxicity of radiological contrast agents. 634 33

Fulminant hepatic failure (FHF) is defined by the appearance of severe liver injury with hepatic encephalopathy in a previously healthy person. There are an estimated 2,000 cases of FHF in the United States yearly, representing 0.1% of all deaths and, perhaps, 6% of liver-related deaths. The causes of FHF are many, the chief ones in the United States being hepatitis A; B; non-A, non-B and drug induced liver disease. There are no specific therapies for FHF, however, liver transplantation is recommended for situations in which spontaneous recovery appears unlikely. Factors that are valuable in assessing the likelihood of spontaneous recovery are static features such as patient age and etiology of FHF and dynamic features including encephalopathy grade, prothrombin time, and serum bilirubin. Presently, approximately 7% of all liver transplants are done for FHF and the 1-year patient survival rates average 63%, somewhat less than survival rates for nonfulminant liver disease, averaging 78%. The management of patients with FHF is challenging, particularly important being monitoring and early treatment of infections, hemodynamic abnormalities, and brain edema. Innovative approaches to management and therapy include use of cytoprotective or antiviral medications, hepatic support systems, extracorporeal liver support, hepatocyte transplantation, auxiliary liver transplantation, and xenotransplantation. None of these are of proven benefit, but many are promising as a means to support the patient with FHF until spontaneous recovery occurs or a suitable liver graft is available for transplantation.
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PMID:Fulminant hepatic failure: summary of a workshop. 780 60

A clinico-neuropathological study was conducted on 60 cases of brain death, 36 males and 24 females, ranging in age from 11 to 81 years, the average being 49.4 years. Of these, 29 patients died of cerebrovascular disease. The average duration of brain death was 99 hours. The mean weight of the brain was 1466 g. Neuropathological findings were brain edema, congestion, herniation and various subarachnoid hemorrhages. Histologically, the cytoplasm of neurons was pale and ghost-like. In the white matter, myelin staining was pale, and nuclei of the glial cells were shrunken and piknotic. Autolysis of the cerebellar granular layer and the pituitary gland was evident in all cases. No reactive astrocytosis or infiltration of the cells in or around necrotic tissue could be seen. In eight cases, there was laminar infiltration of neutrophils in the superficial area of the cerebrum and brain stem, possibly due to temporary or partial recirculation. Correlation between the degree of autolysis and duration of brain death was observed, but no relationship between the degree of autolysis and the difference of underlying disease could be found. Autolysis in the cerebral cortex, thalamus, tegmentum of the brain stem, cerebellar granular layer and pituitary gland was most prominent. However, neuropathological diagnosis of underlying diseases could be made even in brain death. Histologically, the cases of brain death differed from those of cardiac arrest-induced encephalopathy and from those of long postmortem autopsy.
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PMID:A clinico-neuropathological study on brain death. 789 57

Hepatic encephalopathy (HE) is a serious neuropsychiatric complication of both acute and chronic liver disease. Several hypotheses have emerged following the development of appropriate animal models of HE and following studies using postmortem brain tissue from HE patients. It was originally suggested that primary energy failure was responsible for HE; however, there is now mounting evidence that the pathogenetic defect involves neurotransmission failure. Specific neurotransmitter systems implicated in the pathogenesis of portal-systemic encephalopathy (PSE) include the excitatory amino acid glutamate as well as neuroactive and/or neurotoxic biogenic amine metabolites. Although it has been proposed that alterations in the gamma-aminobutyric acid (GABA) system may play a pathogenic role in HE associated with both chronic and acute liver failure, there is now overwhelming evidence to the contrary. On the other hand, there is evidence to suggest that a subgroup of patients with HE have increased blood and CSF concentrations of substances that bind to GABA-related benzodiazepine receptors in brain. Alterations of both the glutamatergic and serotoninergic neurotransmitter systems in PSE likely result from the metabolic consequences of chronic exposure of brain to toxic levels of ammonia. In addition to its effects on glutamatergic and serotoninergic systems during chronic liver disease, ammonia has been intimately associated with the brain edema invariably observed in acute liver failure. It is evident that, regardless of the type of liver failure, effective reductions of ammonia levels remains the strategy of choice in the prevention of encephalopathy. The further elucidation of neurotransmitter alterations in HE could result in novel "downstream" neuropharmacologic approaches to its prevention and treatment.
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PMID:Current theories on the pathogenesis of hepatic encephalopathy. 791 20

A 19-year-old boy was admitted to our hospital because of impaired consciousness after experiencing fever and headaches for 7 days. The patient was in a deep coma or generalized convulsions, with retrocollis and decorticate posture. He never regained consciousness, remaining in an apallic state. The initial CSF pressure was 290 mm H2O, CSF cell count 18/3 mm3, protein 75 mg/100 ml, and sugar 74 mg/100 ml. There was no significant elevation in the viral titer in the serum or CSF. Plain CT on admission showed marked brain edema. MRI three months thereafter demonstrated symmetrical high intensity in the thalamus, the putamen and the cerebellum on both T1- and T2-weighted images, probably representing petechial bleeding. The lesions in the medial portion of the occipital lobes showed iso intensity on T1-weighted images and high intensity on T2-weighted images. These lesions were consistent with infarction of both posterior cerebral arteries, which may have been due to severe brain edema. The clinical and MRI findings were similar to those of patients with acute encephalopathy with low-density areas in the thalamus or bilateral striatal necrosis in childhood. To the best of our knowledge, there have been no reports of cases like ours in adults.
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PMID:[Acute encephalopathy with symmetrical lesions of the thalamus, the putamen and the cerebellum on magnetic resonance imaging]. 806 41

The clinical and pathological findings of two children diagnosed on autopsy with subacute necrotizing encephalopathy (SNE) are presented. One of the patients was a previously healthy 12-year-old boy with a rapid clinical course and fatal outcome. The second case was a mentally retarded 13-year-old girl with a positive family history of neurological disease and progressive deterioration. Brain edema, bilaterally symmetric gray-brown areas of spongy degeneration and cavity formation were present in the basal ganglia in both cases. A small cavity was noted in the right inferior olive in Case 2. Mamillary bodies were spared in both cases macroscopically and microscopically. Microscopic sections of the involved areas and the periaqueductal region in Case 2 exhibited variable degrees of necrosis, spongiosis with a striking proliferation, and dilatation of the capillaries. Similar changes were noted in the cerebral cortex of Case 1. Microglial and astrocytic proliferation with some loss of myelin were also noted. The neurons, although reduced in number, were frequently preserved within the lesions. To our knowledge, only three patients over two years old have been reported in the literature with an acute clinical course and a fatal outcome. Case 1 is the fourth such case.
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PMID:Subacute necrotizing encephalopathy (Leigh syndrome): report of two juvenile cases with fatal outcome. 819 9

We studied 18 formalin-fixed brains using MRI, and correlated our data with subsequent gross and microscopic examinations. 9 of our patients died from brain diseases (stroke due to infarction 4, stroke due to hemorrhage 1, encephalitis 2, head injury 1, brain tumor 1). 9 of our patients died from non-CNS diseases (stomach cancer 1, colon cancer 1, liver cirrhosis 1, myocardial infarction 2, trauma 4). In MRI of postmortem brain, T1WI and T 2WI was able to clearly show the myelination process of brainstem, basal ganglia, internal capsule and optic radiation in a 2 months-old-boy. The findings were similar to MRI of live infants. In normal adult postmortem brains, the T1WI showed a relatively low signal intensity of white matter as compared to gray matter. The pictures were similar to proton density images, not T1WI of normal adult brains. The reason why the signal intensity of the white matter was lower than the gray matter may have been due to lysis of lipid of myelin sheath in the formalin solution. Postmortem MRI was able to detect the periventricular hyperintensity (corresponding to arteriosclerotic encephalopathy) and subcortical hyperintensity spots (which corresponding to the widening of the Virchow-Robin perivascular space because of arteriosclerosis) in the brains of our elderly patients. Postmortem MRI detected the intracerebral hemorrhage, which appeared as a dark signal in both short and long TR images. However, MRI did not show blood in the ventricles, sulci, or superficial hemorrhages in the cortex of brain. Brain edema was revealed in the postmortem MRI and appeared as low signal intensity in T1WI and hyperintensity in T2WI. It was associated with a significant mass effect.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[MRI of postmortem brains]. 820 68

Eighteen term infants with hypoxic ischaemic encephalopathy (HIE) were studied with serial magnetic resonance imaging of the brain for up to two months following birth. Important early findings included brain swelling, cortical highlighting, diffuse loss of grey/white differentiation and loss of signal in the posterior limb of the internal capsule (PLIC). These signs were easier to identify on T1-weighted spin echo or inversion recovery sequences than on T2-weighted spin echo sequences. Brain swelling was only seen in the first seven days and was present in all grades of HIE. All other signs persisted and were associated with the subsequent development of major structural changes in the brain. The exact pattern of injury was best identified after the first week of life once the signs of brain swelling had cleared.
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PMID:Hypoxic ischaemic encephalopathy: early magnetic resonance imaging findings and their evolution. 854 56


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