Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ornithine transcarbamylase deficiency is an X-linked disorder of the urea cycle that can cause hyperammonemic encephalopathy in hemizygous males and heterozygous females. Affected females typically limit protein intake in their diet. This case report describes a 36-year-old woman with ulcerative colitis who went into hyperammonemic coma after administration of total parenteral nutrition. A similar episode of coma had occurred 7 years earlier after she delivered a normal boy. Heterozygous ornithine transcarbamylase deficiency was diagnosed based on a positive allopurinol tolerance test result after elevated levels of plasma glutamine and low plasma citrulline were detected. The protein load associated with parenteral alimentation resulted in symptomatic expression of this partial enzyme deficiency in this unique case. Partial ornithine transcarbamylase deficiency must always be considered in adult women and men with hyperammonemia who have normal liver function test results.
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PMID:Hyperammonemic coma due to parenteral nutrition in a woman with heterozygous ornithine transcarbamylase deficiency. 779 25

Hyperammonemic encephalopathy has occasionally been reported in uremic patients receiving hyperalimentation with essential amino acid (EAA) as a source of nitrogen as one of the remaining treatment options when the enteric routes were prohibited. We encountered this complication in a patient with normal renal function. A rat animal model was designed to elucidate the mechanism of hyperammonemia resulting from hyperalimentation with EAA as a source of nitrogen. Sixty-four male Long-Evan rats were divided into eight groups receiving feeds ad libitum or different formula of hyperalimentation. Hyperammonemia was found in every rat given hyperalimentation with EAA as the only nitrogen source. Using the Tukey honestly significant difference test, the results were significantly higher (p < 0.001) than that of the control group which were given feeds ad libitum and those groups given hyperalimentation for the same number of days but with mixed amino acid (MAA) as the nitrogen source. Adding arginine to EAA for a further four days after initial administration of EAA hyperalimentation for three days only slightly lowered the mean serum ammonia level. When compared to that of the three-day EAA hyperalimentation group, the difference was not statistically significant. Adding arginine, citrulline, and ornithine to EAA for a further four days significantly lowered the mean serum ammonia level. When we changed EAA hyperalimentation to MAA hyperalimentation for a further four days, the mean serum ammonia level decreased dramatically to nearly normal. Hyperalimentation using EAA as the exclusive source of nitrogen resulted in hyperammonemia. A deficiency of arginine or other amino acids of the urea cycle failed to account completely for the hyperammonemia observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hyperammonemic encephalopathy due to essential amino acid hyperalimentation. 785 37

Hemolytic uremic syndrome (HUS) is defined as microangiopathic hemolytic anemia, thrombocytopenia and uremia. It is an important cause of acute renal failure (ARF) in children all over the world. The present study was carried out to assess the incidence, clinical presentation, hematological and biochemical profile of children presenting with HUS from 1987 to 1990. Out of the 100 cases who presented with ARF 22 had HUS. A majority of these children were males below 1 year of age, and had a prodromal phase of mainly gastrointestinal manifestations lasting for about a week. Anemia was a constant feature followed by bleeding diathesis, mainly melena and purpura. Neurological manifestations included altered sensorium, irritability, coma, hypertensive encephalopathy and convulsions. Renal problems mainly included oliguria, hypertension, hematuria and edema. Investigations revealed thrombocytopenia and microangiopathic hemolytic anemia in all cases. Evidence of disseminated intravascular coagulation (DIC) was observed in 3 cases as decreased fibrinogen levels, increased fibrinogen degradation products and deranged clotting studies. Blood biochemistry revealed azotemia in all cases, hyponatremia in 5 cases, hypernatremia in 3 cases and hyperkalemia in 12 cases. Stool culture showed the presence of Shigella in 8, E. coli in 6 and Klebsiella in 4 cases. Out of 22 cases of HUS, 15 were treated conservatively; of these 2 died. Both of these deaths were due to DIC 7 children were put on peritoneal dialysis; only 1 child died in this group. Factors affecting the outcome were duration of oliguria, levels of blood urea and presence of encephalopathy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A clinico-hematological profile of hemolytic-uremic syndrome. 788 99

Urease is an enzyme found in plants and bacteria, but not mammals. It catalyzes the conversion of urea to carbon dioxide and ammonia. Ammonia shortens the life span of cells; and higher concentrations cause tissue necrosis and cytolysis. Twenty percent of total body urea is converted to ammonia by bacterial urease in the colon. Small injections of urease immunize animals by producing antiurease, a gamma globulin, which inactivates urease. Immunization eliminates the colonic conversion of urea to ammonia. Injection of urease produces ammonia intoxication making immunization hazardous. Although previously impossible, a non enzymatic urease antigen was synthesized by covalently bonding jack bean urease with glutaraldehyde. This antigen stimulated the production of antiurease that inactivates native urease. Helicobacter pylori, a potent urease producer, has been implicated in peptic ulcer, gastritis and other inflammatory bowel lesions. The pathogenicity of H pylori is dependent on its urease production. Immunization to urease can render H pylori non pathogenic. Cirrhotics develop encephalopathy and hyperammonemia because their livers fail to convert all the ammonia in portal venous blood to urea and collaterals develop by passing the liver. Colonic ammonia increases the turnover rate of colonic mucosa. Ammonia absorbed into the portal venous system is transported to the liver where it is reconverted to urea. Absorbed ammonia adversely influences liver function. Infections with urease producing organisms destroy the renal parenchyma and produce struvite stones. Urease immunization aids colonic healing and prevents uremic colitis. Absorbed ammonia is a noxious influence on the liver. Animals immunized to urease regenerate the liver faster and are less susceptible to hepatotoxins. Immunization to urease ameliorates cirrhosis. Proteus and other urease producers become non toxic and do not damage the renal parenchyma. Urease is responsible for the pathogenicity of infections with urease producing organisms. Immunization to urease renders urease producing organisms non pathogenic.
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PMID:Awakenings to the pathogenicity of urease and the requirement for continuous long term therapy. 799 80

There were 101 (4.6%) cases of malignant and accelerated hypertension among 2195 hypertensives patients treated in Department of Hypertension of National Institute of Cardiology between 1981 and 1990. Almost 30% of these patients were diagnosed as having secondary cause of hypertension. Comparison with control group of patients with moderate or mild hypertension revealed that malignant hypertensives had a shorter history of illness, lower level of education, higher evidence of smoking and over-consumption of alcohol. The systolic and diastolic blood pressure values were significantly higher in this group. The patients with malignant hypertension had significantly higher blood concentration of urea, creatinine and uric acid. Mild anemia was also present. Severe cardiovascular complications (myocardial infarction, stroke, encephalopathy, left ventricular failure) were observed in 44% cases of malignant hypertension. Due to efficacious hypotensive treatment blood pressure decreased significantly and biochemical indicators of renal function improved. Withdrawal of characteristic for malignant hypertension changes in fundoscopy was also observed. Results of this study indicate that prompt and aggressive treatment with normalization of blood pressure results in reversal of vascular lesions and permits recovery of cerebral and renal function.
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PMID:[Accelerated and malignant hypertension--clinical observation]. 802 29

Acute glomerulonephritis (AGN) remains fairly common in the developing world although its frequency has declined in the industrial countries. The pattern of AGN was studied in one hundred hospitalised children. We recorded an increased prevalence in school age, i.e., 6-15 years (75%) and the occurrence of a streptococcal infection (90%), most often a pharyngeal infection (86%), one to three weeks preceding the illness. The problems that needed specific management during the acute phase were hypertension (39%), encephalopathy (5%) and ARF with hyperkalemia, 2% of the patients needing haemodialysis. Most of our patients (98%) recovered with 2% progressing to RPGN. The excellent prognosis of AGN with proper management emphasises the need for optimal care during the acute phase in the hospitalised children.
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PMID:Acute glomerulonephritis in children. 807 77

Hyperammonemia is a recognized side effect of treatment with the antiepileptic drug (AED) valproate (VPA). Encephalopathic complications have also been observed in some patients receiving VPA therapy. The relation between VPA-induced hyperammonemia and encephalopathy is not clear, however. A model of ammonium (NH4+)-induced coma was used to investigate the contribution of VPA and to assess the efficacy of citrulline (a urea cycle intermediate) on hyperammonemia and encephalopathy. In groups of 6-12 rats, administration of VPA (2.5 mmol/kg) was associated with (a) a decrease in the dose of NH4+ that produces coma in 50% of the animals (CD5) from 6.1 to 3.6 mmol/kg, and (b) significant increases in blood ammonia concentrations in NH(4+)-treated animals. In addition, clear evidence also showed that in the presence of VPA, a lesser concentration of ammonia produced coma. Citrulline treatment (5.0 mmol/kg) was associated with (a) an increase in the CD50 value of NH(4+)-treated animals from 6.1 to 8.6 mmol/kg, (b) a statistically significant decrease in ammonia concentration at all doses examined, (c) complete protection from encephalopathic effects of NH4+ at citrulline concentrations three- to tenfold greater than basal levels; and (d) a 24% increase in the CD50 value and a statistically significant decrease in ammonia concentration of VPA/NH(4+)-treated animals. These findings indicate that VPA has a dual effect on encephalopathy and that citrulline should benefit those patients treated with VPA who experience adverse encephalopathic effects.
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PMID:Effects of valproate and citrulline on ammonium-induced encephalopathy. 811 41

To evaluate the presence and the severity of uraemic encephalopathy (UE) in regular dialysis treatment patients in relation to dialytic age, pattern reversal visual evoked potentials (PRVEPs) and brainstem auditory evoked potentials (BAEPs) were respectively performed in 86 and 98 patients on haemodialysis for 1-194 months, divided into three subgroups according to dialytic age (group 1, < 5 years of regular dialysis; group 2, 5-10 years; group 3, > 10 years). VEPs in the whole group of 86 patients and in each subgroup with different dialytic age differed significantly from controls for both eyes, 41.7% of whom had pathological P100; no differences were observed between the three subgroups. BAEPs were pathological in 9.7% of the ears and 18.4% of patients. On the right ear the three subgroups were significantly different from controls in the latencies of peaks III and V; subgroup 2 and 3 differed from controls in the I-V interpeak, while the interpeak I-III was different from controls only in subgroup 3. On the left ear the three subgroups differed significantly from controls in the latencies of peak V; subgroup 2 and 3 were significantly different from controls in the latency of peak I; subgroup 3 was different in the peak III latency; subgroup 1 and 3 were different from controls in the interpeak I-V; no differences were observed in BAEPs between the three subgroups with increasing dialytic age. No significant correlations were found between the neurophysiological parameters and some biochemical parameters (urea, creatinine, PTH).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evoked potentials (VEPs and BAEPs) in a large cohort of short- and long-term haemodialysed patients. 827 27

A three compartment mathematical model was used to analyse the urea response to an alanine infusion in six control subjects, and in 15 patients with liver cirrhosis and variable degree of hepatocellular failure. Model-derived coefficients were used to calculate two parameters (Ymax and Tmax), able to describe the theoretical response of the conversion of amino acid derived nitrogen into urea, in response to a unit impulse in alanine concentration. They correspond to the maximum rate of conversion of nitrogen from an intermediary pool into urea and to the time delay between the impulse and Ymax, respectively. In cirrhosis, the apparent volume of distribution of infused alanine was smaller than in controls, while the conversion of alanine nitrogen into an intermediary pool of nitrogen and finally into urea nitrogen were both reduced. Also Ymax was reduced by 50% in cirrhosis, whereas Tmax was increased by 50%, and both significantly correlated with galactose elimination capacity (GEC; R2 = 0.706 and R2 = 0.505, respectively) and with antipyrine clearance (Ap Cl; R2 = 0.823 and R2 = 0.576, respectively). Model-derived assessment of urea appearance in response to alanine infusion is able to quantify the functional liver cell mass, and may prove useful for the study of nitrogen metabolism in cirrhosis, mainly in relation to encephalopathy.
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PMID:Model-derived assessment of urea appearance in response to alanine infusion: a quantitative measure of liver function in cirrhosis. 828 Aug 43

The present report describes a rare of a 77-year-old woman who developed encephalopathy and metabolic acidosis associated with hyperammonemia, at the introduction of hemodialysis by chronic renal failure. With the intravenous infusion of HCO3-, levels of acidosis and hyperammonemia decreased rapidly. Concomitantly the disturbance of consciousness was improved. Results of plasma amino acid patterns of pre and post infusion of HCO3- showed improvement of the metabolism of the urea cycle, increased urea synthesis and decreased plasma ammonium levels. The role of the hepatic urea cycle has been considered to be exclusively the elimination of potentially toxic ammonia. In the conventional view, the acid base balance of the body obtains stabilized homeostasis by the function of the principal organs, lungs and kidneys. But, it has been recently shown that urea cycle is an important factor in the maintenance of pH homeostasis, due to regulated metabolism of HCO3-. Both HCO3- and NH4+ are converted to urea indicating the urea cycle's involvement in acid base homeostasis. 2HCO3- + 2NH4+-->urea+CO2+3H2O In this case, with the infusion of HCO3, the metabolism of the urea-cycle was improved and plasma ammonium levels were decreased. This indicates that HCO3- is an important factor for the metabolism of ammonia.
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PMID:[A case of hyperammonemia in chronic renal failure successfully treated with the infusion of NaHCO3]. 841 69


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