1/25. Successful use of alternate waste nitrogen agents and hemodialysis in a patient with hyperammonemic coma after heart-lung transplantation.BACKGROUND: Lethal hyperammonemic coma has been reported in 2 adults after lung transplantation. It was associated with a massive elevation of brain glutamine levels, while plasma glutamine levels were normal or only slightly elevated. In liver tissue, glutamine synthetase activity was markedly reduced, and the histologic findings resembled those of reye syndrome. The adequacy of therapy commonly used for inherited disorders of the urea cycle has not been adequately evaluated in patients with this form of secondary hyperammonemia. OBJECTIVE: To determine whether hemodialysis, in conjunction with intravenous sodium phenylacetate, sodium benzoate, and arginine hydrochloride therapy, would be efficacious in a patient with hyperammonemic coma after solid-organ transplantation. DESIGN: Case report. SETTING: A children's hospital. PATIENT: A 41-year-old woman with congenital heart disease developed a hyperammonemic coma with brain edema 19 days after undergoing a combined heart and lung transplantation. methods: Ammonium was measured in plasma. amino acids were quantitated in plasma and cerebrospinal fluid by column chromatography. The effectiveness of therapy was assessed by measuring plasma ammonium levels and intracranial pressure and performing sequential neurological examinations. RESULTS: The patient had the anomalous combination of increased cerebrospinal fluid and decreased plasma glutamine levels. To our knowledge, she is the first patient with this complication after solid-organ transplantation to survive after combined therapy with sodium phenylacetate, sodium benzoate, arginine hydrochloride, and hemodialysis. Complications of the acute coma included focal motor seizures, which were controlled with carbamazepine, and difficulty with short-term memory. CONCLUSIONS: The aggressive use of hemodialysis in conjunction with intravenous sodium phenylacetate, sodium benzoate, and arginine hydrochloride therapy may allow survival in patients after solid-organ transplantation. An acute acquired derangement in extra-central nervous system glutamine metabolism may play a role in the production of hyperammonemia in this illness that resembles reye syndrome, and, as in other hyperammonemic disorders, the duration and degree of elevation of brain glutamine levels may be the important determining factors in responsiveness to therapy.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
2/25. hyperammonemia in urea cycle disorders: role of the nephrologist.hyperammonemia associated with inherited disorders of amino acid and organic acid metabolism is usually manifested by irritability, somnolence, vomiting, seizures, and coma. Although the majority of these patients present in the newborn period, they may also present in childhood, adolescence, and adulthood with failure to thrive, persistent vomiting, developmental delay, or behavioral changes. Persistent hyperammonemia, if not treated rapidly, may cause irreversible neuronal damage. After the diagnosis of hyperammonemia is established in an acutely ill patient, certain diagnostic tests should be performed to differentiate between urea cycle defects and other causes of hyperammonemic encephalopathy. In a patient with a presumed inherited metabolic disorder, the aim of therapy should be to normalize blood ammonia levels. Recent experience has provided treatment guidelines that include minimizing endogenous ammonia production and protein catabolism, restricting nitrogen intake, administering substrates of the urea cycle, administering compounds that facilitate the removal of ammonia through alternative pathways, and, in severe cases, dialysis therapy. Initiation of dialysis in the encephalopathic patient with hyperammonemia is indicated if the ammonia blood level is greater than three to four times the upper limit of normal. Hemodialysis is the most effective treatment for rapidly reducing blood ammonia levels. Continuous hemofiltration and peritoneal dialysis are also effective modalities for reducing blood ammonia levels. An improved understanding of the metabolism of ammonia and neurological consequences of hyperammonemia will assist the nephrologist in providing optimal care for this high-risk patient population.- - - - - - - - - - ranking = 6keywords = cycle (Clic here for more details about this article) |
3/25. emergency treatment of neonatal hyperammonaemic coma with mild systemic hypothermia.An infant aged 3 days presented with hyperammonaemic coma and seizures, which were found to be a result of a urea-cycle defect. Haemofiltration, alternative pathway metabolites, and glucose and insulin failed to lower the plasma ammonia concentration below 2000 micromol/L. The infant was then cooled to a rectal temperature of 34 degrees C for 48 h and put on haemofiltration for 12 h. plasma ammonia fell to around 100 micromol/L and remained at this concentration after haemofiltration. He roused from his coma, breathed spontaneously, and resumed bottle feeding. hypothermia may be therapeutic in such instances of metabolic coma because it lowers the enzymatic rate of production of the toxin while non-enzymatic methods remove the toxin.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
4/25. Prognostic value of evoked potentials and sleep recordings in the prolonged comatose state of children. Preliminary data.OBJECTIVES: sleep recordings and evoked potentials (EPs) were used in five comatose children to evaluate their predictive value for outcome following a severe comatose state. methods AND SUBJECTS: The protocol included EEG, Brainstem Evoked Responses (BERs), Somatosensory evoked potentials (SEPs) and polysomnography. From 10 to 15 days post-coma (D10 to D15), EEG and clinical examinations were carried out every second day, then one day in four from 15 to 30 days post-coma (D15 to D30), and one day in seven from D30 to six months (M6). evoked potentials and polysomnography were recorded on D10-D15 or D30 in the second month (M2) and in M6. Of the five children, three were in anoxic coma and two in traumatic coma. All had extensive lesions and a glasgow coma scale (GCS) score of less than five. The results of the EEG, polysomnographic and EP recordings were compared to the clinical outcome. RESULTS AND CONCLUSION: In the three anoxic comas we observed BER abnormalities and the absence of SEP N20 associated with wide cortical lesions with brainstem extension. sleep recordings showed major alterations of the wake-sleep cycle without any improvement in M6. Abnormalities included loss of the normal REM-sleep pattern associated with alteration of NREM sleep and periods of increase in motor activity without EEG arousal. This sleep pattern appeared to be associated with involvement of the brainstem. In the two traumatic comas, alterations of the early cortical SEP responses were less severe and the BERs were normal. Some sleep spindles were observed as well as the persistence of sleep cycles in the first weeks post-coma. The combined use of EEG, EPs and polysomnography improved the outcome prediction in comparison with the use of just one modality. EPs and sleep recordings were far superior to clinical evaluation and to GCS in the appreciation of the functional status of comatose children. The reappearance of sleep patterns is considered to be of favorable prognosis for outcome of the coma state, as is the presence of sleep spindles in post-trauma coma. This study showed that EPs and sleep recordings help to further distinguish between patients with good or bad outcomes.- - - - - - - - - - ranking = 2keywords = cycle (Clic here for more details about this article) |
5/25. nature and nurture in vitamin B12 deficiency.We report on a child in whom severe nutritional vitamin B12 deficiency was exacerbated by a genetic impairment of the folate cycle, causing reduced CSF concentrations of the methyl group donor 5-methyltetrahydrofolate. Some patients with vitamin B12 deficiency may benefit from high dose folic acid supplementation, even if plasma concentrations are high.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
6/25. ammonia induced encephalopathy from valproic acid in a bipolar patient: case report.valproic acid is widely used as a mood stabilizer. We report a case of an adult with bipolar disorder taking therapeutic doses of valproic acid, who presented to the emergency department with coma related to hyperammonemia as a complication of valproic acid treatment. valproic acid was discontinued which resulted in rapid clinical recovery. valproic acid induced coma was likely related to a urea cycle enzymopathy. Clinicians should consider hyperammonemia in all patients who present with coma and other mental status changes while on valproic acid. In such patients, ammonia level should be obtained in addition to liver function tests.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
7/25. carbamyl phosphate synthetase-1 deficiency discovered after valproic acid-induced coma.valproic acid induced coma is presented in an adult patient without a history of metabolic disease. Liver biopsy revealed a reduction in activity of carbamyl phosphate synthetase-I, an enzyme obligated for transformation of ammonia to urea in the urea cycle. After recovery CT scan follow-up showed marked cerebral atrophy which did not exist prior to the state of coma. risk factors are discussed.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
8/25. Reversible coma secondary to cefepime neurotoxicity.OBJECTIVE: To describe a case of cefepime neurotoxicity associated with acute renal failure that resulted in nonconvulsive status epilepticus. CASE SUMMARY: A 66-year-old woman with acute myeloid leukemia had fever on the third day of the initial chemotherapy cycle. Empiric antibiotic treatment with cefepime 2 g every 8 hours was started; fluconazole and vancomycin were subsequently added due to the persistence of fever. Ten days after initiation of cefepime, the patient developed acute renal failure followed by altered consciousness (glasgow coma scale 6) associated with nonconvulsive status epilepticus. Cefepime was discontinued. Epileptiform activity in the electroencephalogram disappeared with clonazepam, and the patient regained consciousness 48 hours after cefepime withdrawal. DISCUSSION: Acute renal impairment combined with the use of cefepime may account for nonconvulsive status epilepticus. An objective causality assessment revealed that the adverse event was probably due to cefepime. Cefepime's neurotoxic effects derive from high serum concentrations resulting from decreased renal clearance, increased unbound antibiotic, and blood-brain barrier dysfunction during uremia. CONCLUSIONS: The combination of cefepime treatment and acute renal failure may induce drug-related neurotoxicity. Nonconvulsive status epilepticus frequently passes unnoticed in severely ill patients without a history of epilepsy. This disorder should be included in the list of potential causes of coma. In this patient, early detection of nonconvulsive status epilepticus and withdrawal of the antibiotic resulted in full recovery.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
9/25. Treatment of self-inflicted oral trauma in a comatose patient: a case report.Trauma to oral soft tissues in comatose patients may be more widespread than reported, as no extensive study of this problem has been conducted. Various appliances for the prevention of self-inflicted injuries to oral tissues particularly in children and the physically and mentally challenged have been documented, but there is little information on their use in adult comatose patients.Because comatose patients lack cerebral control of the masticatory cycle, they can easily injure themselves. Although it is not uncommon for patients with a decreased level of consciousness and in need of intensive care to be restrained to prevent injury due to involuntary movement of the limbs, head and neck restraint is often difficult and may be dangerous to the patient. This case report presents a simple solution to the problem of self-inflicted trauma to oral tissues.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
10/25. Acute hyperammonemic coma with chronic valproic acid therapy.OBJECTIVE: To report a case of dose-related hyperammonemic coma without liver failure in a patient receiving chronic valproate therapy. CASE SUMMARY: A 56-year-old woman with poorly controlled epilepsy, receiving valproate at subtherapeutic levels for 6 years, developed a life-threatening hyperammonemic coma following a moderate dosage increase. DISCUSSION: Hyperammonemic coma without associated liver failure is an extremely rare complication of valproate therapy, described primarily in patients with inborn errors of metabolism and occurring idiosyncratically during initial stages of therapy. In our case, family history was suggestive of an X-linked disorder, raising the possibility that our patient may have been an asymptomatic carrier of a urea cycle enzyme deficiency unmasked by valproate therapy. To our knowledge, as of October 24, 2005, only one prior case of hyperammonemic coma in the context of chronic valproate monotherapy has been described. Application of the Naranjo probability scale score suggests that a causal relationship between valproic acid and hyperammonemic coma was probable. CONCLUSIONS: The widespread use of valproic acid emphasizes the need to maintain a high degree of suspicion with respect to this rare but potentially fatal adverse effect at all times, regardless of therapy duration.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
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