1/4. 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 = 1keywords = metabolic disorder (Clic here for more details about this article) |
2/4. Neonatal seizures: the overlap between diagnosis of metabolic disorders and structural abnormalities. Case report.Inborn metabolic errors (IME) and cortical developmental malformations are uncommon etiologies of neonatal seizures, however they may represent treatable causes of refractory epilepsy and for this reason must be considered as possible etiological factors. This case report aims to demonstrate the importance of neuroimaging studies in one patient with neonatal seizures, even when there are clues pointing to a metabolic disorder. CASE REPORT: A previously healthy 14 day-old child started presenting reiterated focal motor seizures (FMS) which evolved to status epilepticus. Exams showed high serum levels of ammonia and no other abnormalities. A metabolic investigation was conducted with normal results. During follow-up, the patient presented developmental delay and left side hemiparesia. seizures remained controlled with anti-epileptic drugs for four months, followed by relapse with repetitive FMS on the left side. Temporary improvement was obtained with anti-epileptic drug adjustment. At the age of 6 months, during a new episode of status epilepticus, high ammonia levels were detected. Other metabolic exams remained normal. The child was referred to a video-electroencephalographic monitoring and continuous epileptiform discharges were recorded over the right parasagittal and midline regions, with predominance over the posterior quadrant. A new neuroimaging study was performed and displayed a malformation of cortical development. Our case illustrates that because newborns are prone to present metabolic disarrangement, an unbalance such as hyperammonemia may be a consequence of acute events and conduct to a misdiagnosis of IME.- - - - - - - - - - ranking = 5keywords = metabolic disorder (Clic here for more details about this article) |
3/4. Functional portal flow competition after auxiliary partial orthotopic living donor liver transplantation in noncirrhotic metabolic liver disease.Auxilliary partial orthotopic liver transplantation (APOLT) was introduced initially as a tentative or permanent support for patients with potentially reversible fulminant hepatic failure and has extended its indication to congenital metabolic disorder of the liver that has otherwise normal functional integrity. Postoperative management of APOLT is complicated because of functional portal flow competition between the native and graft liver. The native portal vein diversion to the graft is sometimes indicated to prevent functional competition; however, it is still an open question whether this technique can be theoretically indicated for APOLT patients. The authors report a on patient with ornithine transcarbamylase deficiency who received APOLT from a living donor without native portal vein diversion. Because of functional portal vein competition between the native and graft liver, the patient had to have portal vein diversion, portal vein embolization, and finally native hepatectomy to induce the graft regeneration after APOLT. After the experience of the current case, primary portal vein diversion for APOLT with noncirrhotic metabolic liver disease patients to prevent functional portal flow competition is recommended.- - - - - - - - - - ranking = 1keywords = metabolic disorder (Clic here for more details about this article) |
4/4. A novel R275X mutation of the SLC25A15 gene in a Japanese patient with the HHH syndrome.The hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome (MIM 238970) is an autosomal recessive metabolic disorder caused by a deficiency of the mitochondrial ornithine transporter, one of the urea cycle components. Mutations in the SLC25A15 gene have been coupled to the HHH syndrome. We describe a Japanese female patient with the HHH syndrome due to a novel homozygous R275X SLC25A15 mutation and male sibling who presumably carried the same mutation. He exhibited slowly progressive deterioration with seizures, a gait disturbance due to polyneuropathy, episodic confusion, and died of acute encephalopathy at 34 years of age while the proband exhibited moderate mental retardation, seizures, mild spastic paraplegia, and deafness without neurological deterioration for more than 20 years. The clinical features of previously documented patients with the homozygous SLC25A15 mutation demonstrated that genotype did not simply correlate with clinical severity. The phenotypic variability might depend on other factors, such as dietary and other genetic ones.- - - - - - - - - - ranking = 1keywords = metabolic disorder (Clic here for more details about this article) |