Manejo inicial de la hiperamonemia aguda en pediatría / Initial management of acute hyperammonemia in pediatrics

La hiperamonemia constituye una emergencia médica. No existen publicaciones que hagan referencia a la disponibilidad de recursos, insumos y conocimientos necesarios para el manejo inicial de esta por parte del pediatra en nuestro país, pero, según la experiencia de los autores, los recursos necesarios no se encuentran disponibles los 365 días del año en una gran porción de nuestro territorio. Sobre la base de este estado de situación, de una revisión bibliográfica internacional sobre el tema y de la experiencia de los autores, se elaboraron una serie de recomendaciones para el manejo pediátrico inicial de esta emergencia, que tienen como objetivo poder reducir las deficiencias, permitir una sospecha clínica adecuada que lleve a un diagnóstico y tratamiento de emergencia oportunos, con utilización racional de recursos farmacológicos (algunos de ellos de alto costo), para reducir la morbimortalidad que asocia la patología.

Hyperammonemia is a medical emergency. There are no publications regarding the availability of resources, supplies, and knowledge necessary for the initial management of hyperammonemia by pediatricians in Argentina; however, according to the authors' experience, the necessary resources are not available all year round in a large portion of our territory. Based on such state of affairs, an international bibliographic review on this topic and the authors' experience, we developed a series of recommendations for the initial pediatric management of this emergency, with the objective of reducing deficiencies, allowing adequate clinical suspicion leading to a timely diagnosis and emergency management and a rational use of pharmacological resources (some of which are costly) to reduce the morbidity and mortality associated with hyperammonemia.

Medical nutrition management and follow-up of patients with late-onset ornithine transcarbamylase deficiency / 中华实用儿科临床杂志

Objective:To explore the clinical characteristics and medical nutritional therapy of 6 patients with late-onset ornithine transcarbamylase (OTC) deficiency.Methods:The clinical features, biochemical data, gene variations and treatment outcomes of 6 children with late-onset OTC deficiency admitted to the Department of Clinical Nutrition, Children′s Hospital of Nanjing Medical University from January 2020 to April 2022 were retrospectively analyzed.The 6 patients were all intervened by a long-term medical nutrition management.Results:Liver dysfunction and hyperammonemia (172.1-348.0 μmol/L) were found in all the 6 children with late-onset OTC deficiency.Serum citrulline decreased in 3 patients (3.95-5.43 μmol/L). Three patients showed increased urine orotic acid (123.48-342.60 mmol/mol Cr). Urine uracil increased in 4 patients (106.77-1 207.26 mmol/mol Cr). Variations of the OTC gene [c.364G>C p. (E122Q), c.1028C>G p. (T343R), c.664-2(IVS6)A>C, c.635G>T p. (G212V), c.929_c.931delAAG p. (E310del), c.829C>T p. (R277W)] were identified in all patients.The 6 children were all managed by individualized medical nutrition program and followed up for a long time.During the follow-up period, 3 cases developed hypoproteinemia, acute metabolic crisis and growth retardation, 3 cases had normal growth and laboratory indicators, and 1 case received liver transplantation after 3 months of nutritional management. Conclusions:The clinical manifestations of OTC deficiency are non-specific.Blood amino acids, urine organic acids and genetic tests are important for the diagnosis.Long-term regular medical nutrition management is helpful to improve the prognosis and quality of life of children.

Expert consensus on the diagnosis and treatment of neonatal hyperammonemia / 中国当代儿科杂志

Neonatal hyperammonemia is a disorder of ammonia metabolism that occurs in the neonatal period. It is a clinical syndrome characterized by abnormal accumulation of ammonia in the blood and dysfunction of the central nervous system. Due to its low incidence and lack of specificity in clinical manifestations, it is easy to cause misdiagnosis and missed diagnosis. In order to further standardize the diagnosis and treatment of neonatal hyperammonemia, the Youth Commission, Subspecialty Group of Neonatology, Society of Pediatrics, Chinese Medical Association formulated the expert consensus based on clinical evidence in China and overseas and combined with clinical practice experience,and put forward 18 recommendations for the diagnosis and treatment of neonatal hyperaminemia.

Neonate-onset ornithine transcarbamylase deficiency / 中国当代儿科杂志

The male neonate in this case study was admitted to the hospital at 15 hours of age due to respiratory distress for 15 hours and poor response for 3 hours after resuscitation from asphyxia. The neonate was highly unresponsive, with central respiratory failure and seizures. Serum ammonia was elevated (>1 000 μmol/L). Blood tandem mass spectrometry revealed a significant decrease in citrulline. Rapid familial whole genome sequencing revealed OTC gene mutations inherited from the mother. Continuous hemodialysis filtration and other treatments were given. Neurological assessment was performed by cranial magnetic resonance imaging and electroencephalogram. The neonate was diagnosed with ornithine transcarbamylase deficiency combined with brain injury. He died at 6 days of age after withdrawing care. This article focuses on the differential diagnosis of neonatal hyperammonemia and introduces the multidisciplinary management of inborn error of metabolism.

Value of blood ammonia and cholinesterase in the early diagnosis of liver cirrhosis with minimal hepatic encephalopathy / 临床肝胆病杂志

Objective To investigate the value of serum markers in the early diagnosis of liver cirrhosis with minimal hepatic encephalopathy (MHE). Methods A prospective analysis was performed for 81 patients who were hospitalized and treated in General Hospital of Ningxia Medical University from April 2020 to February 2022, and all these patients were diagnosed with hepatitis B cirrhosis based on clinical manifestation, laboratory examination, and radiological examination or liver biopsy. According to digital connection test A (NCT-A) and digital symbol test (DST), these patients were divided into simple cirrhosis group with 45 patients and MHE group with 36 patients. Related indices were measured, including liver function [alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), and total bilirubin (TBil)], albumin, blood ammonia, cholinesterase, and prothrombin time. The independent samples t -test was used for comparison of normally distributed continuous data between two groups; the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups, and the Kruskal-Wallis H test was used for comparison between multiple groups; the chi-square test was used for comparison of categorical data between groups. The logistic regression analysis and the area under the ROC curve (AUC) were used to investigate the predictive factors for MHE. Results Compared with the simple cirrhosis group, the MHE group had a significant increase in NCT-A score ( Z =-7.110, P < 0.001) and a significant reduction in DST score ( t =12.223, P < 0.001). The univariate analysis showed that there were significant changes in AST, albumin, prothrombin time, cholinesterase, and blood ammonia in the patients with MHE ( Z =-2.319, -2.643, -1.982, -6.594, and -5.331, all P < 0.05), while the multivariate analysis showed that only cholinesterase and blood ammonia were significant predictive factors (all P < 0.05) and were correlated with Child-Pugh score (all P < 0.05). Cholinesterase, blood ammonia, and their combination had an AUC of 0.925, 0.845, and 0.941, respectively, in the diagnosis of MHE, with an optimal cut-off value of 2966, 60, and 0.513, respectively. Conclusion Blood ammonia, cholinesterase, and their combined measurement have a potential clinical value in the early diagnosis of liver cirrhosis with MHE.

Severe neonatal transient hyperammonemia: a report of two cases and literature review / 中华围产医学杂志

Objective:To investigate the clinical features, treatment, and prognosis of transient hyperammonemia of the newborn (THAN).Methods:Data of two infants with severe THAN admitted to the Department of Neonatology of Shanghai Children's Hospital in September 2021 and August 2022 were retrospectively investigated. Clinical data of confirmed THAN cases (blood ammonia>400 μmol/L) were collected from relevant literature retrieved from the Wanfang Database, China National Knowledge Infrastructure, Chinese Medical Journal Database, and PubMed up to July 2022. A descriptive method was used for statistical analysis.Results:A total of 24 cases were involved (two in the present study, and 22 in 12 retrieved articles), including 19 (79.2%) premature newborns and five term infants. The average birth weight was (2 237±608) g and the average onset time was 27 h (4-55 h) after birth. The early clinical symptoms included respiratory distress and hyporesponsiveness (drowsiness, lethargy, coma or hypotonia) in 18 cases (75.0%), metabolic acidosis in 11 cases (45.8%), hypocalcemia in seven cases (29.2%), pupil fixation/dilation in six cases (25.0%), convulsion in five cases (20.8%), apnea in three cases (12.5%) and sinus bradycardia in one case (4.2%). The serum ammonia levels were 1 422.8 μmol/L (547.2-4 494.1 μmol/L). Treatments included peritoneal dialysis plus exchange transfusion in eight cases (33.3%), exchange transfusion in seven cases (29.2%), continuous renal replacement therapy (CRRT) in four cases (16.7%), arginine in two cases (8.3%), peritoneal dialysis in two cases (8.3%), and CRRT+peritoneal dialysis in one case (4.2%). During follow-ups of four months (one month to six years), 13 cases (54.2%) showed no abnormalities in development; two (8.3%) had a neurodevelopmental delay, and six (25.0%) died. The follow-up of the other three cases (12.5%) were not reported in the literature.Conclusions:The early clinical manifestation of severe THAN is atypical. A good prognosis can be expected through early exclusion of possible hyperammonemia-related genetic metabolic diseases and lowering the serum ammonia level. Long-term follow-up is needed for neurological evaluation.

Persistent neonatal hypoglycemia secondary to hyperinsulinism/hyperammonemia. Case report

Introduction: Hyperinsulinism/hyperammonemia syndrome (HI/HA) is a rare genetic disease caused by the activation of mutations in the GLUD1 gene. It is characterized by recurrent symptomatic hypoglycemic episodes, poor tolerance to fasting, and requirement for high metabolic fluxes of glucose, with an insulin/ glucose ratio ≥0.3. Case presentation: Preterm male newborn (36 2/7 weeks of gestation) who was delivered by caesarean section due to acute fetal distress. At birth, the patient presented with weak cry, hypotonia, mild respiratory distress, and recurrent episodes of hypoglycemia, thus 10% dextrose and hydrocortisone were administered initially. Treatment with octeoctride was started, but due to the patient's poor response, laboratory tests were performed, reporting the following findings: serum ammonia: 137.6, insulin: 39.1 µIU/mL, blood glucose: 26.06 mg/dL, and insulin/blood glucose ratio: 1.5, leading to the diagnosis of HI/HA syndrome. Treatment with diazoxide was initiated, achieving a progressive improvement in blood glucose levels; however, afterwards, he presented seizures, so midazolam, phenobarbital and valproic acid were added to the treatment regimen. When hypoglycemia and seizure episodes resolved, the patient was discharged at 2 months and 5 days of life, and a treatment based on oral administration of diazoxide, phenobarbital and valproic acid was prescribed. Conclusion: HI/HA syndrome is characterized by recurrent episodes of hypoglycemia and hyperammonemia; therefore, the presence of these two conditions in neonates is highly suggestive of the disease. Timely diagnosis and treatment are required to avoid neurological sequelae, and transdisciplinary assessment is of great importance, as it increases the likelihood of early diagnosis and timely administration of diazoxide to restore normal glucose levels.

Introducción. El síndrome hiperinsulinismo/hiperamoniemia (HI/HA) es una enfermedad genética rara causada por la activación de mutaciones en el gen GLUD1. Este síndrome se caracteriza por hipoglucemias sintomáticas recurrentes, poca tolerancia al ayuno y requerimiento de altos flujos metabólicos de glucosa, con un índice insulina/glucosa ≥0.3. Presentación del caso. Recién nacido masculino pretérmino de 36 2/7 semanas de gestación que nació por cesárea debido a sufrimiento fetal agudo. Al nacer, el paciente presentó llanto débil, hipotonia, dificultad respiratoria leve y episodios recurrentes de hipoglicemia, por lo que inicialmente se administró dextrosa 10% e hidrocortisona. Se inició tratamiento con octeoctride, pero ante la pobre respuesta, se realizaron exámenes de laboratorio en los que se reportó lo siguiente: amonio sérico: 137.6 pmol/L, insulina: 39.1 µUl/mL, glucemia: 26.06 mg/dL y relación insulina/glucemia: 1.5, lo que permitió diagnosticarlo con síndrome HI/HA. Se inició tratamiento con diazóxido, lográndose mejora progresiva de la glicemia; pero posteriormente presentó crisis convulsivas, por lo que se agregó midazolam, fenobarbital y ácido valproico al tratamiento. Al resolver la hipoglicemia y las convulsiones, el paciente fue dado de alta a los 2 meses y 5 días de vida, prescribiéndose un tratamiento basado en la administración oral de diazóxido, fenobarbital y ácido valproico. Conclusión. El síndrome HI/HA se caracteriza por hipoglucemias recurrentes e hiperamoniemia; por tanto, la presencia de estas dos condiciones en neonatos es altamente sugestiva de la enfermedad. Su diagnóstico y tratamiento deben ser oportunos para evitar secuelas neurológicas, siendo la valoración transdisciplinaria de gran importancia, pues aumenta las probabilidades de un diagnóstico temprano y administración oportuna de diazóxido para restablecer los niveles normales de glucosa.

Córnea plana congénita y error innato del metabolismo en un niño

Introducción: La córnea plana congénita es una rara anomalía de herencia autosómica dominante o recesiva. Los defectos del ciclo de la urea son errores innatos del metabolismo que puede producir encefalopatía progresiva. Objetivo: Describir las características clínicas de un paciente con diagnósticos de córnea plana congénita y error innato del metabolismo. Presentación del caso: Paciente masculino de 7 años de edad, miembro de la cuarta generación de una familia con diagnóstico de córnea plana congénita. Al examen oftalmológico se observó en ambos ojos esclerización superior del limbo, aplanamiento corneal generalizado y cámaras anteriores estrechas. La topografía corneal mostró patrones esféricos y aplanamiento corneal más prominente en la media y extrema periferia. A la edad de 5 años comenzó a presentar ataxia recurrente, crisis epilépticas de inicio focal motoras clónicas en el hemicuerpo derecho y vómitos. Ingresó en estado de coma en la unidad de cuidados intensivos pediátricos del Hospital Pediátrico Universitario "William Soler". Se planteó encefalopatía progresiva por trastorno en el ciclo de la urea luego de constatarse hiperamonemia (error congénito del metabolismo), sin acidosis metabólica. Conclusiones: La córnea plana congénita es una enfermedad caracterizada por aplanamiento corneal generalizado con repercusión en la calidad visual. Los errores innatos del metabolismo debidos a trastornos en el ciclo de la urea se caracterizan por manifestaciones neurológicas graves con peligro potencial para la vida. Resulta novedosa la presentación de estas dos enfermedades infrecuentes en un mismo paciente, asociación que no aparece publicada con anterioridad.

Introduction: Congenital flat cornea is a rare anomaly of dominant or recessive autosomal inheritance. Urea cycle defects are inborn errors of metabolism that can lead to progressive encephalopathy. Objective: To describe the clinical characteristics of a patient with diagnoses of congenital flat cornea and inborn error of metabolism. Case Presentation: A 7-year-old male patient, member of the fourth generation of a family diagnosed with congenital flat cornea. Ophthalmological examination showed upper limbal sclerization, generalized corneal flattening and narrow anterior chambers in both eyes. Corneal topography showed more prominent spherical patterns and corneal flattening in the middle and extreme periphery. At the age of 5 years, he began to present recurrent ataxia, focal onset epileptic seizures of clonic motor in the right hemibody and vomiting. He was admitted in a coma in the pediatric intensive care unit of "William Soler" University Pediatric Hospital. Progressive encephalopathy was stated due to disorder in the urea cycle after hyperammonemia (congenital error of metabolism) was observed, without metabolic acidosis. Conclusions: Congenital flat cornea is a disease characterized by generalized corneal flattening with an impact on visual quality. Inborn errors of metabolism due to disorders in the urea cycle are characterized by severe neurological manifestations with potential danger to life. The presentation of these two rare diseases in the same patient is novel; an association that has not been published previously.

Encefalopatia hiperamonêmica associada ao valproato na hemorragia subaracnóidea: um diagnóstico a considerar / Valproate-associated hyperammonemic encephalopathy in subarachnoid hemorrhage: a diagnosis to consider

RESUMO Objetivo: A hemorragia subaracnóidea é uma doença prevalente com alta morbidade e mortalidade. Inúmeras complicações contribuem para a lesão cerebral e desafiam o médico no diagnóstico e tratamento. A encefalopatia hiperamonêmica associada ao valproato é uma entidade rara, subdiagnosticada, grave e importante a ser considerada. Apresentamos o caso de um paciente com hemorragia subaracnóidea que recebeu profilaxia anticonvulsivante com valproato e evoluiu com piora neurológica associada a níveis plasmáticos elevados de amônia e descargas periódicas no eletroencefalograma, sem outras causas identificáveis. A interrupção do tratamento com ácido valproico e a normalização dos níveis plasmáticos de amônia resultaram em melhora do quadro neurológico e eletroencefalográfico.

ABSTRACT Objective: Subarachnoid hemorrhage is a prevalent disease with high morbidity and mortality. Numerous complications contribute to brain injury and defy the clinical practitioner on diagnosis and management. Valproate-associated hyperammonemic encephalopathy is a rare, underdiagnosed, serious and important entity to consider. We present a case of a patient with subarachnoid hemorrhage who received anticonvulsant prophylaxis with valproate and developed neuroworsening associated with high levels of ammoniemia and periodic discharge electroencephalographic patterns without other identifiable causes. Discontinuing valproic acid treatment and normalization of ammoniemia resulted in improvement in clinical and electroencephalographic neurological status.

Renal replacement therapy in neonates with hyperammonemia associated with inherited metabolic disease / 国际儿科学杂志

Neonatal hyperammonemia has great damage to the central nervous system, which can lead to severe disability and even death.Early reduction of blood ammonia and shortening the duration of hyperammonemia coma can improve the poor prognosis of the central nervous system.Renal replacement therapy can reduce blood ammonia quickly and effectively which is an important treatment for neonatal hyperammonemia.Common kidney replacement therapies include peritoneal dialysis, intermittent hemodialysis, continuous renal replacement therapy and hybrid therapy.This review aims to elaborate the indications of renal replacement therapy, the advantages and disadvantages of various renal replacement therapy modes in the treatment of neonatal hyperammonemia and hybrid therapy.

Aciduria argininosuccínica: informe de un caso de inicio neonatal / Argininosuccinic aciduria: Neonatal case report

Los defectos del ciclo de la urea son enfermedades metabólicas hereditarias que se producen por defecto en una de las enzimas encargadas de la desintoxicación del amonio, lo que genera su acumulación en el organismo. Las manifestaciones clínicas pueden presentarse en la etapa neonatal, con morbimortalidad elevada, o de forma tardía. La heterogeneidad de los síntomas y la falta de sospecha clínica en neonatos conducen a un diagnóstico erróneo y se puede confundir con sepsis neonatal o hemorragias cerebrales. El aumento de amonio plasmático en el examen bioquímico orienta su diagnóstico hacia un defecto del ciclo de la urea.La aciduria argininosuccínica es el tercer defecto más frecuente del ciclo de la urea y es causada por deficiencia de la enzima argininosuccínico liasa. Se presenta el informe de un caso de inicio neonatal. Los objetivos son enfatizar en su sospecha diagnóstica y proponer herramientas diagnósticas tempranas, como su incorporación a la pesquisa metabólica neonatal.

Urea cycle defects are inborn errors of metabolism produced by a defect in one of the enzymes responsible for the detoxification of ammonia, which generates its accumulation in the body. The clinical manifestations can present early, with high morbidity and mortality, or late onset. The heterogeneity of the symptoms and the lack of clinical suspicion in neonates leads to a wrong diagnosis, which can be confused with neonatal sepsis or cerebral hemorrhages. The increase in plasma ammonia in the biochemical examination orients his diagnosis towards a defect of the urea cycle.Argininosuccinic aciduria is the third most frequent defect of the urea cycle, and is caused by a argininosuccinate lyase deficiency. A neonatal onset case report is presented. The objective is to emphasize its diagnostic suspicion, and to propose early diagnostic tools such as its incorporation into the neonatal metabolic screening.

Analysis of the research status and intervention strategies for the treatment of hepatic encephalopathy based on gut microbiota regulation / 药学学报

Hepatic encephalopathy is a common metabolic neuropsychiatric syndrome in the development of end-stage liver disease. Since the concept of intestinal-liver-brain axis was proposed, the relationship between the pathogenesis of hepatic encephalopathy and the gut microbiota has been a hot research topic. In recent years, studies have confirmed that gut microbiota is involved in and affects various pathological processes of hepatic encephalopathy. This article combines the latest research progress at home and abroad to elaborate on the research status of regulating gut microbiota and thus interfering with the pathological process of hepatic encephalopathy, hoping to provide new ideas and methods for the intervention of hepatic encephalopathy based on the regulation of gut microbiota.

Un trastorno poco frecuente del ciclo de la urea en un recién nacido: deficiencia de N-acetilglutamato sintasa / A rare urea cycle disorder in a neonate: N-acetylglutamate synthetase deficiency

Los trastornos del ciclo de la urea (TCU) son enfermedades hereditarias con un posible desenlace desfavorable por hiperamoniemia grave. Se informa de una bebé con deficiencia de N-acetilglutamato sintasa (NAGS), quien tenía succión débil e hipotonicidad. Al examinarla, se observó hepatomegalia. El hemograma, los análisis y la gasometría eran normales, y las proteínas de la fase aguda, negativas. En los análisis, no se observaron cetonas en sangre, pero sí concentraciones elevadas de amoníaco. Las pruebas metabólicas no fueron concluyentes. Se inició el tratamiento de emergencia inmediatamente y recibió el alta el día 15 después del ingreso. Se confirmó deficiencia de NAGS mediante análisis de ADN. La paciente no tiene restricciones alimentarias ni toma medicamentos, excepto N-carbamil glutamato (NCG). La deficiencia de NAGS es el único TCU que puede tratarse específica y eficazmente con NCG. La detección temprana permite iniciar un tratamiento temprano y evitar los efectos devastadores de la hiperamoniemia

Urea cycle disorders (UCD), are genetically inherited diseases that may have a poor outcome due to to profound hyperammonemia. We report the case of a baby girl diagnosed as N-acetylglutamate synthase (NAGS) deficiency.The patient was evaluated due to diminished sucking and hypotonicity. Physical examination showed hepatomegaly. Complete blood count, biochemical values and blood gas analyses were normal, acute phase reactants were negative. Further laboratory analyses showed no ketones in blood and highly elevated ammonia. Metabolic tests were inconclusive. Emergency treatment was initiated immediately and she was discharged on the 15th day of admission. NAGS deficiency was confirmed by DNA-analysis. She is now without any dietary restriction or other medication, except N-carbamylglutamate (NCG).NAGS deficiency is the only UCD which can be specifically and effectively treated by NCG. Early recognition of disease will lead to early treatment that may prohibit devastating effects of hyperammonemia

Acidemia propiónica: diagnóstico clínico vs. cribado neonatal / Propionic acidemia: clinical diagnosis vs newborn screening

La acidemia propiónica es una rara enfermedad metabólica (prevalencia: 1/100 000), cuya detección puede hacerse de forma precoz mediante el cribado neonatal en las primeras 72 horas de vida. Puede tener una presentación neonatal grave, tardía intermitente o crónica progresiva. El tratamiento de las crisis consiste en la inversión del catabolismo que detiene la ingesta proteica con aporte intravenoso de calorías no proteicas. La mortalidad depende, fundamentalmente, de los episodios de descompensación aguda, mientras que la evolución asocia una alta tasa de secuelas neurológicas y déficits cognitivos.Se presenta el caso de una recién nacida de 11 días de vida con clínica de estancamiento ponderal, letargia, acidosis metabólica e hiperamonemia, que, debido a una falla en el proceso de cribado, no se benefició del diagnóstico precoz.A pesar de la ya existente detección por cribado, es vital mantener un alto índice de sospecha en casos sugestivos de metabolopatías.

Propionic acidemia is a rare metabolic disease (prevalence 1/100,000) that can be early detected with the newborn metabolic screening within the first 72 hours of life. It can have a severe neonatal presentation, a late intermittent onset or a chronic and progressive course. The treatment in the crisis consists in inverting the catabolism by pausing the protein intake and giving intravenous non-protein calories. Mortality depends mainly on acute episodes of decompensation, while evolution and prognosis associate a high rate of neurological sequelae and cognitive deficiencies.We present the case of an 11-day-old female newborn with failure to thrive, lethargy, metabolic acidosis and hyperammonemia that, because of a failed newborn screening process, could not be early diagnosed.In spite of the existence of early detection with the newborn metabolic screening, it is very important to keep a high suspicion in cases that suggest metabolic disorders.

Consensus on diagnosis and treatment of ornithine trans-carbamylase deficiency / 浙江大学学报·医学版

Ornithine transcarbamylase deficiency(OTCD)is a most common ornithine cycle (urea cycle) disorder. It is a X-link inherited disorder caused by

Hiperamonemia secundaria a infección urinaria en un paciente con malformación del tracto urinario en pediatría: a propósito de un caso / Hyperammonemia secondary to urinary tract infection in patients with pediatric urinary tract malformation: a case report

Ammonium is an important source of nitrogen for amino acid synthesis and is necessary for normal acid base balance. When ammonium concentrations are high it becomes a toxic compound. Hyperammonemia is a metabolic emergency. When underdiagnosed and not treated appropriately, it produces severe neurological sequelae and/or death. The clinical presentation of hyperammonemic encephalopathy varies, and includes from personality disorders, psychiatric disorders, confusion, irritability, lethargy, seizures to coma. Hyperammonemia occurs with an increase in ammonium production, as in intestinal hemorrhage, or with a decrease in the elimination of ammonium, such as in congenital metabolic errors, hepatic insufficiency or drug intoxication. As we can see, it may have multiple origins, but congenital errors of metabolism are always suspected as one of the causes. However, there are less frequent causes, such as urinary tract infection, especially in predisposing conditions. We describe the case of a 2-year-old boy with a history of horseshoe kidney and right ureterohydronephrosis, surgical correction of imperforate anus and rectal bladder fistula. This patient presented hyperammonemia with encephalopathy (Glasgow 7/15) while undergoing a urinary infection with Corynebacterium riegelii. Hyperammonemia is the result of the production in the dilated urinary tract of large amounts of ammonium due to bacterial urease and its subsequent reabsorption in the systemic circulation. The patient improved clinically (Glasgow 15/15) after parenteral antibiotic therapy and urinary tract clearance

El amonio es una fuente importante de nitrógeno para la síntesis de aminoácidos y necesario para el balance ácido base; si se encuentra elevado, se convierte en un compuesto tóxico. La hiperamoniemia es una urgencia metabólica; cuando no es diagnosticada y tratada de manera oportuna, produce graves secuelas de tipo neurológico o la muerte. La presentación clínica de la encefalopatía hiperamoniémica es variable, pudiéndose observar trastornos en la personalidad, trastornos psiquiátricos, confusión e irritabilidad, letargia, convulsión y coma. La hiperamoniemia se presenta por aumento en la producción de amonio, como en la hemorragia intestinal, o por disminución de la eliminación del mismo, como ocurre en los errores congénitos del metabolismo, en la insuficiencia hepática o en la intoxicación por fármacos. Puede tener múltiples orígenes, pero los errores congénitos del metabolismo son una de las causas que siempre se sospechan. Sin embargo, existen causas menos frecuentes, como la infección del tracto urinario (sobre todo en condiciones que predispongan a las mismas). Describimos aquí el caso de un niño de 2 años, con antecedentes de riñón en herradura y ureterohidronefrosis derecha, corrección quirúrgica de ano imperforado y fistula recto vesical. Este paciente presentó hiperamoniemia con encefalopatía (Glasgow 7/15) mientras cursaba una infección urinaria por Corynebacterium riegelii. La hiperamoniemia es el resultado de la producción en el tracto urinario dilatado de grandes cantidades de amonio, debido a la ureasa bacteriana y su posterior reabsorción en la circulación sistémica. El paciente mejoró clínicamente (Glasgow 15/15) después de la terapia antibiótica parenteral y desobstrucción de tracto urinario

The screening and genetic analysis of primary carnitine deficiency in the minority municipalities in Hainan Province / 中华检验医学杂志

Objective To investigate the incidence of neonatal carnitine deficiency (PCD) in eight minority autonomous cities and counties in Hainan Province (Changjiang, Ledong, Dongfang, Baoting, Baisha, Qiongzhong, Wuzhishan and Lingshui). Methods A total of 18, 701 cases of newborn filter paper dried blood samples were collected from August 1, 2017 to July 31, 2018 in eight minority autonomous cities and counties in Hainan Province, including 10051 male infants and 8650 female infants. Tandem mass spectrometry and the non-derivatized multi-amino acid, carnitine and succinylacetone assay kits produced by PE were used to detect free carnitine (C0) and acylcarnitine (C2, C3, C16, C18, etc.).The carnitine spec-trum was reexamined with the recall of mothers and infants whose C0 was less than 10μmol/L. Blood sam-ples from those who were still low were sent to the Beijing McKinnon gene for genetic diagnosis, and the urine samples were sent to the Guangzhou Golden Field for urine gas chromatography. Results Among the 18701 newborns, 5 cases were diagnosed with PCD. The incidence of neonatal PCD was 2.67/10000 (5/18701). Two cases of Li mutation c.388GA, two cases of Han mutation P.R254X and one case of Miao mutation P. Y84N were confirmed by gene detection. The confirmed children were treated with L-carnitine to avoid metabolic disorders or myocardial and skeletal muscle damage. Conclusions The incidence of neonatal PCD is high in eight cities and counties in Hainan Province. The mutation sites of neonatal PCD are different in Li and Han. The tandem mass spectrometry screening of PCD can guarantee the quality of the birth population.

Clinical research of two cases of late-onset ornithine carbamoyltransferase deficiency / 中华神经科杂志

Objective To explore the clinical characteristics of late-onset ornithine carbamoyltransferase deficiency (OTCD) in order to improve the clinicians' understanding of this disease.Methods The clinical,therapeutic and follow-up data of two patients with late-onset OTCD diagnosed in the Department of Neurology,Qilu Hospital of Shandong University from November 2017 to February 2018 were collected and analyzed.Results Case 1 is a 17-year-old male who was admitted into Qilu Hospital with recurrent dizziness and vomiting for 4 months,sudden mental abnormality and convulsion for 3 days.The liver dysfunction,respiratory alkalosis and hyperammonemia (434 μmol/L) had been found before his admission.His blood ammonia fluctuated obviously from 180 μ mol/L to 2998 μmol/L,though he was given hemodialysis and arginine infusion,and died on the fourth day after admission.Case 2 is a 15-year-old male,complained with recurrent dizziness,vomiting,bluntness and somnolence for 20 days.He was found with hyperammonemia (600 μmol/L) and liver dsyfunction in a local hospital.He was getting better after intravenous administration of arginine and liver protective drugs.After admission,the blood ammonia,liver function and amino acids,acylcarnitine profiling in dried blood spots,and organic acid analysis in urine were normal,and he has not recurred since restriction of protein diet.Brain magnetic resonane imaging of both patients showed cytotoxic edema of bilateral frontal lobe and insular cortex,and their genetic detection both showed c.119G＞A(p.R40H) hemizygous pathogenic mutation of OTC gene inherited from their respective mothers.Conclusion Unexplained hyperammonemia and acute encephalopathy with insular and frontal cortical involvement should be on the alert to the urea cycle disorders,especially OTCD.Early diagnosis and reasonable treatment are the key to changing the prognosis.

Genetic diagnosis of a Chinese pedigree affected with neonatal argininosuccinic aciduria / 中华医学遗传学杂志

Objective@#To explore the genetic basis of a neonate with argininosuccinic aciduria (ASA).@*Methods@#A neonate with lethargy and food refusal was admitted. The patient had myoclonus, myasthenia, uroschesis, irregular breathing and paroxysmal ventricular tachycardia, and died at 75 hours after birth. Laboratory test showed marked increase in blood ammonia (1249.8 μmol/L). Peripheral blood samples of the patient, her parents and sister were collected and subjected to trio whole-exome sequencing.@*Results@#Whole-exome sequencing revealed that the patient has carried compound heterozygous mutations of the argininosuccinate lyase (ASL) gene, namely c. 425(exon5)_c.426(exon5) insAGCTCCCAGCT (p.Thr142Thrfs*37) and c. 626(exon8)delT (p.Leu209Argfs*42). The patient was diagnosed as ASA caused by ASL gene mutations. Her parents and her elder sister were heterozygous carriers of the above mutations and had a normal phenotype.@*Conclusion@#ASA is a severe congenital genetic metabolic disease and can manifest as onset of hyperammonemia in neonates. The clinical diagnosis is difficult and ASL gene testing may be helpful.

Successful management of hyperammonemia syndrome in a patient after skin transplantation: a case report and a literature review on 41 patients / 中华危重病急救医学

Hyperammonemia syndrome (HS) is a comparatively rare but often fatal clinical syndrome characterized by progressive respiratory alkalosis and abrupt mental status alteration associated with markedly elevated plasma ammonium levels. Although the exact mechanism of HS remains unclear, infection with urease producing microbes is proposed as the main etiology of HS recently. A patient with HS after repeated autologous skin transplantation was admitted to Tianjin First Center Hospital in March 2018, presented with fever, coma and epilepsy. The infection of Mycoplasma hominis was confirmed in blood sample by high throughput gene detection. The patient was survived after multimodal management including antimicrobial treatment, aggressive ammonia removal by continuous renal replacement therapy in combination with lactulose, and mechanical ventilation. She was successfully discharged from intensive care unit (ICU) with clear consciousness, normal temperature and smooth breath. In view of the experience of the case treatment, a review of literature was conducted to discuss the epidemiology and clinical characteristics, possible etiologies and mechanisms, and outcomes with emphasis on treatment strategies of HS and to promote more clinicians to recognize this rare disease.