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Maghmoul Y, Wiedemann A, Barcat L, Parente F, Allard P, Alvarez F, Jouvet P. Hyperosmolarity in children with hyperammonemia: a risk of brain herniation at the start of renal replacement therapy. Front Pediatr 2024; 12:1431008. [PMID: 39040669 PMCID: PMC11260712 DOI: 10.3389/fped.2024.1431008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 06/24/2024] [Indexed: 07/24/2024] Open
Abstract
Purpose Renal replacement therapy (RRT) is used in hyperammonemia to reduce the concentration of ammonia in the blood. In the case of plasma hyperosmolarity, RRT can also rapidly decrease plasma osmolarity, which may increase cerebral edema in these patients and favor the occurrence of brain herniation. Methods We conducted a retrospective clinical study in a tertiary care university-affiliated hospital. All patients admitted in a Pediatric Intensive Care Unit (PICU), less than 18 years old with ammonemia >150 µmol/L and who underwent RRT between January 2015 and June 2023 were included. We collected data on plasma osmolarity levels, osmolar gap and blood ammonia levels before and during RRT. Results Eleven patients were included (10 with acute liver failure and 1 with a urea cycle disorders). Their mean age was 36.2 months. Before RRT, the median highest measured osmolarity was 320 (305-324) mOsm/L, whereas the median calculated osmolarity was 303 (293-314) mOsm/L, corresponding to an osmolar gap of 14 mOsm/L. Ammonia blood level over 400 µmol/L are significantly associated with higher plasma osmolarity (P-Value <0.001). In one case, a patient had a brain herniation episode after a quick osmolar drop. This episode was reversed by the administration of hyperosmolar agents and the temporary suspension of RRT. Conclusion This study highlights the hyperosmolarity and high osmolar gap that occur in children with hyperammonemia. A careful monitoring and control of plasma osmolarity evolution may alert clinician on the risk of occurrence of neurological complication such as brain herniation.
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Affiliation(s)
- Yousra Maghmoul
- Pediatric Intensive Care Unit, Department of Pediatrics CHU Sainte-Justine, Université de Montréal, Montreal, QC, Canada
| | - Arnaud Wiedemann
- Pediatric Intensive Care Unit, Department of Pediatrics CHU Sainte-Justine, Université de Montréal, Montreal, QC, Canada
- Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Nancy, France
| | - Lucile Barcat
- Pediatric Intensive Care Unit, Department of Pediatrics CHU Sainte-Justine, Université de Montréal, Montreal, QC, Canada
| | - Fabienne Parente
- Biochemical and Molecular Medicine Department CHU Sainte-Justine, Université de Montréal, Montreal, QC, Canada
| | - Pierre Allard
- Department of Pediatrics CHU Sainte-Justine, Université de Montréal, Montreal, QC, Canada
| | - Fernando Alvarez
- Hepato-gastro-enterology and Nutrition Unit, Department of Pediatrics CHU Sainte-Justine, Université de Montréal, Montreal, QC, Canada
| | - Philippe Jouvet
- Pediatric Intensive Care Unit, Department of Pediatrics CHU Sainte-Justine, Université de Montréal, Montreal, QC, Canada
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2
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Bremova-Ertl T, Hofmann J, Stucki J, Vossenkaul A, Gautschi M. Inborn Errors of Metabolism with Ataxia: Current and Future Treatment Options. Cells 2023; 12:2314. [PMID: 37759536 PMCID: PMC10527548 DOI: 10.3390/cells12182314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/09/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
A number of hereditary ataxias are caused by inborn errors of metabolism (IEM), most of which are highly heterogeneous in their clinical presentation. Prompt diagnosis is important because disease-specific therapies may be available. In this review, we offer a comprehensive overview of metabolic ataxias summarized by disease, highlighting novel clinical trials and emerging therapies with a particular emphasis on first-in-human gene therapies. We present disease-specific treatments if they exist and review the current evidence for symptomatic treatments of these highly heterogeneous diseases (where cerebellar ataxia is part of their phenotype) that aim to improve the disease burden and enhance quality of life. In general, a multimodal and holistic approach to the treatment of cerebellar ataxia, irrespective of etiology, is necessary to offer the best medical care. Physical therapy and speech and occupational therapy are obligatory. Genetic counseling is essential for making informed decisions about family planning.
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Affiliation(s)
- Tatiana Bremova-Ertl
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, 3010 Bern, Switzerland; (J.H.); (J.S.)
- Center for Rare Diseases, University Hospital Bern (Inselspital) and University of Bern, 3010 Bern, Switzerland
| | - Jan Hofmann
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, 3010 Bern, Switzerland; (J.H.); (J.S.)
| | - Janine Stucki
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, 3010 Bern, Switzerland; (J.H.); (J.S.)
| | - Anja Vossenkaul
- Division of Pediatric Endocrinology, Diabetes and Metabolism, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland; (A.V.); (M.G.)
| | - Matthias Gautschi
- Division of Pediatric Endocrinology, Diabetes and Metabolism, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland; (A.V.); (M.G.)
- Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
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3
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Ibrahim MS, Gold JI, Woodall A, Yilmaz BS, Gissen P, Stepien KM. Diagnostic and Management Issues in Patients with Late-Onset Ornithine Transcarbamylase Deficiency. CHILDREN (BASEL, SWITZERLAND) 2023; 10:1368. [PMID: 37628367 PMCID: PMC10453542 DOI: 10.3390/children10081368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 07/24/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023]
Abstract
Ornithine transcarbamylase deficiency (OTCD) is the most common inherited disorder of the urea cycle and, in general, is transmitted as an X-linked recessive trait. Defects in the OTC gene cause an impairment in ureagenesis, resulting in hyperammonemia, which is a direct cause of brain damage and death. Patients with late-onset OTCD can develop symptoms from infancy to later childhood, adolescence or adulthood. Clinical manifestations of adults with OTCD vary in acuity. Clinical symptoms can be aggravated by metabolic stressors or the presence of a catabolic state, or due to increased demands upon the urea. A prompt diagnosis and relevant biochemical and genetic investigations allow the rapid introduction of the right treatment and prevent long-term complications and mortality. This narrative review outlines challenges in diagnosing and managing patients with late-onset OTCD.
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Affiliation(s)
- Majitha Seyed Ibrahim
- Department of Chemical Pathology, Teaching Hospital Batticaloa, Batticaloa 30000, Sri Lanka
| | - Jessica I. Gold
- Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alison Woodall
- Adult Inherited Metabolic Diseases, Salford Royal Hospital, Northern Care Alliance NHS Foundation Trust, Salford M6 8HD, UK
| | - Berna Seker Yilmaz
- Great Ormond Street Institute of Child Health, University College London, London WC1E 6BT, UK
| | - Paul Gissen
- Great Ormond Street Institute of Child Health, University College London, London WC1E 6BT, UK
- Department of Paediatric Metabolic Medicine, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
- National Institute of Health Research, Great Ormond Street Biomedical Research Centre, London WC1N 1EH, UK
| | - Karolina M. Stepien
- Adult Inherited Metabolic Diseases, Salford Royal Hospital, Northern Care Alliance NHS Foundation Trust, Salford M6 8HD, UK
- Division of Cardiovascular Sciences, University of Manchester, Manchester M13 9PL, UK
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4
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Deutsch-Link S, Moon AM. The Ongoing Debate of Serum Ammonia Levels in Cirrhosis: the Good, the Bad, and the Ugly. Am J Gastroenterol 2023; 118:10-13. [PMID: 36001400 PMCID: PMC9822843 DOI: 10.14309/ajg.0000000000001966] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/12/2022] [Indexed: 02/04/2023]
Abstract
Serum ammonia testing in hepatic encephalopathy (HE) has been long debated in the field of hepatology. Although central to the pathophysiology of HE, serum ammonia testing is fraught with complexities that can lead to challenges in laboratory collection and interpretation. Although there is some disagreement across guideline organizations regarding routine testing of ammonia in HE, all acknowledge that normal values, although possible in HE, may warrant reconsideration of the diagnosis. In this study, we propose a nuanced approach to ammonia testing in HE. Serum ammonia testing provides little additional benefit in clinical scenarios with a high or low pretest probability for HE. However, if the pretest probability for HE is uncertain, a low ammonia level may reduce the posttest probability of HE. In this scenario, other etiologies of altered mental status should be explored. Future research should focus on developing a standardized approach to serum ammonia collection, processing, and interpretation.
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Affiliation(s)
- Sasha Deutsch-Link
- Division of Gastroenterology and Hepatology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
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5
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Long Noncoding RNAs Regulate Hyperammonemia-Induced Neuronal Damage in Hepatic Encephalopathy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:7628522. [PMID: 35464767 PMCID: PMC9021992 DOI: 10.1155/2022/7628522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/18/2022] [Accepted: 02/01/2022] [Indexed: 12/13/2022]
Abstract
Background. Hyperammonemia can result in various neuropathologies, including sleep disturbance, memory loss, and motor dysfunction in hepatic encephalopathy. Long noncoding RNA (lncRNA) as a group of noncoding RNA longer than 200 nucleotides is emerging as a promising therapeutic target to treat diverse diseases. Although lncRNAs have been linked to the pathogenesis of various diseases, their function in hepatic encephalopathy has not yet been elucidated. Research Design and Methods. To identify the roles of lncRNAs in hepatic encephalopathy brain, we used a bile duct ligation (BDL) mouse model and examined the alteration of neuronal cell death markers and neuronal structure-related proteins in BDL mouse cortex tissue. Furthermore, analysis of the transcriptome of BDL mouse brain cortex tissues revealed several lncRNAs critical to the apoptosis and neuronal structural changes associated with hepatic encephalopathy. Results. We confirmed the roles of the lncRNAs, ZFAS1, and GAS5 as strong candidate lncRNAs to regulate neuropathologies in hepatic encephalopathy. Our data revealed the roles of lncRNAs, ZFAS1, and GAS5, on neuronal cell death and neural structure in hyperammonemia in in vivo and in vitro conditions. Conclusion. Thus, we suggest that the modulation of these lncRNAs may be beneficial for the treatment of hepatic encephalopathy.
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Serum Ammonia in Cirrhosis: Clinical Impact of Hyperammonemia, Utility of Testing, and National Testing Trends. Clin Ther 2022; 44:e45-e57. [DOI: 10.1016/j.clinthera.2022.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/10/2022] [Accepted: 01/10/2022] [Indexed: 02/07/2023]
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López-Cervantes M, Quintanar-Stephano A, Alcauter-Solórzano S, Hernández-Pando R, Aguilar-Roblero R, Gasca-Martínez D, Ortíz JJ, Vázquez-Martínez O, Ximénez-Camilli C, Díaz-Muñoz M. Cerebellar spongiform degeneration is accompanied by metabolic, cellular, and motor disruption in male rats with portacaval anastomosis. J Neurosci Res 2021; 99:2287-2304. [PMID: 34061383 DOI: 10.1002/jnr.24853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 04/14/2021] [Accepted: 04/22/2021] [Indexed: 12/12/2022]
Abstract
The episodes of cerebral dysfunction, known as encephalopathy, are usually coincident with liver failure. The primary metabolic marker of liver diseases is the increase in blood ammonium, which promotes neuronal damage. In the present project, we used an experimental model of hepatic encephalopathy in male rats by portacaval anastomosis (PCA) surgery. Sham rats had a false operation. After 13 weeks of surgery, the most distinctive finding was vacuolar/spongiform neurodegeneration exclusively in the molecular layer of the cerebellum. This cerebellar damage was further characterized by metabolic, histopathological, and behavioral approaches. The results were as follows: (a) Cellular alterations, namely loss of Purkinje cells, morphological changes, such as swelling of astrocytes and Bergmann glia, and activation of microglia; (b) Cytotoxic edema, shown by an increase in aquaporin-4 and N-acetylaspartate and a reduction in taurine and choline-derivate osmolytes; (c) Metabolic adjustments, noted by the elevation of circulating ammonium, enhanced presence of glutamine synthetase, and increase in glutamine and creatine/phosphocreatine; (d) Inflammasome activation, detected by the elevation of the marker NLRP3 and microglial activation; (e) Locomotor deficits in PCA rats as assessed by the Rotarod and open field tests. These results lead us to suggest that metabolic disturbances associated with PCA can generate the cerebellar damage that is similar to morphophysiological modifications observed in amyloidogenic disorders. In conclusion, we have characterized a distinctive cerebellar multi-disruption accompanied by high levels of ammonium and associated with spongiform neurodegeneration in a model of hepatic hypofunctioning.
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Affiliation(s)
- Mayra López-Cervantes
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro, Mexico
| | - Andrés Quintanar-Stephano
- Departmento de Fisiología y Farmacología, Centro de Ciencia Básica, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Sarael Alcauter-Solórzano
- Laboratorio Nacional de Imagenología por Resonancia Magnética, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro, Mexico
| | - Rogelio Hernández-Pando
- Seccion de Patología Experimental, Departamento de Patología, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Ciudad de México, Mexico
| | - Raúl Aguilar-Roblero
- División de Neurociencias, Instituto de Fisiología Celular, UNAM, Ciudad de México, Mexico
| | - Deisy Gasca-Martínez
- Unidad de Análisis Conductual, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro, Mexico
| | - Juan J Ortíz
- Laboratorio Nacional de Imagenología por Resonancia Magnética, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro, Mexico
| | - Olivia Vázquez-Martínez
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro, Mexico
| | - Cecilia Ximénez-Camilli
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro, Mexico
| | - Mauricio Díaz-Muñoz
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro, Mexico
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8
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Sen K, Anderson AA, Whitehead MT, Gropman AL. Review of Multi-Modal Imaging in Urea Cycle Disorders: The Old, the New, the Borrowed, and the Blue. Front Neurol 2021; 12:632307. [PMID: 33995244 PMCID: PMC8113618 DOI: 10.3389/fneur.2021.632307] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/26/2021] [Indexed: 12/16/2022] Open
Abstract
The urea cycle disorders (UCD) are rare genetic disorder due to a deficiency of one of six enzymes or two transport proteins that act to remove waste nitrogen in form of ammonia from the body. In this review, we focus on neuroimaging studies in OTCD and Arginase deficiency, two of the UCD we have extensively studied. Ornithine transcarbamylase deficiency (OTCD) is the most common of these, and X-linked. Hyperammonemia (HA) in OTCD is due to deficient protein handling. Cognitive impairments and neurobehavioral disorders have emerged as the major sequelae in Arginase deficiency and OTCD, especially in relation to executive function and working memory, impacting pre-frontal cortex (PFC). Clinical management focuses on neuroprotection from HA, as well as neurotoxicity from other known and yet unclassified metabolites. Prevention and mitigation of neurological injury is a major challenge and research focus. Given the impact of HA on neurocognitive function of UCD, neuroimaging modalities, especially multi-modality imaging platforms, can bring a wealth of information to understand the neurocognitive function and biomarkers. Such information can further improve clinical decision making, and result in better therapeutic interventions. In vivo investigations of the affected brain using multimodal neuroimaging combined with clinical and behavioral phenotyping hold promise. MR Spectroscopy has already proven as a tool to study biochemical aberrations such as elevated glutamine surrounding HA as well as to diagnose partial UCD. Functional Near Infrared Spectroscopy (fNIRS), which assesses local changes in cerebral hemodynamic levels of cortical regions, is emerging as a non-invasive technique and will serve as a surrogate to fMRI with better portability. Here we review two decades of our research using non-invasive imaging and how it has contributed to an understanding of the cognitive effects of this group of genetic conditions.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Neurodevelopmental Pediatrics, Department of Neurology, Children's National Hospital, George Washington University School of Medicine, Washington, DC, United States
| | - Afrouz A Anderson
- Department of Research, Focus Foundation, Crofton, MD, United States
| | - Matthew T Whitehead
- Department of Radiology, Children's National Hospital, George Washington University School of Medicine, Washington, DC, United States
| | - Andrea L Gropman
- Division of Neurogenetics and Neurodevelopmental Pediatrics, Department of Neurology, Children's National Hospital, George Washington University School of Medicine, Washington, DC, United States
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9
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McGowan M, Ferreira C, Whitehead M, Basu SK, Chang T, Gropman A. The Application of Neurodiagnostic Studies to Inform the Acute Management of a Newborn Presenting With Sarbamoyl Shosphate Synthetase 1 Deficiency. Child Neurol Open 2021; 8:2329048X20985179. [PMID: 33644249 PMCID: PMC7841664 DOI: 10.1177/2329048x20985179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 11/14/2020] [Accepted: 12/06/2020] [Indexed: 11/17/2022] Open
Abstract
Neonatal-onset urea cycle disorders (UCDs) may result in hyperammonemic (HA) encephalopathy presenting with several neurologic sequelae including seizures, coma, and death. However, no recommendations are given in how and when neurodiagnostic studies should be used to screen or assess for these neurologic complications. We present a case of carbamoyl phosphate synthetase 1 (CPS1) deficiency in a newborn female in which electroencephalogram monitoring to assess encephalopathy and seizures, and magnetic resonance imaging measurements of brain metabolites were used to guide care during her hyperammonemic crisis. Her neurologic course and response to treatment characterizes the significant neurologic impact of HA encephalopathy. Our group herein proposes a clinical neurodiagnostic pathway for managing acute HA encephalopathy.
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Affiliation(s)
- Meaghan McGowan
- University of Illinois College of Medicine, Chicago, IL,
USA
| | - Carlos Ferreira
- Medical Genomics and Metabolic Genetics Branch, National
Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Matthew Whitehead
- Neuroradiology, Children’s National Hospital, George
Washington University School of Medicine, Washington, DC, USA
| | - Sudeepta K. Basu
- Neonatology, Children’s National Hospital, George Washington
University School of Medicine, Washington, DC, USA
| | - Taeun Chang
- Neurology, Children’s National Hospital, George Washington
University School of Medicine, Washington, DC, USA
| | - Andrea Gropman
- Neurology, Children’s National Hospital, George Washington
University School of Medicine, Washington, DC, USA
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10
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Li J, Li R, Gao Y, Jin X, Zhang J, Ren J, Hou Y, Wang X, Wang G. Increasing serum ammonia level is a risk factor for the prognosis of critically ill patients: A multicenter retrospective cohort study. J Crit Care 2020; 62:218-222. [PMID: 33429115 DOI: 10.1016/j.jcrc.2020.12.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/15/2020] [Accepted: 12/27/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE To assess the association between serum ammonia level upon admission during the initial intensive care unit (ICU) stay and mortality. MATERIALS AND METHODS This retrospective cohort study included 2703 adult patients in eICU Collaborative Research Database. The ICU mortality within ammonia deciles were assessed. Logistic regression analyses were performed to analyze the relationship between ammonia and mortality. RESULTS We defined three ammonia categories: <47, 47-111, and ≥111 μg/dL, corresponding to low, intermediate, and high ICU mortality. Increased ammonia was significantly associated with increased ICU mortality (per 10 μg/dL increase: odds ratio, 1.070 [95% confidence intervals, 1.05-1.09]; intermediate vs. low: 1.90 [1.41-2.56]; high vs. low: 4.38 [2.99-6.41]) and in-hospital mortality (1.06 [1.04-1.08]; 1.45 [1.13-1.87]; 3.41 [2.43-4.79]). Adding ammonia to the Acute Physiology and Chronic Health Evaluation (APACHE) IV score improved the area under the curve from 0.826 to 0.839 (P < 0.001) and from 0.806 to 0.813 (P = 0.001) for ICU and in-hospital mortality, respectively. Interaction and subgroup analyses demonstrated consistent results in patients with different APACHE IV scores, with or without hepatic diseases. CONCLUSIONS Elevated serum ammonia level in critically ill patients upon admission was an early risk factor for higher ICU and in-hospital mortality.
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Affiliation(s)
- Jiamei Li
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Ruohan Li
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Ya Gao
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xuting Jin
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jingjing Zhang
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jiajia Ren
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Yanli Hou
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xiaochuang Wang
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Gang Wang
- Department of Critical Care Medicine, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
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11
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Zhang Q, You J, Zhu W, Wu Z, Xiong J. Rapid Quantification of Urinary Organic Acids by HPLC Mass Spectrometry to Assess Nutritional Individuality in Chinese Children. ANAL SCI 2020; 36:1191-1196. [PMID: 32389902 DOI: 10.2116/analsci.20p038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A urinary organic acids profile can be utilized as an effective screening tool for analyzing abnormality of nutrient metabolism. By using these metabolic markers in conjunction with one another, it helps in understanding how individual nutrient metabolism is executed and to determine where there may be imbalances in the metabolic cycle. In this study, we developed a rapid quantification method of 20 urinary organic acids by HPLC-mass spectrometry. A pre-analytical process of organic acid extraction from a urine sample is crucial in this methodology. The process was accomplished by liquid-liquid extraction followed by strong anion exchange. Compared with previous methods, this method greatly reduces the analysis time and allows for the simultaneous quantification of 20 organic acids within 10 min for the first time. This methodology enabled us to analyze urine samples collected from 34 Chinese children. The abnormalities of some urinary organic acids were found in this group, which revealed evidence of functional inadequacy of specific nutrients. The preliminary data in this study confirmed the suitability of the method for rapid and accurate quantification of the target organic acids in urine samples.
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Affiliation(s)
- Qichen Zhang
- Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China
| | - Jia You
- West China School of Public Health and Healthy Food Evaluation Research Center, Sichuan University
| | - Wenli Zhu
- Chengdu MediMass Technology CO., LTD
| | | | - Jingyuan Xiong
- West China School of Public Health and Healthy Food Evaluation Research Center, Sichuan University
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12
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Reinert JP, Burnham K. Non-Lactulose Medication Therapies for the Management of Hepatic Encephalopathy: A Literature Review. J Pharm Pract 2020; 34:922-933. [PMID: 32878558 DOI: 10.1177/0897190020953024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The most appropriate medication regimen to mitigate the consequences hepatic encephalopathy remains inconclusive. This review seeks to serve as a reference for clinicians to help guide therapy decisions with regard to hepatic encephalopathy. METHODS A comprehensive literature review between August 2018 and April 2019 was accomplished with the assistance of a medical librarian. Sources of literature review include PubMed, MEDLINE, SCOPUS, ProQuest Central, CINAHL, and ProQuest Dissertations. The authors selected randomized clinical and double-blind cross-over trials evaluating probiotics, zinc, polyethylene glycol, rifaximin, and flumazenil. Sixteen clinical trials are discussed in this review. Pertinent safety, efficacy, and statistical and clinical outcomes are summarized by the authors. CONCLUSIONS The most appropriate regimen to mitigate the consequences of hepatic encephalopathy remains elusive; however, the agents discussed within this review offer alternative options for patients unresponsive to or intolerant of traditional lactulose therapy. This review seeks to serve as a repository for relevant clinical trials, and as a reference for clinicians to help guide therapy decisions.
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Affiliation(s)
- Justin P Reinert
- Ben and Maytee Fisch College of Pharmacy, 12347The University of Texas at Tyler, TX, USA
| | - Kevin Burnham
- Ben and Maytee Fisch College of Pharmacy, 12347The University of Texas at Tyler, TX, USA
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13
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Anderson AA, Gropman A, Le Mons C, Stratakis CA, Gandjbakhche AH. Hemodynamics of Prefrontal Cortex in Ornithine Transcarbamylase Deficiency: A Twin Case Study. Front Neurol 2020; 11:809. [PMID: 32922350 PMCID: PMC7456944 DOI: 10.3389/fneur.2020.00809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 06/29/2020] [Indexed: 11/30/2022] Open
Abstract
Ornithine transcarbamylase deficiency (OTCD) is the most common form of urea cycle disorder characterized by the presence of hyperammonemia (HA). In patients with OTCD, HA is known to cause impairments in domains of executive function and working memory. Monitoring OTCD progression and investigating neurocognitive biomarkers can, therefore, become critical in understanding the underlying brain function in a population with OTCD. We used functional near infrared spectroscopy (fNIRS) to examine the hemodynamics of prefrontal cortex (PFC) in a fraternal twin with and without OTCD. fNIRS is a non-invasive and wearable optical technology that can be used to assess cortical hemodynamics in a realistic clinical setting. We quantified the hemodynamic variations in total-hemoglobin as assessed by fNIRS while subjects performed the N-back working memory (WM) task. Our preliminary results showed that the sibling with OTCD had higher variation in a very low frequency band (<0.03 Hz, related to mechanism of cerebral autoregulation) compared to the control sibling. The difference between these variations was not as prominent in the higher frequency band, indicating the possible role of impaired autoregulation and cognitive function due to presence of HA. We further examined the functional connectivity in PFC, where the OTCD sibling showed lower interhemispheric functional connectivity as the task load increased. Our pilot results are the first to show the utility of fNIRS in monitoring OTCD cortical hemodynamics, indicating the possibility of inefficient neurocognitive function. This study provides a novel insight into the monitoring of OTCD focusing on the contribution of physiological process and neurocognitive function in this population.
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Affiliation(s)
- Afrouz A. Anderson
- National Institutes of Health (NIH), National Institute of Child Health and Human Development, Bethesda, MD, United States
| | - Andrea Gropman
- Children's National Medical Center, Division of Neurogenetics and Neurodevelopmental Pediatrics, Washington, DC, United States
| | - Cynthia Le Mons
- National Urea Cycle Disorders Foundation, Pasadena, CA, United States
| | - Constantine A. Stratakis
- National Institutes of Health (NIH), National Institute of Child Health and Human Development, Bethesda, MD, United States
| | - Amir H. Gandjbakhche
- National Institutes of Health (NIH), National Institute of Child Health and Human Development, Bethesda, MD, United States
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Toroghi MK, Cluett WR, Mahadevan R. A Personalized Multiscale Modeling Framework for Dose Selection in Precision Medicine. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c01070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masood Khaksar Toroghi
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3E5
| | - William R. Cluett
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3E5
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3E5
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada, M5S 3E5
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15
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Gerstein MT, Markus AR, Gianattasio KZ, Le Mons C, Bartos J, Stevens DM, Mew NA. Choosing between medical management and liver transplant in urea cycle disorders: A conceptual framework for parental treatment decision-making in rare disease. J Inherit Metab Dis 2020; 43:438-458. [PMID: 31883128 PMCID: PMC7318329 DOI: 10.1002/jimd.12209] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/27/2019] [Accepted: 12/20/2019] [Indexed: 02/06/2023]
Abstract
Urea cycle disorders (UCD) are rare inherited metabolic disorders caused by deficiencies of enzymes and transporters required to convert neurotoxic ammonia into urea. These deficiencies cause elevated blood ammonia, which if untreated may result in death, but even with optimal medical management, often results in recurrent brain damage. There are two major treatments for UCD: medical management or liver transplantation. Both are associated with mortality and morbidity but the evidence comparing outcomes is sparse. Thus, families face a dilemma: should their child be managed medically, or should they undergo a liver transplant? To (a) describe the factors that contribute to treatment choice among parents of children diagnosed with UCD and to (b) organise these factors into a conceptual framework that reflects how these issues interrelate to shape the decision-making experience of this population. Utilising grounded theory, qualitative data were collected through semi-structured interviews with parents (N = 35) and providers (N = 26) of children diagnosed with UCD and parent focus groups (N = 19). Thematic content analysis and selective and axial coding were applied. The framework highlights the life-cycle catalysts that frame families' personal perceptions of risks and benefits and describes the clinical, personal, social, and system factors that drive treatment choice including disease severity, stability, and burden, independence, peer experiences, and cost, coverage and access to quality care. Findings equip providers with evidence upon which to prepare for productive patient interactions about treatment options. They also provide a foundation for the development of patient-centred outcome measures to better evaluate effectiveness of treatments in this population.
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Affiliation(s)
- Maya T. Gerstein
- Department of Health Policy and Management, Milken Institute School of Public HealthThe George Washington UniversityWashingtonDistrict of Columbia
| | - Anne R. Markus
- Department of Health Policy and Management, Milken Institute School of Public HealthThe George Washington UniversityWashingtonDistrict of Columbia
| | - Kan Z. Gianattasio
- Department of Health Policy and Management, Milken Institute School of Public HealthThe George Washington UniversityWashingtonDistrict of Columbia
| | | | - Janice Bartos
- National Urea Cycle Disorders FoundationPasadenaCalifornia
| | - David M. Stevens
- Department of Health Policy and Management, Milken Institute School of Public HealthThe George Washington UniversityWashingtonDistrict of Columbia
| | - Nicholas Ah Mew
- Rare Disease Institute, Children's National Health SystemWashingtonDistrict of Columbia
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16
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Gropman AL, Anderson A. Novel imaging technologies for genetic diagnoses in the inborn errors of metabolism. JOURNAL OF TRANSLATIONAL GENETICS AND GENOMICS 2020; 4:429-445. [PMID: 35529470 PMCID: PMC9075742 DOI: 10.20517/jtgg.2020.09] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Many inborn errors of metabolism and genetic disorders affect the brain. The brain biochemistry may differ from that in the periphery and is not accessible by simple blood and urine sampling. Therefore, neuroimaging has proven to be a valuable tool to not only evaluate the brain structure, but also biochemistry, blood flow and function. Neuroimaging in patients with inborn errors of metabolism can include additional sequences in addition to T1 and T2-weighted imaging because in early stages, there may be no significant findings on the routine sequnces due to the lack of sensitivity or the evolution of abnormalities lags behind the ability of the imaging to detect it. In addition, findings on T1 and T2-weighted imaging of several inborn errors of metabolism may be non-specific and be seen in other non-genetic conditions. Therefore, additional neuroimaging modalities that have been employed including diffusion tensor imaging (DTI), magnetic resonance spectroscopy, functional MRI (fMRI), functional near infrared spectroscopy (fNIRS), or positron emission tomography (PET) imaging may further inform underlying changes in myelination, biochemistry, and functional connectivity. The use of Magnetic Resonance Spectroscopy in certain disorders may add a level of specificity depending upon the metabolite levels that are abnormal, as well as provide information about the process of brain injury (i.e., white matter, gray matter, energy deficiency, toxic buildup or depletion of key metabolites). It is even more challenging to understand how genetic or metabolic disorders contribute to short and/or long term changes in cognition which represent the downstream effects of IEMs. In order to image “cognition” or the downstream effects of a metabolic disorder on domains of brain function, more advanced techniques are required to analyze underlying fiber tracts or alternatively, methods such as fMRI enable generation of brain activation maps after both task based and resting state conditions. DTI can be used to look at changes in white matter tracks. Each imaging modality can explore an important aspect of the anatomy, physiology or biochemisty of the central nervous system. Their properties, pros and cons are discussed in this article. These imaging modalities will be discussed in the context of several inborn errors of metabolism including Galactosemia, Phenylketonruia, Maple syrup urine disease, Methylmalonic acidemia, Niemann-Pick Disease, type C1, Krabbe Disease, Ornithine transcarbamylase deficiency, Sjogren Larsson syndrome, Pelizeaus-Merzbacher disease, Pyruvate dehydrogenase deficiency, Nonketotic Hyperglycinemia and Fabry disease. Space constraints do not allow mention of all the disorders in which one of these modalities has been investigated, or where it would add value to diagnosis or disease progression.
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Affiliation(s)
- Andrea L Gropman
- Department of Neurology, Children's National Medical Center, Washington, DC 20010, USA
| | - Afrouz Anderson
- Department of Research, Focus Foundation, Crofton, MD 21035, USA
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17
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Urea cycle disorders-update. J Hum Genet 2019; 64:833-847. [PMID: 31110235 DOI: 10.1038/s10038-019-0614-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 04/14/2019] [Accepted: 04/15/2019] [Indexed: 12/14/2022]
Abstract
The urea cycle is a metabolic pathway for the disposal of excess nitrogen, which arises primarily as ammonia. Nitrogen is essential for growth and life-maintenance, but excessive ammonia leads to life-threatening conditions. The urea cycle disorders (UCDs) comprise diseases presenting with hyperammonemia that arise in either the neonatal period (about 50% of cases) or later. Congenital defects of the enzymes or transporters of the urea cycle cause the disease. This cycle utilizes five enzymes, two of which, carbamoylphosphate synthetase 1 and ornithine transcarbamylase are present in the mitochondrial matrix, whereas the others (argininosuccinate synthetase, argininosuccinate lyase and arginase 1) are present in the cytoplasm. In addition, N-acetylglutamate synthase and at least two transporter proteins are essential to urea cycle function. Severity and age of onset depend on residual enzyme or transporter function and are related to the respective gene mutations. The strategy for therapy is to prevent the irreversible toxicity of high-ammonia exposure to the brain. The pathogenesis and natural course are poorly understood because of the rarity of the disease, so an international registry system and novel clinical trials are much needed. We review here the current concepts of the pathogenesis, diagnostics, including genetics and treatment of UCDs.
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18
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Cudalbu C, Taylor-Robinson SD. Brain Edema in Chronic Hepatic Encephalopathy. J Clin Exp Hepatol 2019; 9:362-382. [PMID: 31360029 PMCID: PMC6637228 DOI: 10.1016/j.jceh.2019.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/15/2019] [Accepted: 02/06/2019] [Indexed: 02/07/2023] Open
Abstract
Brain edema is a common feature associated with hepatic encephalopathy (HE). In patients with acute HE, brain edema has been shown to play a crucial role in the associated neurological deterioration. In chronic HE, advanced magnetic resonance imaging (MRI) techniques have demonstrated that low-grade brain edema appears also to be an important pathological feature. This review explores the different methods used to measure brain edema ex vivo and in vivo in animal models and in humans with chronic HE. In addition, an in-depth description of the main studies performed to date is provided. The role of brain edema in the neurological alterations linked to HE and whether HE and brain edema are the manifestations of the same pathophysiological mechanism or two different cerebral manifestations of brain dysfunction in liver disease are still under debate. In vivo MRI/magnetic resonance spectroscopy studies have allowed insight into the development of brain edema in chronic HE. However, additional in vivo longitudinal and multiparametric/multimodal studies are required (in humans and animal models) to elucidate the relationship between liver function, brain metabolic changes, cellular changes, cell swelling, and neurological manifestations in chronic HE.
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Key Words
- 1H MRS, proton magnetic resonance spectroscopy
- ADC, apparent diffusion coefficient
- ALF, acute liver failure
- AQP, aquaporins
- BBB, blood-brain barrier
- BDL, bile duct ligation
- CNS, central nervous system
- CSF, cerebrospinal fluid
- Cr, creatine
- DTI, diffusion tensor imaging
- DWI, diffusion-weighted imaging
- FLAIR, fluid-attenuated inversion recovery
- GM, gray matter
- Gln, glutamine
- Glx, sum of glutamine and glutamate
- HE, hepatic encephalopathy
- Ins, inositol
- LPS, lipopolysaccharide
- Lac, lactate
- MD, mean diffusivity
- MRI, magnetic resonance imaging
- MRS, magnetic resonance spectroscopy
- MT, magnetization transfer
- MTR, MT ratio
- NMR, nuclear magnetic resonance
- PCA, portocaval anastomosis
- TE, echo time
- WM, white matter
- brain edema
- chronic hepatic encephalopathy
- in vivo magnetic resonance imaging
- in vivo magnetic resonance spectroscopy
- liver cirrhosis
- mIns, myo-inositol
- tCho, total choline
- tCr, total creatine
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Affiliation(s)
- Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Simon D. Taylor-Robinson
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, St Mary's Hospital Campus, Imperial College London, London, United Kingdom
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19
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van Straten G, van Dalen D, Mesu SJ, Rothuizen J, Teske E, Spee B, Favier RP, van Geijlswijk IM. Efficacy of orally administered sodium benzoate and sodium phenylbutyrate in dogs with congenital portosystemic shunts. J Vet Intern Med 2019; 33:1331-1335. [PMID: 30916412 PMCID: PMC6524074 DOI: 10.1111/jvim.15477] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 02/25/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Hyperammonemia can result in hepatic encephalopathy, which in severe cases eventually can lead to coma and death. In dogs, congenital portosystemic shunts (CPSS) are the most common cause for hyperammonemia. Conservative treatment consists of a protein modified diet, nonabsorbable disaccharides, antibiotics, or some combinations of these. Sodium benzoate (SB) and sodium phenylbutyrate (SPB) both are used in the acute and long-term treatment of humans with hyperammonemia caused by urea cycle enzyme deficiencies. Both treatments are believed to lower blood ammonia concentrations by promoting excretion of excess nitrogen via alternative pathways. OBJECTIVES To evaluate the efficacy and safety of PO treatment with SB and SPB on hyperammonemia and clinical signs in CPSS dogs. METHODS Randomized, double-blind, placebo-controlled crossover trial. Concentrations of blood ammonia and bile acids were measured in CPSS dogs before and after a 5-day treatment with SB, SPB, and placebo. A wash-out period of 3 days was used between treatments. A standard questionnaire was developed and distributed to owners to evaluate clinical signs before and after each treatment. RESULTS Blood ammonia concentrations were not influenced by any of the treatments and were comparable to those observed during placebo treatment. In addition, SB and SPB treatment did not result in improvement of clinical signs. Adverse effects during treatment included anorexia, vomiting, and lethargy. CONCLUSIONS AND CLINICAL IMPORTANCE Based on our results, we conclude that SB or SPB are not useful in the conservative treatment of hyperammonemia in dogs with CPSS.
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Affiliation(s)
- Giora van Straten
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Diewke van Dalen
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Sietske J. Mesu
- Pharmacy Department, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Jan Rothuizen
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Erik Teske
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Bart Spee
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Robert P. Favier
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
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20
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Intravenous and Oral Hyperammonemia Management. CURRENT EMERGENCY AND HOSPITAL MEDICINE REPORTS 2018. [DOI: 10.1007/s40138-018-0174-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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21
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The Pharmabiotic Approach to Treat Hyperammonemia. Nutrients 2018; 10:nu10020140. [PMID: 29382084 PMCID: PMC5852716 DOI: 10.3390/nu10020140] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/22/2018] [Accepted: 01/26/2018] [Indexed: 12/12/2022] Open
Abstract
Ammonia is constantly produced as a metabolic waste from amino acid catabolism in mammals. Ammonia, the toxic waste metabolite, is resolved in the liver where the urea cycle converts free ammonia to urea. Liver malfunctions cause hyperammonemia that leads to central nervous system (CNS) dysfunctions, such as brain edema, convulsions, and coma. The current treatments for hyperammonemia, such as antibiotics or lactulose, are designed to decrease the intestinal production of ammonia and/or its absorption into the body and are not effective, besides being often accompanied by side effects. In recent years, increasing evidence has shown that modifications of the gut microbiota could be used to treat hyperammonemia. Considering the role of the gut microbiota and the physiological characteristics of the intestine, the removal of ammonia from the intestine by modulating the gut microbiota would be an ideal approach to treat hyperammonemia. In this review, we discuss the significance of hyperammonemia and its related diseases and the efficacy of the current management methods for hyperammonemia to understand the mechanism of ammonia transport in the human body. The possibility to use the gut microbiota as pharmabiotics to treat hyperammonemia and its related diseases is also explored.
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22
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Celik M, Akdeniz O, Ozgun N. Efficacy of peritoneal dialysis in neonates presenting with hyperammonaemia due to urea cycle defects and organic acidaemia. Nephrology (Carlton) 2018; 24:330-335. [PMID: 29356227 DOI: 10.1111/nep.13224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2018] [Indexed: 12/28/2022]
Abstract
AIM Newborns with inborn errors of metabolism can present with hyperammonaemic coma. In this study, we evaluated the effect of peritoneal dialysis on plasma ammonium levels and on the short-term outcome in neonatal patients with urea cycle defects and organic acidaemia. METHODS Data from infants with hyperammonaemia due to urea cycle defects or organic acidaemia treated with dialysis were collected and retrospectively analyzed. The results of patient groups (group I, survived; and group II, died) were compared. RESULTS Fourteen neonates were enrolled in this study. In group I, plasma ammonium levels before dialysis were median (IQR) 1652 μg/dL (1165-2098 μg/dL); in group II, they were 1289 μg/dL (1070-5550 μg/dL). There was no statistically significant difference. Urea cycle defects were diagnosed in eight, and organic acidaemia in six patients. The duration of a blood ammonia level >200 μg/dL was longer in group II (P = 0.04). A <60.8% decline in the ammonia level from the beginning of dialysis to the 12th hour of dialysis carried a 3.33-fold higher risk of mortality, when compared with a greater decline. Five patients with urea cycle defects, and one with organic acidaemia, died. The mortality risk was 8.33-fold (95% CI = 0.63-90.86) higher for patients with urea cycle defects than for those with organic acidaemia. CONCLUSION In patients with hyperammonaemia treated with peritoneal dialysis, the rate of ammonia removal and the underlying aetiology appear to be important prognostic factors. Neonates with organic acidaemia who are admitted to centres without continuous renal replacement therapy facilities can be effectively treated with peritoneal dialysis.
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Affiliation(s)
- Muhittin Celik
- Divisions of Neonatology, Diyarbakir Children's Hospital, Diyarbakir, Turkey
| | - Osman Akdeniz
- Divisions of Pediatric Cardiology, Diyarbakir Children's Hospital, Diyarbakir, Turkey
| | - Nezir Ozgun
- Divisions of Pediatric Neurology, Department of Pediatrics, Diyarbakir Children's Hospital, Diyarbakir, Turkey
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23
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Barkovich E, Robinson C, Gropman A. Brain biomarkers and neuroimaging to diagnose urea cycle disorders and assess prognosis. Expert Opin Orphan Drugs 2016. [DOI: 10.1080/21678707.2016.1242407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Clinical course of 63 patients with neonatal onset urea cycle disorders in the years 2001-2013. Orphanet J Rare Dis 2016; 11:116. [PMID: 27538463 PMCID: PMC4991093 DOI: 10.1186/s13023-016-0493-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 07/27/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Urea cycle disorders (UCDs) are rare inherited metabolic defects of ammonia detoxification. In about half of patients presenting with a UCD, the first symptoms appear within a few days after birth. These neonatal onset patients generally have a severe defect of urea cycle function and their survival and outcome prognoses are often limited. To understand better the current situation of neonatal onset in UCDs, we have performed a multicentre, retrospective, non-interventional case series study focussing on the most severe UCDs, namely defects of carbamoyl phosphate synthetase 1 (CPS1), ornithine transcarbamylase (OTC), and argininosuccinate synthetase (ASS). METHODS AND RESULTS Data of 63 patients were collected (27 patients with ASS deficiency, 23 patients with OTC deficiency, and 12 patients with CPS1 deficiency, one patient definite diagnosis not documented). The majority of patients (43/63, 68 %) had an initial ammonia concentration exceeding 500 μmol/L (normal < 100), of which most (26/43, 60.5 %) were also encephalopathic and were treated with hemodialysis. In patients surviving the initial crisis, recurrence of hyperammonemic events within the first 1.5 years of life occurred frequently (mean 3.6 events, range 0-20). Of all patients, 16 (25.4 %) died during or immediately after the neonatal period. CONCLUSION We observed in this cohort of neonatal onset UCD patients a high rate of initial life-threatening hyperammonemia and a high risk of recurrence of severe hyperammonemic crises. These corresponded to a high mortality rate during the entire study period (30.2 %) despite the fact that patients were treated in leading European metabolic centers. This underlines the need to critically re-evaluate the current treatment strategies in these patients.
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Garrido M, Skorucak J, Raduazzo D, Turco M, Spinelli G, Angeli P, Amodio P, Achermann P, Montagnese S. Vigilance and wake EEG architecture in simulated hyperammonaemia: a pilot study on the effects of L-Ornithine-L-Aspartate (LOLA) and caffeine. Metab Brain Dis 2016; 31:965-74. [PMID: 27193025 DOI: 10.1007/s11011-016-9835-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/10/2016] [Indexed: 12/21/2022]
Abstract
UNLABELLED Hyperammonaemia/mild hepatic encephalopathy (HE) can be simulated by the oral administration of a so-called amino acid challenge (AAC). This study sought to assess the effects of the AAC alone and in combination with either ammonia-lowering [L-ornithine-L-aspartate (LOLA)] or vigilance-enhancing medication (caffeine). Six patients with cirrhosis (5 males; 61.3 ± 9.2 years; 5 Child A, 1 Child B) and six healthy volunteers (5 males; 49.8 ± 10.6 years) were studied between 08:00 and 19:00 on Monday of three consecutive weeks. The following indices were obtained: hourly capillary ammonia, hourly subjective sleepiness, paper & pencil/computerized psychometry and wake electroencephalography (EEG) at 12:00, i.e. at the time of the maximum expected effect of the AAC. RESULTS On average, patients had worse neuropsychological performance and slower EEG than healthy volunteers in all conditions but differences did not reach significance. In healthy volunteers, the post-AAC increase in capillary ammonia levels was contained by both the administration of LOLA and of caffeine (significant differences between 10:00 and 14:00 h). The administration of caffeine also resulted in a reduction in subjective sleepiness and in the amplitude of the EEG on several frontal/temporal-occipital sites (p < 0.05; paired t-test). Changes in ammonia levels, subjective sleepiness and the EEG in the three conditions were less obvious in patients. In conclusion, both LOLA and caffeine contained the AAC-induced increase in capillary ammonia, especially in healthy volunteers. Caffeine also counteracted the AAC effects on sleepiness/EEG amplitude. The association of ammonia-lowering and vigilance-enhancing medication in the management of HE is worthy of further study.
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Affiliation(s)
- Maria Garrido
- Department of Medicine, University of Padua, Via Giustiniani, 2, 35128, Padova, Italy
| | - Jelena Skorucak
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
- Center for Interdisciplinary Sleep Research, University of Zurich, Zurich, Switzerland
| | - Daniela Raduazzo
- Department of Medicine, University of Padua, Via Giustiniani, 2, 35128, Padova, Italy
- USO Dipartimentale di Servizio Urgenza ed Emergenza Medica, ULSS 13, Dolo, Regione Veneto, Italy
| | - Matteo Turco
- Department of Medicine, University of Padua, Via Giustiniani, 2, 35128, Padova, Italy
| | - Giuseppe Spinelli
- Department of Medicine, University of Padua, Via Giustiniani, 2, 35128, Padova, Italy
- Department of Psychology, Sapienza University of Rome, Rome, Italy
| | - Paolo Angeli
- Department of Medicine, University of Padua, Via Giustiniani, 2, 35128, Padova, Italy
| | - Piero Amodio
- Department of Medicine, University of Padua, Via Giustiniani, 2, 35128, Padova, Italy
| | - Peter Achermann
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
- Center for Interdisciplinary Sleep Research, University of Zurich, Zurich, Switzerland
- Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Sara Montagnese
- Department of Medicine, University of Padua, Via Giustiniani, 2, 35128, Padova, Italy.
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Stoller F, Schlegel A, Viecelli HM, Rüfenacht V, Cesarovic N, Viecelli C, Deplazes S, Bettschart R, Hurter K, Schmierer P, Sidler X, Kron P, Dutkowski P, Graf R, Thöny B, Häberle J. Hepatocyte Transfection in Small Pigs After Weaning by Hydrodynamic Intraportal Injection of Naked DNA/Minicircle Vectors. Hum Gene Ther Methods 2015; 26:181-92. [DOI: 10.1089/hgtb.2014.140] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Fabienne Stoller
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland
| | - Andrea Schlegel
- Swiss HBP and Transplant Center, Department of Surgery, University Hospital Zürich, Zürich, Switzerland
| | - Hiu Man Viecelli
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland
| | - Véronique Rüfenacht
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland
| | - Nikola Cesarovic
- Division of Surgical Research, University Hospital Zürich, Zürich, Switzerland
| | - Claudio Viecelli
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland
| | - Sereina Deplazes
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland
| | - Regula Bettschart
- Department of Anaesthesia, Vetsuisse-Faculty University of Zürich, Zürich, Switzerland
| | - Karin Hurter
- Department of Small Animal Surgery, Vetsuisse-Faculty University of Zürich, Zürich, Switzerland
| | - Philipp Schmierer
- Department of Small Animal Surgery, Vetsuisse-Faculty University of Zürich, Zürich, Switzerland
| | - Xaver Sidler
- Departement für Nutztiere, Abteilung für Schweinemedizin, Vetsuisse-Fakultät, University of Zürich, Switzerland
| | - Philipp Kron
- Swiss HBP and Transplant Center, Department of Surgery, University Hospital Zürich, Zürich, Switzerland
| | - Philipp Dutkowski
- Swiss HBP and Transplant Center, Department of Surgery, University Hospital Zürich, Zürich, Switzerland
| | - Rolf Graf
- Swiss HBP and Transplant Center, Department of Surgery, University Hospital Zürich, Zürich, Switzerland
| | - Beat Thöny
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland
- Zürich Center for Integrative Human Physiology, Zürich, Switzerland
- Neuroscience Center Zürich, Zürich, Switzerland
| | - Johannes Häberle
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland
- Zürich Center for Integrative Human Physiology, Zürich, Switzerland
- Neuroscience Center Zürich, Zürich, Switzerland
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Kimoloi S, Rashid K. Potential role of Plasmodium falciparum-derived ammonia in the pathogenesis of cerebral malaria. Front Neurosci 2015; 9:234. [PMID: 26190968 PMCID: PMC4490226 DOI: 10.3389/fnins.2015.00234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 06/18/2015] [Indexed: 12/19/2022] Open
Abstract
Cerebral malaria (CM) is the most severe complication associated with Plasmodium falciparum infection. The exact pathogenic mechanisms leading to the development of CM remains poorly understood while the mortality rates remain high. Several potential mechanisms including mechanical obstruction of brain microvasculature, inflammation, oxidative stress, cerebral energy defects, and hemostatic dysfunction have been suggested to play a role in CM pathogenesis. However, these proposed mechanisms, even when considered together, do not fully explain the pathogenesis and clinicopathological features of human CM. This necessitates consideration of alternative pathogenic mechanisms. P. falciparum generates substantial amounts of ammonia as a catabolic by-product, but lacks detoxification mechanisms. Whether this parasite-derived ammonia plays a pathogenic role in CM is presently unknown, despite its potential to cause localized brain ammonia elevation and subsequent neurotoxic effects. This article therefore, explores and proposes a potential role of parasite-derived ammonia in the pathogenesis and neuropathology of CM. A consideration of parasite-derived ammonia as a factor in CM pathogenesis provides plausible explanations of the various features observed in CM patients including how a largely intravascular parasite can cause neuronal dysfunction. It also provides a framework for rational development and testing of novel drugs targeting the parasite's ammonia handling.
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Affiliation(s)
- Sammy Kimoloi
- Department of Medical Laboratory Sciences, Masinde Muliro University of Science and Technology Kakamega, Kenya
| | - Khalid Rashid
- Biochemistry and Molecular Biology Department, Egerton University Nakuru, Kenya
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Kromas ML, Mousa OY, John S. Hyperammonemia-induced encephalopathy: A rare devastating complication of bariatric surgery. World J Hepatol 2015; 7:1007-1011. [PMID: 25954483 PMCID: PMC4419094 DOI: 10.4254/wjh.v7.i7.1007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/26/2015] [Accepted: 03/18/2015] [Indexed: 02/06/2023] Open
Abstract
The clinical manifestations of hyperammonemia are usually easily identifiable to the clinician when associated with liver disease and lead to prompt diagnosis and treatment. However, hyperammonemia-induced encephalopathy is rare in adults in the absence of overt liver disease, thus diagnosis is often delayed or missed leading to potentially life threatening complications. Without proper treatment, such patients can decompensate rapidly with poor outcomes including seizures, coma, and death. Early assessment of plasma ammonia levels in patients with normal hepatic function and characteristic symptoms of encephalopathy can lead to early intervention while investigating the underlying etiology. We describe a patient who presented with a 2-year progression of waxing and waning acute mental status changes after a Roux-en-Y gastric bypass surgery. He was found to have elevated ammonia level as well as orotic aciduria; results consistent with a urea cycle disorder. After consulting neurology as well as toxicology, he ultimately improved after dietary protein restriction, sodium benzoate and lactulose therapy. While rare, clinicians should have a high index of suspicion for late onset urea cycle disorders in symptomatic patients presenting with encephalopathy secondary to hyperammonemia.
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Prado FA, Delfino VDA, Grion CMC, de Oliveira JA. Hyperammonemia in ICU patients: a frequent finding associated with high mortality. J Hepatol 2015; 62:1216-8. [PMID: 25617506 DOI: 10.1016/j.jhep.2015.01.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 01/05/2015] [Accepted: 01/07/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Fabrizio A Prado
- Department of Internal Medicine, Londrina State University, Rua João Wycliff, 405, Londrina, PR, Brazil.
| | - Vinicius D A Delfino
- Department of Internal Medicine, Londrina State University, Rua Walter Motta Campos 293, Londrina, PR, Brazil
| | - Cintia M C Grion
- Department of Internal Medicine, Londrina State University, Rua Vila. Lobos 580, Londrina, PR, Brazil
| | - Jair A de Oliveira
- Department of Pathology, Clinical Analysis and Toxicology, Londrina State University, Avenida do Café 655, Londrina, PR, Brazil
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Tapper EB, Jiang ZG, Patwardhan VR. Refining the ammonia hypothesis: a physiology-driven approach to the treatment of hepatic encephalopathy. Mayo Clin Proc 2015; 90:646-58. [PMID: 25865476 DOI: 10.1016/j.mayocp.2015.03.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 02/27/2015] [Accepted: 03/03/2015] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is one of the most important complications of cirrhosis and portal hypertension. Although the etiology is incompletely understood, it has been linked to ammonia directly and indirectly. Our goal is to review for the clinician the mechanisms behind hyperammonemia and the pathogenesis of HE to explain the rationale for its therapy. We reviewed articles collected through a search of MEDLINE/PubMed, Cochrane Database of Systematic Reviews, and Google Scholar between October 1, 1948, and December 8, 2014, and by a manual search of citations within retrieved articles. Search terms included hepatic encephalopathy, ammonia hypothesis, brain and ammonia, liver failure and ammonia, acute-on-chronic liver failure and ammonia, cirrhosis and ammonia, portosytemic shunt, ammonia and lactulose, rifaximin, zinc, and nutrition. Ammonia homeostatsis is a multiorgan process involving the liver, brain, kidneys, and muscle as well as the gastrointestinal tract. Indeed, hyperammonemia may be the first clue to poor functional reserves, malnutrition, and impending multiorgan dysfunction. Furthermore, the neuropathology of ammonia is critically linked to states of systemic inflammation and endotoxemia. Given the complex interplay among ammonia, inflammation, and other factors, ammonia levels have questionable utility in the staging of HE. The use of nonabsorbable disaccharides, antibiotics, and probiotics reduces gut ammoniagenesis and, in the case of antibiotics and probiotics, systemic inflammation. Nutritional support preserves urea cycle function and prevents wasting of skeletal muscle, a significant site of ammonia metabolism. Correction of hypokalemia, hypovolemia, and acidosis further assists in the reduction of ammonia production in the kidney. Finally, early and aggressive treatment of infection, avoidance of sedatives, and modification of portosystemic shunts are also helpful in reducing the neurocognitive effects of hyperammonemia. Refining the ammonia hypothesis to account for these other factors instructs a solid foundation for the effective treatment and prevention of hepatic encephalopathy.
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Affiliation(s)
- Elliot B Tapper
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA.
| | - Z Gordon Jiang
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA
| | - Vilas R Patwardhan
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA
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Casula EP, Bisiacchi PS, Corrias M, Schiff S, Merkel C, Amodio P, Montagnese S. Acute hyperammonaemia induces a sustained decrease in vigilance, which is modulated by caffeine. Metab Brain Dis 2015; 30:143-9. [PMID: 25052067 DOI: 10.1007/s11011-014-9590-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 07/07/2014] [Indexed: 01/29/2023]
Abstract
UNLABELLED Hyperammonaemia is observed after prolonged, intense exercise, or in patients with hepatic failure. In the latter, it is associated with a set of neurological and psychiatric abnormalities termed hepatic encephalopathy. THE AIMS OF OUR STUDY WERE 1. to measure vigilance in a condition of induced hyperammonaemia; 2. to assess whether caffeine modulates the effects of hyperammonaemia on vigilance, if any. Ten healthy volunteers (28.5 ± 5 years; 5 males) underwent three experimental sessions consisting of two-hourly measurements of capillary ammonia, subjective sleepiness (Karolinska Sleepiness Scale) and vigilance (Psychomotor Vigilance Task, PVT), in relation to the intake of breakfast (+/-coffee), an amino acid mixture which induces hyperammonaemia (amino acid challenge; AAC), and AAC+coffee (only for participants who had coffee with their standard breakfast). The AAC resulted in: 1. the expected increase in capillary ammonia levels, with highest values at approximately 4 h after the administration; 2. a significant increase in subjective sleepiness ratings; 3. a sustained increase in PVT-based reaction times. When caffeine was administered after the AAC, both subjective sleepiness and the slowing in RTs were significantly milder than in the AAC-only condition. In conclusion, acute hyperammonaemia induces an increase in subjective sleepiness and a sustained decrease in vigilance, which are attenuated by the administration of a single espresso coffee.
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Affiliation(s)
- E P Casula
- Department of Medicine, University of Padova, Via Giustiniani, 2, 35128, Padova, Italy
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Abstract
Human adults produce around 1000 mmol of ammonia daily. Some is reutilized in biosynthesis. The remainder is waste and neurotoxic. Eventually most is excreted in urine as urea, together with ammonia used as a buffer. In extrahepatic tissues, ammonia is incorporated into nontoxic glutamine and released into blood. Large amounts are metabolized by the kidneys and small intestine. In the intestine, this yields ammonia, which is sequestered in portal blood and transported to the liver for ureagenesis, and citrulline, which is converted to arginine by the kidneys. The amazing developments in NMR imaging and spectroscopy and molecular biology have confirmed concepts derived from early studies in animals and cell cultures. The processes involved are exquisitely tuned. When they are faulty, ammonia accumulates. Severe acute hyperammonemia causes a rapidly progressive, often fatal, encephalopathy with brain edema. Chronic milder hyperammonemia causes a neuropsychiatric illness. Survivors of severe neonatal hyperammonemia have structural brain damage. Proposed explanations for brain edema are an increase in astrocyte osmolality, generally attributed to glutamine accumulation, and cytotoxic oxidative/nitrosative damage. However, ammonia neurotoxicity is multifactorial, with disturbances also in neurotransmitters, energy production, anaplerosis, cerebral blood flow, potassium, and sodium. Around 90% of hyperammonemic patients have liver disease. Inherited defects are rare. They are being recognized increasingly in adults. Deficiencies of urea cycle enzymes, citrin, and pyruvate carboxylase demonstrate the roles of isolated pathways in ammonia metabolism. Phenylbutyrate is used routinely to treat inherited urea cycle disorders, and its use for hepatic encephalopathy is under investigation.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
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Pacheco-Colón I, Fricke S, VanMeter J, Gropman AL. Advances in urea cycle neuroimaging: Proceedings from the 4th International Symposium on urea cycle disorders, Barcelona, Spain, September 2013. Mol Genet Metab 2014; 113:118-26. [PMID: 25066103 PMCID: PMC4177962 DOI: 10.1016/j.ymgme.2014.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 05/10/2014] [Indexed: 11/20/2022]
Abstract
Our previous imaging research performed as part of a Urea Cycle Rare Disorders Consortium (UCRDC) grant, has identified specific biomarkers of neurologic injury in ornithine transcarbamylase deficiency, OTCD. While characterization of mutations can be achieved in most cases, this information does not necessarily predict the severity of the underlying neurological syndrome. The biochemical consequences of any mutation may be modified additionally by a large number of factors, including contributions of other enzymes and transport systems that mediate flux through the urea cycle, diet and other environmental factors. These factors likely vary from one patient to another, and they give rise to heterogeneity of clinical severity. Affected cognitive domains include non-verbal learning, fine motor processing, reaction time, visual memory, attention, and executive function. Deficits in these capacities may be seen in symptomatic patients, as well as asymptomatic carriers with normal IQ and correlate with variances in brain structure and function in these patients. Using neuroimaging we can identify biomarkers that reflect the downstream impact of UCDs on cognition. This manuscript is a summary of the presentation from the 4th International Consortium on urea cycle disorders held in, Barcelona, Spain, September 2, 2014.
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Affiliation(s)
| | - Stanley Fricke
- Children's National Medical, USA; George Washington University, USA
| | - John VanMeter
- Center for Functional and Molecular Imaging, Georgetown University, USA
| | - Andrea L Gropman
- Center for Functional and Molecular Imaging, Georgetown University, USA; Children's National Medical, USA; George Washington University, USA.
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Inokuchi R, Nakamura K, Mizuno N, Sato H, Shinohara K, Matsubara T, Doi K, Ishii T, Gunshin M, Nakajima S, Yahagi N. Adult-onset seizures in a patient with Down syndrome and portosystemic shunt. Brain Dev 2014; 36:626-9. [PMID: 24035599 DOI: 10.1016/j.braindev.2013.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 07/31/2013] [Accepted: 08/06/2013] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The prevalence of epilepsy in patients with Down syndrome (DS) is 5-13%, which is higher than the prevalence in the general population. Transient hyperammonemia is often observed following seizure, but it typically resolves within a day. Here, we describe the case a 37-year-old woman who had DS and a history of adult-onset epilepsy and was admitted to our hospital with recurrent seizures. After admission, her ammonia levels fluctuated without any apparent cause, and dynamic computed tomography revealed a portosystemic shunt. The findings suggest that her seizures possibly precipitated from hyperammonemia secondary to a portosystemic shunt, and we reviewed the relevant literature. METHODS We conducted PubMed, Web of Science, and EMBASE searches without language restrictions for articles published between 1970 and February 2013. RESULTS In addition to the present case, 7 cases were ultimately included in this review. Four patients were newborns, 2 patients were 1 month old, and 1 patient was 3 years old. No adult cases were described until now. CONCLUSION Adult patients with DS diagnosed with epilepsy are not routinely assessed for portosystemic venous shunts. Measuring ammonia levels in patients with DS the day after admission would help detect portosystemic shunts, even if the patients have been previously diagnosed with epilepsy. PRACTICE IMPLICATIONS If ammonia levels fluctuate without any apparent cause after seizure, dynamic computed tomography should be performed, especially for patients with DS, whether or not they have been previously diagnosed with epilepsy.
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Affiliation(s)
- Ryota Inokuchi
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan.
| | - Kensuke Nakamura
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan
| | - Naoaki Mizuno
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan
| | - Hajime Sato
- Department of Health Policy and Technology Assessment, National Institute of Public Health, Japan
| | - Kazuaki Shinohara
- Department of Emergency and Critical Care Medicine, Ohta Nishinouchi Hospital, Japan
| | - Takehiro Matsubara
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan
| | - Kent Doi
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan
| | - Takeshi Ishii
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan
| | - Masataka Gunshin
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan
| | - Susumu Nakajima
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan
| | - Naoki Yahagi
- Department of Emergency and Critical Care Medicine, The University of Tokyo Hospital, Japan
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36
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Bergmann KR, McCabe J, Smith TR, Guillaume DJ, Sarafoglou K, Gupta S. Late-onset ornithine transcarbamylase deficiency: treatment and outcome of hyperammonemic crisis. Pediatrics 2014; 133:e1072-6. [PMID: 24616362 DOI: 10.1542/peds.2013-1324] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Hyperammonemic crises in ornithine transcarbamylase deficiency (OTC) can be associated with devastating cerebral edema resulting in severe long-term neurologic impairment and death. We present an 8-year-old boy who had late-onset OTC deficiency in which early and aggressive management of hyperammonemia and associated cerebral edema, including therapeutic hypothermia and barbiturate-induced coma, resulted in favorable neurologic outcome. Our patient presented with vomiting and altered mental status, and was found to have a significantly elevated serum ammonia level of 1561 μmol/L. Hyperammonemia was managed with hemodialysis, 10% sodium phenylacetate, 10% sodium benzoate, L-arginine, intravenous 10% dextrose, intralipids, and protein restriction. He developed significant cerebral edema with intracranial pressures >20 mm Hg, requiring treatment with 3% saline and mannitol. Despite this treatment our patient continued to have elevated intracranial pressures, which were treated aggressively with non-conventional modalities including therapeutic hypothermia, barbiturate-induced coma, and external ventricular drainage. This therapy resulted in stabilization of hyperammonemia and resolution of cerebral edema. Molecular testing later revealed a hemizygous mutation within the OTC gene. Neuropsychological testing 1 year after discharge showed normal intelligence with no visual-motor deficits, minor deficits in working memory and processing speed, and slightly below average processing speed and executive functioning.
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Oh MY, Lee BS, Oh SH, Jang HJ, Do HJ, Kim EAR, Kim KS, Lee JH, Park YS, Lee BH, Yoo HW. Continuous Renal Replacement Therapy in the Neonatal Intensive Care Unit: A Single-Center Study. NEONATAL MEDICINE 2014. [DOI: 10.5385/nm.2014.21.4.244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- Moon-yeon Oh
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Byong Sop Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Seong-Hee Oh
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Hee Jin Jang
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyun-Jeong Do
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Ellen Ai-Rhan Kim
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Ki-Soo Kim
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Joo Hoon Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Young Seo Park
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Beom-Hee Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Han-Wook Yoo
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
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Braissant O, McLin VA, Cudalbu C. Ammonia toxicity to the brain. J Inherit Metab Dis 2013; 36:595-612. [PMID: 23109059 DOI: 10.1007/s10545-012-9546-2] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 09/19/2012] [Accepted: 09/25/2012] [Indexed: 12/21/2022]
Abstract
Hyperammonemia can be caused by various acquired or inherited disorders such as urea cycle defects. The brain is much more susceptible to the deleterious effects of ammonium in childhood than in adulthood. Hyperammonemia provokes irreversible damage to the developing central nervous system: cortical atrophy, ventricular enlargement and demyelination lead to cognitive impairment, seizures and cerebral palsy. The mechanisms leading to these severe brain lesions are still not well understood, but recent studies show that ammonium exposure alters several amino acid pathways and neurotransmitter systems, cerebral energy metabolism, nitric oxide synthesis, oxidative stress and signal transduction pathways. All in all, at the cellular level, these are associated with alterations in neuronal differentiation and patterns of cell death. Recent advances in imaging techniques are increasing our understanding of these processes through detailed in vivo longitudinal analysis of neurobiochemical changes associated with hyperammonemia. Further, several potential neuroprotective strategies have been put forward recently, including the use of NMDA receptor antagonists, nitric oxide inhibitors, creatine, acetyl-L-carnitine, CNTF or inhibitors of MAPKs and glutamine synthetase. Magnetic resonance imaging and spectroscopy will ultimately be a powerful tool to measure the effects of these neuroprotective approaches.
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Affiliation(s)
- Olivier Braissant
- Service of Biomedicine, Lausanne University Hospital, Avenue Pierre-Decker 2, CI 02/33, CH-1011 Lausanne, Switzerland.
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Abstract
N-acetyl-glutamate synthase (NAGS) deficiency is a rare autosomal recessive urea cycle disorder (UCD) that uncommonly presents in adulthood. Adult presentations of UCDs include; confusional episodes, neuropsychiatric symptoms and encephalopathy. To date, there have been no detailed neurological descriptions of an adult onset presentation of NAGS deficiency. In this review we examine the clinical presentation and management of UCDs with an emphasis on NAGS deficiency. An illustrative case is provided. Plasma ammonia levels should be measured in all adult patients with unexplained encephalopathy, as treatment can be potentially life-saving. Availability of N-carbamylglutamate (NCG; carglumic acid) has made protein restriction largely unnecessary in treatment regimens currently employed. Genetic counselling remains an essential component of management of NAGS.
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40
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Mehta N, Kirk PC, Holder R, Precheur HV. Urea cycle disorder--argininosuccinic lyase deficiency. SPECIAL CARE IN DENTISTRY 2013; 32:155-9. [PMID: 22784324 DOI: 10.1111/j.1754-4505.2012.00263.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An increased level of ammonia in the bloodstream, or hyperammonemia, is a symptom associated with metabolic disorders referred to as inborn errors of metabolism. Urea cycle disorder is a congenital abnormality or absence of one of the six enzymes involved in the elimination of ammonia. Administration of certain medications, high protein diet, excessive exercise, surgical procedures, or trauma can precipitate symptoms of mental confusion, seizure-like activity, and ataxia. This paper reviews the literature with insight into current treatment and management options of the disorder and modification of treatment for the dental patient.
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Affiliation(s)
- Neeta Mehta
- Department of Advanced Dentistry, School of Dentistry, University of Mississippi, Jackson, Mississippi, USA.
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Seeliger C, Culmes M, Schyschka L, Yan X, Damm G, Wang Z, Kleeff J, Thasler WE, Hengstler J, Stöckle U, Ehnert S, Nüssler AK. Decrease of global methylation improves significantly hepatic differentiation of Ad-MSCs: possible future application for urea detoxification. Cell Transplant 2012; 22:119-31. [PMID: 22507189 DOI: 10.3727/096368912x638946] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Hepatocyte transplantation is considered to be an alternative to orthotopic liver transplantation. Cells can be used to bridge patients waiting for a donor organ, decrease mortality in acute liver failure, and support metabolic liver diseases. The limited availability of primary human hepatocytes for such applications has led to the generation of alternative hepatocyte-like cells from various adult stem or precursor cells. The aim of this study was to generate hepatocyte-like cells from adipose-derived mesenchymal stem cells (Ad-MSCs) for clinical applications, which are available "off the shelf." Epigenetic changes in hepatocyte-like cells were induced by 5-azacytidine, which, in combination with other supplements, leads to significantly improved metabolic and enzymatic activities compared to nontreated cells. Cells with sufficient hepatic features were generated with a four-step protocol: 5-azacytidine (step 1); epidermal growth factor (step 2); fibroblast growth factor-4, dexamethasone, insulin-transferrin-sodium-selenite, and nicotinamide (step 3); and hepatocyte growth factor, dexamethasone, insulin-transferrin-sodium-selenite, and nicotinamide (step 4). Generated differentiated cells had higher phase I (CYP1A1/2, CYP2E1, CYP2B6, CYP3A4) and phase II activities compared to the undifferentiated cells. A strong expression of CYP3A7 and a weak expression of 3A4, as well as the important detoxification markers α-fetoprotein and albumin, could also be detected at the mRNA level. Importantly, urea metabolism (basal, NH4-stimulated, NH4- and ornithine-stimulated) was comparable to freshly isolated human hepatocytes, and unlike cryopreserved human hepatocytes, this activity was maintained after 6 months of cryopreservation. These findings suggest that these cells may be suitable for clinical application, especially for treatment of urea cycle disorders.
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Affiliation(s)
- C Seeliger
- Technical University Munich, MRI, Department of Trauma Surgery, Germany
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42
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Weber RA, Maceira JJP, Mancebo MJ, Peleteiro JB, Martín LOG, Aldegunde M. Effects of acute exposure to exogenous ammonia on cerebral monoaminergic neurotransmitters in juvenile Solea senegalensis. ECOTOXICOLOGY (LONDON, ENGLAND) 2012; 21:362-369. [PMID: 21971970 DOI: 10.1007/s10646-011-0797-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/19/2011] [Indexed: 05/31/2023]
Abstract
The present study explored the potential role of brain catecholaminergic and serotoninergic systems as neuronal targets for the toxicological effects of acute ammonia exposure (0.28 mg l(-1) of un-ionized ammonia for 12 and 24 h) in juvenile sole (Solea senegalensis). In addition, plasma cortisol levels were measured. The results showed significant increases in their concentrations that were similar after 12 and 24 h of exposure. These data indicate that acute exposure (12 and 24 h) to ammonia initiates a typical stress response in the Senegalese sole, with stimulation of the hypothalamus-pituitary-interrenal axis. The concentrations of dopamine (DA), serotonin (5-hydroxytryptamine; 5-HT) and noradrenaline (NA), and their metabolites, 3, 4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxy-3-indoleacetic acid (5HIAA), were measured in the hypothalamus, telencephalon and optic tectum. The main changes induced by acute exposure to ammonia were decreases in the concentrations of 5-HT and DA, which were significant in most of the brain regions studied. The ratios of 5-HIAA/5-HT and DOPAC/DA increased in all regions and at all times studied, although in the case of the DOPAC/DA ratio, the increases were only significant in the hypothalamus (24 h exposure) and in the optic tectum (12 and 24 h exposure). These changes indicated that exposure to ammonia elicited time-dependent increases in serotoninergic and dopaminergic activity in the hypothalamus, telencephalon and optic tectum.
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Affiliation(s)
- R A Weber
- Departamento de Fisiología, Facultad de Biología, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
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Abstract
Ammonia is produced continuously in the body. It crosses the blood-brain barrier readily and at increased concentration it is toxic to the brain. A highly integrated system protects against this: ammonia produced during metabolism is detoxified temporarily by incorporation into the non-toxic amino acid glutamine. This is transported safely in the circulation to the small intestine, where ammonia is released, carried directly to the liver in the portal blood, converted to non-toxic urea and finally excreted in urine. As a result, plasma concentrations of ammonia in the systemic circulation are normally very low (<40 μmol/L). Hyperammonaemia develops if the urea cycle cannot control the ammonia load. This occurs when the load is excessive, portal blood from the intestines bypasses the liver and/or the urea cycle functions poorly. By far, the commonest cause is liver damage. This review focuses on other causes in adults. Because they are much less common, the diagnosis may be missed or delayed, with disastrous consequences. There is effective treatment for most of them, but it must be instituted promptly to avoid fatality or long-term neurological damage. Of particular concern are unsuspected inherited defects of the urea cycle and fatty acid oxidation presenting with catastrophic illness in previously normal individuals. Early identification of the problem is the challenge.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, C Level MP 8, South Block, Southampton Hospital, Tremona Road, Southampton SO16 6YD, UK.
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Hyperammonemia in review: pathophysiology, diagnosis, and treatment. Pediatr Nephrol 2012; 27:207-22. [PMID: 21431427 DOI: 10.1007/s00467-011-1838-5] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 01/09/2011] [Accepted: 01/12/2011] [Indexed: 12/31/2022]
Abstract
Ammonia is an important source of nitrogen and is required for amino acid synthesis. It is also necessary for normal acid-base balance. When present in high concentrations, ammonia is toxic. Endogenous ammonia intoxication can occur when there is impaired capacity of the body to excrete nitrogenous waste, as seen with congenital enzymatic deficiencies. A variety of environmental causes and medications may also lead to ammonia toxicity. Hyperammonemia refers to a clinical condition associated with elevated ammonia levels manifested by a variety of symptoms and signs, including significant central nervous system (CNS) abnormalities. Appropriate and timely management requires a solid understanding of the fundamental pathophysiology, differential diagnosis, and treatment approaches available. The following review discusses the etiology, pathogenesis, differential diagnosis, and treatment of hyperammonemia.
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Kasai A, Nagao K, Kikushima K, Watanabe K, Tachibana E, Soga T, Mastsuzaki M, Yagi T. Prognostic Value of Venous Blood Ammonia in Patients With Out-of-Hospital Cardiac Arrest. Circ J 2012; 76:891-9. [DOI: 10.1253/circj.cj-11-0449] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Asuka Kasai
- Department of Emergency Care, Surugadai Nihon University Hospital
| | - Ken Nagao
- Department of Cardiology, Resuscitation and Emergency Cardiovascular Care, Surugadai Nihon University Hospital
| | - Kimio Kikushima
- Department of Cardiology, Resuscitation and Emergency Cardiovascular Care, Surugadai Nihon University Hospital
| | - Kazuhiro Watanabe
- Department of Cardiology, Resuscitation and Emergency Cardiovascular Care, Surugadai Nihon University Hospital
| | - Eizo Tachibana
- Department of Cardiology, Resuscitation and Emergency Cardiovascular Care, Surugadai Nihon University Hospital
| | - Taketomo Soga
- Department of Cardiology, Resuscitation and Emergency Cardiovascular Care, Surugadai Nihon University Hospital
| | - Masakazu Mastsuzaki
- Department of Cardiology, Resuscitation and Emergency Cardiovascular Care, Surugadai Nihon University Hospital
| | - Tsukasa Yagi
- Department of Cardiology, Resuscitation and Emergency Cardiovascular Care, Surugadai Nihon University Hospital
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Prust MJ, Gropman AL, Hauser N. New frontiers in neuroimaging applications to inborn errors of metabolism. Mol Genet Metab 2011; 104:195-205. [PMID: 21778100 PMCID: PMC3758691 DOI: 10.1016/j.ymgme.2011.06.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Revised: 06/25/2011] [Accepted: 06/26/2011] [Indexed: 12/21/2022]
Abstract
Most inborn errors of metabolism (IEMs) are associated with potential for injury to the developing central nervous system resulting in chronic encephalopathy, though the etiopathophysiology of neurological injury have not been fully established in many disorders. Shared mechanisms can be envisioned such as oxidative injury due to over-activation of N-Methyl-d-Aspartate (NMDA) receptors with subsequent glutamatergic damage, but other causes such as energy depletion or inflammation are possible. Neuroimaging has emerged as a powerful clinical and research tool for studying the brain in a noninvasive manner. Several platforms exist to study neural networks underlying cognitive processes, white matter/myelin microstructure, and cerebral metabolism in vivo. The scope and limitations of these methods will be discussed in the context of valuable information they provide in the study and management of selected inborn errors of metabolism. This review is not meant to be an exhaustive coverage of diagnostic findings on MRI in multiple IEMs, but rather to illustrate how neuroimaging modalities beyond T1 and T2 images, can add depth to an understanding of the underlying brain changes evoked by the selected IEMs. Emphasis will be placed on techniques that are available in the clinical setting. Though technically complex, many of these modalities have moved - or soon will - to the clinical arena.
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Affiliation(s)
- Morgan J. Prust
- Department of Neurology, Children’s National Medical Center, Washington, D.C., USA
| | - Andrea L. Gropman
- Department of Neurology, Children’s National Medical Center, Washington, D.C., USA
- Medical Genetics Branch, National Human Genome Research Institute, USA
- Corresponding author at: Department of Neurology, Children’s National Medical Center, 111 Michigan Avenue, N.W., Washington, D.C. 20010, USA. Fax: +1 202 476 5226. (A.L. Gropman)
| | - Natalie Hauser
- Medical Genetics Branch, National Human Genome Research Institute, USA
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47
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Clinical practice: the management of hyperammonemia. Eur J Pediatr 2011; 170:21-34. [PMID: 21165747 DOI: 10.1007/s00431-010-1369-2] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/22/2010] [Accepted: 11/24/2010] [Indexed: 01/25/2023]
Abstract
Hyperammonemia is a life-threatening condition which can affect patients at any age. Elevations of ammonia in plasma indicate its increased production and/or decreased detoxification. The hepatic urea cycle is the main pathway to detoxify ammonia; it can be defective due to an inherited enzyme deficiency or secondary to accumulated toxic metabolites or substrate depletion. Clinical signs and symptoms in hyperammonemia are unspecific but they are mostly neurological. Thus, in any unexplained change in consciousness or in any unexplained encephalopathy, hyperammonemia must be excluded as fast as possible. Any delay in recognition and start of treatment of hyperammonemia may have deleterious consequences for the patient. Treatment largely depends on the underlying cause but is, at least in pediatric patients, mainly aimed at establishing anabolism to avoid endogenous protein breakdown and amino acid imbalances. In addition, pharmacological treatment options exist to improve urea cycle function or to remove nitrogen, but their use depend on the underlying disorder. To improve the prognosis of acute hyperammonemia, an increased awareness of this condition is probably more needed than anything else. Likewise, the immediate start of appropriate therapy is of utmost importance. This review focuses on a better understanding of factors leading to ammonia elevations and on practical aspects related to diagnosis and treatment in order to improve clinical management of hyperammonemia.
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48
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Continuous hemofiltration in the control of neonatal hyperammonemia: a 10-year experience. Pediatr Nephrol 2010; 25:1725-30. [PMID: 20495829 DOI: 10.1007/s00467-010-1549-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Revised: 03/07/2010] [Accepted: 03/30/2010] [Indexed: 12/31/2022]
Abstract
In a 10-year review of the utilization of continuous veno-venous hemofiltration (CVVH) for the treatment of neonatal hyperammonemia, 14 patients were identified with hyperammonemia due to either a urea cycle defect or an organic acidemia. Intensive care survival was 64%. The pretreatment level of serum ammonia and the rapidity of ammonia clearance did not differ between survivors and non-survivors (p = 0.16 and p = 0.93, respectively). Likewise, the duration of CVVH therapy did not differ between survivors and non-survivors (p = 0.1). Indicators of pretreatment physiological stress showed either a correlation with non-survival [Pediatric Risk of Mortality (PRISM) score, p = 0.006, cardioactive drug requirement, p = 0.003], or demonstrated a trend to such a correlation (serum lactate, p = 0.06). Complications associated with the CVVH technique were infrequent. Hypotension was seen in seven patients, but in only one patient did it arise de novo following the initiation of CVVH. In conclusion, neither the severity of the hyperammonemic state nor the efficacy of ammonia removal correlated with patient outcome. The pre-CVVH PRISM score and requirement for cardio-active medication were significantly greater in those patients who did not survive their acute illness. The pre-CVVH physiological condition of the neonates in this cohort was the main determinant of outcome.
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Outpatient treatment of propionic acidemia-associated hyperammonemia with N-carbamoyl-l-glutamate in an infant. Clin Ther 2010; 32:710-3. [DOI: 10.1016/j.clinthera.2010.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2010] [Indexed: 11/20/2022]
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50
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Langer JE, Wilson WG, Raghavan P, Rust RS, Goodkin HP. Extrapontine myelinolysis resulting in transient cortical blindness. Pediatr Neurol 2010; 42:154-6. [PMID: 20117757 DOI: 10.1016/j.pediatrneurol.2009.08.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 08/21/2009] [Accepted: 08/28/2009] [Indexed: 11/25/2022]
Abstract
Central pontine myelinolysis and extrapontine myelinolysis are characterized by symmetric demyelination subsequent to rapid shifts in serum osmolality. Described here is a novel case of transient cortical blindness in association with imaging features of extrapontine myelinolysis, which occurred in a child with carbamoyl phosphate synthetase deficiency after rapid correction of hyperammonemia. Serum sodium levels were within normal limits at presentation and throughout the period of ammonia correction. A potential pathogenic mechanism of osmotic demyelination in the setting of acute treatment for hyperammonemia in a patient with a urea cycle abnormality includes disruption of the blood-brain barrier and re-equilibration of organic osmolytes, particularly glutamine.
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Affiliation(s)
- Jennifer E Langer
- Department of Neurology, University of Virginia Health System, Charlottesville, Virginia, USA
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