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Abstract
BACKGROUND Hyperammonemia is an adverse effect that poses clinical uncertainty around valproic acid (VPA) use. The prevalence of symptomatic and asymptomatic hyperammonemia and its relationship to VPA concentration is not well established. There is also no clear guidance regarding its management. This results in variability in the monitoring and treatment of VPA-induced hyperammonemia. To inform clinical practice, this systematic review aims to summarize evidence available around VPA-associated hyperammonemia and its prevalence, clinical outcomes, and management. METHODS An electronic search was performed through Ovid MEDLINE, Ovid Embase, Web of Science, and PsycINFO using search terms that identified hyperammonemia in patients receiving VPA. Two reviewers independently performed primary title and abstract screening with a third reviewer resolving conflicting screening results. This process was repeated during the full-text review process. RESULTS A total of 240 articles were included. Prevalence of asymptomatic hyperammonemia (5%-73%) was higher than symptomatic hyperammonemia (0.7%-22.2%) and occurred within the therapeutic range of VPA serum concentration. Various risk factors were identified, including concomitant medications, liver injury, and defects in carnitine metabolism. With VPA discontinued, most symptomatic patients returned to baseline mental status with normalized ammonia level. There was insufficient data to support routine monitoring of ammonia level for VPA-associated hyperammonemia. CONCLUSIONS Valproic acid-associated hyperammonemia is a common adverse effect that may occur within therapeutic range of VPA. Further studies are required to determine the benefit of routine ammonia level monitoring and to guide the management of VPA-associated hyperammonemia.
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Affiliation(s)
- Yiu-Ching Jennifer Wong
- From the Department of Pharmacy, St Paul's Hospital; and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
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Sen K, Whitehead M, Castillo Pinto C, Caldovic L, Gropman A. Fifteen years of urea cycle disorders brain research: Looking back, looking forward. Anal Biochem 2022; 636:114343. [PMID: 34637785 PMCID: PMC8671367 DOI: 10.1016/j.ab.2021.114343] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/13/2021] [Accepted: 08/17/2021] [Indexed: 01/03/2023]
Abstract
Urea cycle disorders (UCD) are inherited diseases resulting from deficiency in one of six enzymes or two carriers that are required to remove ammonia from the body. UCD may be associated with neurological damage encompassing a spectrum from asymptomatic/mild to severe encephalopathy, which results in most cases from Hyperammonemia (HA) and elevation of other neurotoxic intermediates of metabolism. Electroencephalography (EEG), Magnetic resonance imaging (MRI) and Proton Magnetic resonance spectroscopy (MRS) are noninvasive measures of brain function and structure that can be used during HA to guide management and provide prognostic information, in addition to being research tools to understand the pathophysiology of UCD associated brain injury. The Urea Cycle Rare disorders Consortium (UCDC) has been invested in research to understand the immediate and downstream effects of hyperammonemia (HA) on brain using electroencephalogram (EEG) and multimodal brain MRI to establish early patterns of brain injury and to track recovery and prognosis. This review highlights the evolving knowledge about the impact of UCD and HA in particular on neurological injury and recovery and use of EEG and MRI to study and evaluate prognostic factors for risk and recovery. It recognizes the work of others and discusses the UCDC's prior work and future research priorities.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Neurodevelopmental Pediatrics, Children's National Hospital, Washington D.C., United States
| | - Matthew Whitehead
- Division of Radiology, Children's National Hospital, Washington D.C., United States
| | | | - Ljubica Caldovic
- Childrens' Research Institute, Children's National Hospital, Washington D.C., United States
| | - Andrea Gropman
- Division of Neurogenetics and Neurodevelopmental Pediatrics, Children's National Hospital, Washington D.C., United States.
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Iqbal K, Kummamuru H, Dasari N, Koritala T, Jain NK, Deepika K, Adhikari R. A Case of Valproic-Acid Induced Hyperammonemic Encephalopathy. Cureus 2021; 13:e20380. [PMID: 35036212 PMCID: PMC8753585 DOI: 10.7759/cureus.20380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2021] [Indexed: 11/23/2022] Open
Abstract
Valproic acid (VPA), an antiepileptic medication, is known to cause hyperammonemia, which may be asymptomatic or can present with encephalopathy. VPA-induced hyperammonemic encephalopathy (VHE) is a serious but reversible condition, which requires high clinical suspicion for diagnosis. It may occur acutely or after chronic use of VPA. We present the case of a 44-year-old male who was on long-term VPA therapy for a seizure disorder. He presented to the emergency department with the complaint of two episodes of seizures two days before admission. On arrival, the patient was confused and tearful and was unable to recollect the events leading to the seizure. The initial complete metabolic panel, liver function tests, urinalysis, and serum VPA levels were observed to be normal. However, there was a marked elevation in ammonia levels. VPA was suspected to be the inciting agent of hyperammonemic encephalopathy, and, therefore, it was discontinued. The patient was started on oral lactulose and prescribed a different anti-seizure medication (i.e., lamotrigine). His ammonia levels decreased gradually, and his condition improved. Thus, it was concluded that the patient had developed VHE. At the time of discharge, he was stable and had no confusion or seizures. This case report evaluates his presentation and discusses the possible pathogenesis of VHE.
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4
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Valproic acid-induced encephalopathy: A review of clinical features, risk factors, diagnosis, and treatment. Epilepsy Behav 2021; 120:107967. [PMID: 34004407 DOI: 10.1016/j.yebeh.2021.107967] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/02/2021] [Accepted: 04/02/2021] [Indexed: 11/23/2022]
Abstract
Valproic acid (VPA), or sodium valproate, is a commonly used medication for seizure disorders, migraines, and mental illness. Although VPA is relatively safe, it still has several adverse effects; among these, VPA-induced encephalopathy is the most serious. Valproic acid-induced encephalopathy mainly manifests as acute or subacute encephalopathy and has been associated with hyperammonemia, L-carnitine deficiency, and urea cycle enzyme dysfunction. Delayed identification of VPA-induced encephalopathy could be potentially fatal. Here, we perform an extensive review of relevant literature pertaining to VPA-induced encephalopathy, including its epidemiology, clinical features, possible pathophysiology, risk factors, diagnosis, and treatment.
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Dinçer M, Akgün A, Bodur Ş, Gül H, Taş Torun Y, Bolu A, Çelik C, Çetinkaya M, Kara H, Cöngöloğlu MA. Hyperammonemic encephalopathy without hepatic dysfunction due to treatment with valproate: four cases and a mini review. PSYCHIAT CLIN PSYCH 2018. [DOI: 10.1080/24750573.2018.1448133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- Mustafa Dinçer
- Child and Adolescent Psychiatry Department, Gülhane Research and Training Hospital, Ankara, Turkey
| | - Abdullah Akgün
- Psychiatry Department, Gülhane Research and Training Hospital, Ankara, Turkey
| | - Şahin Bodur
- Child and Adolescent Psychiatry Department, Gülhane Research and Training Hospital, Ankara, Turkey
| | - Hesna Gül
- Child and Adolescent Psychiatry Department, Gülhane Research and Training Hospital, Ankara, Turkey
| | - Yasemin Taş Torun
- Child and Adolescent Psychiatry Department, Gülhane Research and Training Hospital, Ankara, Turkey
| | - Abdullah Bolu
- Psychiatry Department, Gülhane Research and Training Hospital, Ankara, Turkey
| | - Cemil Çelik
- Psychiatry Department, Gülhane Research and Training Hospital, Ankara, Turkey
| | - Miray Çetinkaya
- Child and Adolescent Psychiatry Department, Sami Ulus Child Hospital, Ankara, Turkey
| | - Halil Kara
- Child and Adolescent Psychiatry Department, Aksaray State Hospital, Aksaray, Turkey
| | - M. Ayhan Cöngöloğlu
- Child and Adolescent Psychiatry Department, Gülhane Research and Training Hospital, Ankara, Turkey
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6
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Ott CA, Campbell N, Dworek EA. Valproic Acid—Induced Hyperammonemia in a Patient With Schizoaffective Disorder. J Pharm Pract 2016. [DOI: 10.1177/0897190007303054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Valproic acid is used in psychiatry as a mood stabilizer and can be very effective in reducing symptoms of agitation. Valproic acid may cause hyperammonemia through carnitine deficiency created by its inhibition of mitochondrial enzymes in the urea cycle. Clinical presentation of hyperammonemia usually involves lethargy and somnolence, which may also be noted with therapeutic serum concentration during valproic acid therapy. The diagnosis of hyperammonemia is often overlooked due to a clinical presentation that may include normal liver enzyme tests and serum valproate levels that are within the therapeutic range. Treatment modalities may include discontinuation of valproic acid therapy, lactulose, naloxone, and hemodialysis. Carnitine supplementation, for both prevention and acute treatment of hyperammonemia, has been anecdotally reported and may be considered. This article illustrates a case of an adult male with schizoaffective disorder who was treated with valproic acid and subsequently developed hyperammonemia, despite therapeutic valproic acid serum levels and normal liver enzyme tests. Possible causes of hyperammonemia and current treatment options will be described, as well as suggestions for monitoring for this adverse event in the clinical setting.
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Affiliation(s)
- Carol A. Ott
- Purdue University School of Pharmacy and Pharmaceutical Sciences, West Lafayette, IN,
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7
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Chan E, McQueen F. Valproate-induced hyperammonaemia superimposed upon severe neuropsychiatric lupus: a case report and review of the literature. Clin Rheumatol 2012; 32:403-7. [PMID: 23271612 DOI: 10.1007/s10067-012-2150-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 12/10/2012] [Indexed: 12/01/2022]
Abstract
This paper presents a case of systemic lupus erythematosus (SLE) with neuropsychiatric features, where the outcome was influenced by the development of hyperammonaemia, probably induced by sodium valproate. A case of severe SLE occurring in a 20-year-old Maori girl is described. Her disease had been characterised by neuropsychiatric features for several years, culminating in persistent seizure activity at the time of her final presentation. Her management with anticonvulsants was complicated by the development of intractable hyperammonaemia which contributed to irreversible clinical deterioration. We have reviewed the English literature for reports of valproate-related hyperammonaemia which has often been described in the setting of seizure and mood disorders. This is the first case where it has been reported, superimposed upon severe neuropsychiatric SLE (NP-SLE). The mechanism by which valproate induces hyperammonaemia remains incompletely understood but is likely to relate to the urea cycle. Under normal metabolic conditions, acyl-CoA is transported into the mitochondria via a carnitine transport system. It is then converted to acetyl-CoA via β-oxidation and eventually to N-acetyl glutamate. This pathway can be interrupted by the introduction of sodium valproate, leading to a reduction of free coenzyme A, acetyl-CoA and carnitine, and resulting in the decreased availability of cofactors necessary for the function of the urea cycle. As this is the primary means of ammonia metabolism, serious elevation in serum ammonia levels may occur in patients on this anticonvulsant medication. In this patient with active NP-SLE, the combined autoimmune and metabolic brain insult contributed to a fatal outcome.
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Affiliation(s)
- Estee Chan
- Department of Rheumatology, Greenlane Clinical Centre, Auckland District Health Board, Private Bag 92024, Auckland Mail Centre, Auckland 1142, New Zealand.
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Chopra A, Kolla BP, Mansukhani MP, Netzel P, Frye MA. Valproate-induced hyperammonemic encephalopathy: an update on risk factors, clinical correlates and management. Gen Hosp Psychiatry 2012; 34:290-8. [PMID: 22305367 DOI: 10.1016/j.genhosppsych.2011.12.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 12/14/2011] [Accepted: 12/16/2011] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Valproate (VPA)-induced hyperammonemic encephalopathy (VHE) is a serious drug-related adverse effect characterized by lethargy, vomiting, cognitive slowing, focal neurological deficits and decreased levels of consciousness ranging from drowsiness to coma. METHODS We present a case series (n=5) and also review previous cases of VHE (n=30) in psychiatric patients to provide an update on risk factors, clinical correlates and management of VHE. RESULTS To our knowledge, there are 30 (16 female, 14 male) previously reported VHE cases in psychiatric patients. Risk factors for VHE include VPA-drug interactions, mental retardation, carnitine deficiency and presence of urea cycle disorders. Length of VPA treatment, VPA dosage, serum VPA levels and serum ammonia levels do not appear to correlate with onset or severity of VHE.VPA discontinuation is the primary treatment of VHE, although, l-carnitine, lactulose and neomycin have been used adjunctively in some patients. CONCLUSION Clinicians should consider VHE in patients taking VPA who present with lethargy, gastrointestinal symptoms, confusion and decreased levels of drowsiness. VPA discontinuation is currently the mainstay of treatment for VHE, although more research is warranted to delineate the underlying risk factors for VHE and consolidate treatment modalities for this potentially life-threatening drug adverse effect.
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Affiliation(s)
- Amit Chopra
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN 55905, USA
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9
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Bezinover D, Postula M, Donahue K, Bentzen B, McInerney J, Janicki PK. Perioperative Exacerbation of Valproic Acid–Associated Hyperammonemia. Anesth Analg 2011; 113:858-61. [DOI: 10.1213/ane.0b013e318228a001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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10
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Young L, Coffey BJ. Bipolar disorder and valproate-induced hyperammonemic encephalopathy in an adolescent with diabetes. J Child Adolesc Psychopharmacol 2010; 20:449-52. [PMID: 20973717 DOI: 10.1089/cap.2010.2052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Lawrence Young
- New York University Child Study Center, New York, NY 10016, USA
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11
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Brusilow SW, Koehler RC, Traystman RJ, Cooper AJL. Astrocyte glutamine synthetase: importance in hyperammonemic syndromes and potential target for therapy. Neurotherapeutics 2010; 7:452-70. [PMID: 20880508 PMCID: PMC2975543 DOI: 10.1016/j.nurt.2010.05.015] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 05/17/2010] [Accepted: 05/19/2010] [Indexed: 12/21/2022] Open
Abstract
Many theories have been advanced to explain the encephalopathy associated with chronic liver disease and with the less common acute form. A major factor contributing to hepatic encephalopathy is hyperammonemia resulting from portacaval shunting and/or liver damage. However, an increasing number of causes of hyperammonemic encephalopathy have been discovered that present with the same clinical and laboratory features found in acute liver failure, but without liver failure. Here, we critically review the physiology, pathology, and biochemistry of ammonia (i.e., NH3 plus NH4+) and show how these elements interact to constitute a syndrome that clinicians refer to as hyperammonemic encephalopathy (i.e., acute liver failure, fulminant hepatic failure, chronic liver disease). Included will be a brief history of the status of ammonia and the centrality of the astrocyte in brain nitrogen metabolism. Ammonia is normally detoxified in the liver and extrahepatic tissues by conversion to urea and glutamine, respectively. In the brain, glutamine synthesis is largely confined to astrocytes, and it is generally accepted that in hyperammonemia excess glutamine compromises astrocyte morphology and function. Mechanisms postulated to account for this toxicity will be examined with emphasis on the osmotic effects of excess glutamine (the osmotic gliopathy theory). Because hyperammonemia causes osmotic stress and encephalopathy in patients with normal or abnormal liver function alike, the term "hyperammonemic encephalopathy" can be broadly applied to encephalopathy resulting from liver disease and from various other diseases that produce hyperammonemia. Finally, the possibility that a brain glutamine synthetase inhibitor may be of therapeutic benefit, especially in the acute form of liver disease, is discussed.
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Affiliation(s)
- Saul W. Brusilow
- grid.21107.350000000121719311Department of Pediatrics, The Johns Hopkins University School of Medicine, 21287 Baltimore, MD
| | - Raymond C. Koehler
- grid.21107.350000000121719311Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, 21287 Baltimore, MD
| | - Richard J. Traystman
- Office of the Vice Chancellor for Research, Department of Pharmacology, University of Colorado Denver, 80045 Aurora, CO
| | - Arthur J. L. Cooper
- grid.260917.b000000010728151XDepartment of Biochemistry and Molecular Biology, New York Medical College, 10595 Valhalla, NY
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Lheureux PE, Hantson P. Carnitine in the treatment of valproic acid-induced toxicity. Clin Toxicol (Phila) 2009; 47:101-11. [DOI: 10.1080/15563650902752376] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Valproate-induced hyperammonaemic encephalopathy: review of 14 cases in the psychiatric setting. Int Clin Psychopharmacol 2007; 22:330-7. [PMID: 17917551 DOI: 10.1097/yic.0b013e3281c61b28] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To review signs and symptoms of valproate-induced hyperammonaemic encephalopathy without hepatotoxicity in the psychiatric setting, explore its mechanisms, and give recommendations for prevention and treatment. METHODS Medline search with keywords valproate, ammonia, hyperammonaemia, encephalopathy, and then cross-references to articles obtained through this search. Only cases with indication of valproate for psychiatric condition were included. RESULTS Fourteen cases published in the psychiatric setting are reviewed. Valproate-induced hyperammonaemic encephalopathy is a rare adverse event, occurring almost equally in men and women, with a large age range, and reported in two patients with mental retardation. Symptoms appeared either a few days after initiation of valproate therapy, or after several months or years. The main symptoms were fluctuations in consciousness and disorientation. Clinical severity was not related to blood ammonia levels. All patients recovered after valproate-induced hyperammonaemic encephalopathy diagnosis and treatment, usually involving discontinuation of valproate. CONCLUSIONS Valproate-induced hyperammonaemic encephalopathy is rare and usually reversible in patients without urea cycle disorders when valproate is discontinued. Therapy with carnitine is recommended. Special caution should be used in patients with mental retardation. Psychiatrists should suspect valproate-induced hyperammonaemic encephalopathy when consciousness deteriorates.
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14
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Gerstner T, Buesing D, Longin E, Bendl C, Wenzel D, Scheid B, Goetze G, Macke A, Lippert G, Klostermann W, Mayer G, Augspach-Hofmann R, Fitzek S, Haensch CA, Reuland M, Koenig SA. Valproic acid induced encephalopathy – 19 new cases in Germany from 1994 to 2003 – A side effect associated to VPA-therapy not only in young children. Seizure 2006; 15:443-8. [PMID: 16787750 DOI: 10.1016/j.seizure.2006.05.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 05/10/2006] [Accepted: 05/23/2006] [Indexed: 01/26/2023] Open
Abstract
Valproic acid (VPA) is a broad-spectrum antiepileptic drug and is usually well-tolerated. Rare serious complications may occur in some patients, including haemorrhagic pancreatitis, bone marrow suppression, VPA-induced hepatotoxicity and VPA-induced encephalopathy. The typical signs of VPA-induced encephalopathy are impaired consciousness, sometimes marked EEG background slowing, increased seizure frequency, with or without hyperammonemia. There is still no proof of causative effect of VPA in patients with encephalopathy, but only of an association with an assumed causal relation. We report 19 patients with VPA-associated encephalopathy in Germany from the years 1994 to 2003, none of whom had been published previously.
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Affiliation(s)
- Thorsten Gerstner
- University Children's Hospital Mannheim, Neuropediatric Unit, Theodor-Kutzer-Ufer 1-3, 69167 Mannheim, Germany
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Summar ML, Barr F, Dawling S, Smith W, Lee B, Singh RH, Rhead WJ, Sniderman King L, Christman BW. Unmasked adult-onset urea cycle disorders in the critical care setting. Crit Care Clin 2006; 21:S1-8. [PMID: 16227111 DOI: 10.1016/j.ccc.2005.05.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Most often, urea cycle disorders have been described as acute onset hyperammonemia in the newborn period; however, there is a growing awareness that urea cycle disorders can present at almost any age, frequently in the critical care setting. This article presents three cases of adult-onset hyperammonemia caused by inherited defects in nitrogen processing in the urea cycle, and reviews the diagnosis, management, and pathophysiology of adult-onset urea cycle disorders. Individuals who have milder molecular urea cycle defects can lead a relatively normal life until a severe environmental stress triggers a hyperammonemic crisis. Comorbid conditions such as physical trauma often delay the diagnosis of the urea cycle defect. Prompt recognition and treatment are essential in determining the outcome of these patients.
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Affiliation(s)
- Marshall L Summar
- Center for Human Genetic Research, Division of Medical Genetics, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232-0165, USA.
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Turcato MDF, Fernandes RMF, Wichert-Ana L, Funayama CAR. Hiperamonemia secundária ao uso terapêutico de ácido valpróico: relato de caso. ARQUIVOS DE NEURO-PSIQUIATRIA 2005; 63:364-6. [PMID: 16100994 DOI: 10.1590/s0004-282x2005000200034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
O ácido valpróico tem sido amplamente utilizado no tratamento da epilepsia, sendo usualmente bem tolerado, não obstante alguns efeitos colaterais que lhe são atribuídos. Um efeito ainda pouco conhecido é a hiperamonemia, independente da hepatotoxicidade da droga. A hiperamonemia se estabelece no início ou no decurso do tratamento, sendo caracterizada por vômitos, alteração progressiva da consciência, sinais neurológicos focais e aumento na freqüência das crises epilépticas. Descrevemos o caso de menino de seis anos de idade que desenvolveu hiperamonemia pelo uso terapêutico de ácido valpróico. Os exames descartaram aminoacidopatias, acidemias orgânicas e distúrbios do ciclo da uréia, sendo a hipótese de efeito secundário reiterada pela normalização da concentração sangüínea de amônia, após a retirada do medicamento. Os mecanismos da hiperamonemia são discutidos, concluindo-se que o monitoramento da amônia é importante nos pacientes que utilizam o ácido valpróico.
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Affiliation(s)
- Marlene de Fátima Turcato
- Departamento de Neurologia, Psiquiatria e Psicologia Médica, Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
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17
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Wargo KA, Wavra MG. A Case of Hyperammonemic Encephalopathy Secondary to a Combination of Valproic Acid and Topiramate. Hosp Pharm 2005. [DOI: 10.1177/001857870504000308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Purpose To report a case of hyperammonemic encephalopathy induced by a combination of valproic acid and topiramate. Case Summary A 30-year-old male was admitted to our institution after experiencing headaches, decreasing mental capacity and increasing somnolence over the previous 3 days. Past medical history was significant for generalized tonic-clonic seizure disorder and mild mental retardation for which he had been regularly taking valproic acid, topiramate, and lorazepam. The patient was seizure free for the past 9 months prior to his seizure 2 weeks prior to admission. Upon presentation, an electroencephalogram revealed excessive slowing in the left more than right, with a differential consistent with a metabolic encephalopathy, head injury, or postictal state. Laboratory workup revealed a valproic acid level that was slightly elevated, but still within normal limits, at 92.5 mcg/mL (normal = 50 to 100 mcg/mL). Furthermore, the patient's ammonia level was found to be elevated at 72 mcg/dL (normal = 14.7 to 55.3 mcg/dL). On hospital day 3, after discovering these findings, valproic acid was discontinued and lactulose 20 g three times daily was started. Five days after admission, the patient's mental status changes were resolved, and he was discharged with an ammonia level of 57 mcg/dL. Conclusion Hyperammonemic encephalopathy is rare, but a serious and sometimes fatal disorder can occur in patients receiving valproic acid therapy. The incidence of hyperammonemia may be increased in patients receiving concomitant valproic acid and topiramate therapy. In patients on valproic acid and topiramate who present with altered mental status, an ammonia level in addition to a serum valproate level should be ascertained to rule out this potentially serious adverse drug reaction.
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Affiliation(s)
- Kurt A. Wargo
- Internal Medicine, Auburn University Harrison School of Pharmacy
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18
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Ricard C, Martin K, Tournier M, Bégaud B, Verdoux H. Troubles cognitifs, syndrome extrapyramidal et hyperammoniémie sous traitement thymorégulateur par divalproate de sodium : à propos d’un cas. Encephale 2005; 31:98-101. [PMID: 15971646 DOI: 10.1016/s0013-7006(05)82378-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Several cases of Parkinsonian syndrome, cognitive impairment or hyperammonemia induced by sodium valproate have been described in the literature. We report the first case presenting an association of the three adverse effects occurring with divalproate sodium prescribed for bipolar disorder: a 58-year-old man with a history of bipolar type I disorder presented with Parkinsonian syndrome and cognitive impairment of insidious onset. This patient had been treated for several years with lithium carbonate, with a successful effect on mood swings, but with distressing adverse effects such as hand tremor and diarrhoea. Lithium therapy was progressively withdrawn while sodium divalproate was initiated. Associated medications, unchanged for several years, were amisulpride (daily dose: 100 mg), liothyronine, ciprofibrate and benfluorex. The patient was treated with sodium divalproate for seven months (daily dose: 1,000 mg), and with trihexyphenidyle for one month for extrapyramidal symptoms. At hospital admission, he presented with temporal disorientation, slowed thinking, severe anterograde memory deficits, and Parkinsonian syndrome. The minimal mental state (MMS) score was 16 (maximum: 30). The patient was anxious but did no present with mood symptoms. He also developed hyperammonemia (124 micromol/liter, normal range: 15 to 60 micromol/liter) without signs or biochemical evidence of hepatic failure. Valproate concentrations were within the therapeutic ranges (79 mg/l, normal range: 50 to 100 mg/l). The CT-scan showed cerebral and cerebellar atrophy with enlarged ventricles. The electroencephalogram showed generalized slowing waves. All the symptoms resolved within one month after the withdrawal of divalproate: the extrapyramidal hypertonia resolved, the MMS score was 29. The CT-scan and the electroencephalogram returned to normal. The divalproate was replaced by lithium. After a one-year follow-up, the cognitive and neurological symptomatology did not reappear at the exception of the pre-existing hand tremor. The pathophysiology of valproate induced hyperammonemic encephalopathy remains unclear. A possible mechanism is neuronal toxicity induced by increased intracellular concentrations of glutamate and ammonium in astrocytes. Indeed, these abnormal intracellular concentrations increase the intracellular osmolarity and thus induce rise in intracranial pressure and cerebral oedema. Reversible dementia could be due to a direct toxic effect of valproate on the central nervous system or to an indirect effect mediated through valproate-induced hyperammonemia. It has been suggested that the occurrence of extrapyramidal syndrome could be explained by a disturbance in the GABAergic pathways inducing reversible dopamine inhibition. A drug adverse reaction should always be considered when a patient treated with valproate presents with extrapyramidal symptoms and cognitive disorders even when valproate concentrations are within standard therapeutic ranges.
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Affiliation(s)
- C Ricard
- EA3676 Médicaments, Produits et Systèmes de Santé, IFR99 de Santé Publique, Université Victor Segalen Bordeaux 2, Bordeaux, France
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Kimmel RJ, Irwin SA, Meyer JM. Valproic acid-associated hyperammonemic encephalopathy: a case report from the psychiatric setting. Int Clin Psychopharmacol 2005; 20:57-8. [PMID: 15602119 DOI: 10.1097/00004850-200501000-00012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Valproic acid-associated hyperammonemic encephalopathy (VHE) has been described in the neurology and emergency medicine literature, but the case reports identified therein are rarely derived from the psychiatric use of this medication. Valproic acid is widely used as a mood stabilizer in bipolar affective disorder and schizoaffective disorder. Patients with normal blood levels, liver function and metabolic tests may present with markedly elevated ammonia and a variety of neurological symptoms. We report the case of a patient on long-term valproic acid therapy, with stable dosing, who presented with an elevated ammonia level, new-onset tremor, confusion, and loss of consciousness. This case illustrates the need to check ammonia levels in psychiatric patients who are taking valproic acid and who present with new neurological symptoms.
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Affiliation(s)
- Ryan J Kimmel
- Department of Psychiatry, University of California San Diego, La Jolla, California 92093-0603R, USA.
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