Valproate-associated hyperammonemic encephalopathy

L-carnitine for valproic acid-induced toxicity

AIMS

Review the effectiveness and dosing of L-carnitine for valproic-acid induced toxicity.

METHODS

A literature review of the pharmacokinetics and clinical use of L-carnitine was performed.

RESULTS

Valproic acid is a fatty acid used for numerous therapeutic indications ranging from epilepsy to bipolar disorder. The metabolism of valproic acid produces both therapeutic and toxic metabolites. Whilst it has a good safety profile, adverse effects of valproic acid in chronic use include hepatotoxicity ranging from transient elevation of liver enzymes to fulminant liver failure and hyperammonaemia with resultant encephalopathy. L-carnitine is an essential cofactor for mitochondrial fatty acid metabolism, which is an important source of energy in cardiac and skeletal muscle. Physiological concentrations of L-carnitine are maintained in man by exogenous dietary intake and endogenous synthesis. Following exogenous oral administration of L-carnitine, the bioavailability ranges from 14% to 18%. After bolus intravenous administration of L-carnitine in doses ranging from 20 to 100 mg/kg, the volume of distribution is 0.2-0.3 L/kg, and the fraction excreted unchanged in urine is 0.73-0.95, suggesting that renal clearance of L-carnitine is dose dependent due to saturable renal reabsorption at supraphysiological concentrations.

CONCLUSIONS

There is evidence supporting the use of L-carnitine in treating hyperammonaemia and hepatotoxicity following chronic therapeutic use and after acute overdose of valproic acid, but the optimal dose and route of administration is unknown. Based on the pharmacokinetics of L-carnitine, we advocate the administration of L-carnitine for valproic-acid induced hyperammonaemia or hepatotoxicity as an intravenous loading dose of 5 mg/kg followed by a continuous intravenous infusion instead of the oral or intravenous boluses that are currently advocated.

Factors Influencing Plasma Concentrations of Valproic Acid in Pediatric Patients With Epilepsy and the Clinical Significance of CYP2C9 Genotypes in Personalized Valproic Acid Therapy

BACKGROUND

The aim of this study was to investigate the factors affecting plasma valproic acid (VPA) concentration in pediatric patients with epilepsy and the clinical significance of CYP2C9 gene polymorphisms in personalized dosing using therapeutic drug monitoring and pharmacogenetic testing.

METHODS

The medical records of children with epilepsy who underwent therapeutic drug monitoring at our institution between July 2022 and July 2023 and met the inclusion criteria were reviewed. Statistical analysis was performed to determine whether age, sex, blood ammonia, liver function, kidney function, and other characteristics affected the concentration-to-dose ratio of VPA (CDRV) in these patients. To investigate the effect of CYP2C9 polymorphisms on CDRV, DNA samples were collected from patients and the CYP2C9 genotypes were identified using real-time quantitative PCR.

RESULTS

The mean age of 208 pediatric patients with epilepsy was 5.50 ± 3.50 years. Among these patients, 182 had the CYP2C9 *1/*1 genotype, with a mean CDRV (mcg.kg/mL.mg) of 2.64 ± 1.46, 24 had the CYP2C9 *1/*3 genotype, with a mean CDRV of 3.28 ± 1.74, and 2 had the CYP2C9 *3/*3 genotype, with a mean CDRV of 6.46 ± 3.33. There were statistical differences among these 3 genotypes ( P < 0.05). The CDRV in these patients were significantly influenced by age, aspartate aminotransferase, total bilirubin, direct bilirubin, globulin, albumin/globulin ratio, prealbumin, creatinine, and CYP2C9 polymorphisms. In addition, multivariate linear regression analysis identified total bilirubin, direct bilirubin, and CYP2C9 polymorphisms as independent risk factors for high CDRV.

CONCLUSIONS

Liver problems and mutations in the CYP2C9 gene increase VPA levels. This underscores the importance of considering these factors when prescribing VPA to children with epilepsy, thereby enhancing the safety and efficacy of the therapy.

The Effect of L-Carnitine on Critical Illnesses Such as Traumatic Brain Injury (TBI), Acute Kidney Injury (AKI), and Hyperammonemia (HA)

L-carnitine (LC) through diet is highly beneficial for critical patients. Studies have found that acetyl-L-carnitine (ALC) can reduce cerebral edema and neurological complications in TBI patients. It significantly improves their neurobehavioral and neurocognitive functions. ALC has also been shown to have a neuroprotective effect in cases of global and focal cerebral ischemia. Moreover, it is an effective agent in reducing nephrotoxicity by suppressing downstream mitochondrial fragmentation. LC can reduce the severity of renal ischemia-reperfusion injury, renal cast formation, tubular necrosis, iron accumulation in the tubular epithelium, CK activity, urea levels, Cr levels, and MDA levels and restore the function of enzymes such as SOD, catalase, and GPx. LC can also be administered to patients with hyperammonemia (HA), as it can suppress ammonia levels. It is important to note, however, that LC levels are dysregulated in various conditions such as aging, cirrhosis, cardiomyopathy, malnutrition, sepsis, endocrine disorders, diabetes, trauma, starvation, obesity, and medication interactions. There is limited research on the effects of LC supplementation in critical illnesses such as TBI, AKI, and HA. This scarcity of studies highlights the need for further research in this area.

Exploring the Therapeutic Potential of Peritoneal Dialysis (PD) in the Treatment of Neurological Disorders

Peritoneal dialysis (PD) is a well-established renal replacement therapy commonly employed in clinical practice. While its primary application is in the treatment of kidney disease, its potential in addressing other systemic disorders, including neurological diseases, has garnered increasing interest. This study provides a comprehensive overview of the related technologies, unique advantages, and clinical applications of PD in the context of neurological disorders. By exploring the mechanism underlying PD, its application in neurological diseases, and associated complications, we addressed the feasibility and benefits of PD as an adjunct therapy for various neurological conditions. Our study aims to highlight its role in detoxification and symptom management, as well as its advantages over other universally accepted methods of renal replacement therapy. Our goal is to bring to the spotlight the therapeutic potential of PD in neurological diseases, such as stroke, stimulate further research, and broaden the scope of its application in the clinical setting.

Neuroprotective Properties of Antiepileptics: What are the Implications for Psychiatric Disorders?

Since the discovery of the first antiepileptic compound, increasing attention has been paid to antiepileptic drugs (AEDs), and recently, with the understanding of the molecular mechanism underlying cells death, a new interest has revolved around a potential neuroprotective effect of AEDs. While many neurobiological studies in this field have focused on the protection of neurons, growing data are reporting how exposure to AEDs can also affect glial cells and the plastic response underlying recovery; however, demonstrating the neuroprotective abilities of AEDs remains a changeling task. The present work aims to summarize and review the literature available on the neuroprotective properties of the most commonly used AEDs. Results highlighted how further studies should investigate the link between AEDs and neuroprotective properties; while many studies are available on valproate, results for other AEDs are very limited and the majority of the research has been carried out on animal models. Moreover, a better understanding of the biological basis underlying neuro-regenerative defects may pave the way for the investigation of further therapeutic targets and eventually lead to an improvement in the actual treatment strategies.

Valproate-Induced Hyperammonemic Encephalopathy Causing New-Onset Seizures

Valproate-induced hyperammonemic encephalopathy (VHE) is a rare and severe side effect that can occur with valproic acid (VPA) therapy, despite therapeutic doses and normal serum levels of valproate. The typical signs of this condition include a sudden onset of impaired consciousness, focal neurologic symptoms, and an increase in seizure frequency. The exact cause of VHE is unknown, but it is believed to be related to the accumulation of toxic VPA metabolites and increased levels of ammonia that can cause swelling of the astrocytes and cerebral edema. We present a case of a 19-year-old male patient with a history of bipolar disorder on valproic acid 250 mg daily, admitted to the hospital after a new-onset seizure. He was found to have elevated levels of ammonia in his blood, despite having therapeutic levels of valproate and no liver dysfunction. His symptoms improved with discontinuation of the medication and his ammonia levels decreased. We discuss possible mechanisms and risk factors leading to encephalopathy while on valproate therapy. VHE should be considered a possibility when patients treated with valproate show signs of impaired consciousness.

Challenges in the Clinical Diagnosis of Lithium Toxicity: A Case Report

Lithium, a medication commonly used to treat bipolar disorders, has a narrow therapeutic index, putting patients at risk of lithium toxicity. Such toxicity could entail neurological-related complications and could be precipitated by several factors. In this paper, the authors discuss a case of a middle-aged woman taking lithium for bipolar disorder who presented to the emergency department with altered mental status, tremors, generalized weakness, and dysarthria. Multiple differential diagnoses were considered during her hospitalization, which included an admission to the intensive care unit. This case highlights the variability of lithium toxicity presentations and its management challenges. Further research is needed to understand such manifestations, potential precipitating factors, differential diagnoses, and effective detection and management.

Valproic Acid-Associated Hyperammonemia: A Systematic Review

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.

Quantitative systems pharmacology Model to characterize valproic acid-induced hyperammonemia and the effect of L-carnitine supplementation

Valproic acid (VPA) is a short-chain fatty acid widely prescribed in the treatment of seizure disorders and epilepsy syndromes, although its therapeutic value may be undermined by its toxicity. VPA serious adverse effects are reported to have a significant and dose-dependent incidence, many associated with VPA-induced hyperammonemia. This effect has been linked with reduced levels of carnitine; an endogenous compound involved in fatty acid's mitochondrial β-oxidation by facilitation of its entrance via the carnitine shuttle. High exposure to VPA can lead to carnitine depletion causing a misbalance between the intra-mitochondrial β-oxidation and the microsomal ω-oxidation, a pathway that produces toxic metabolites such as 4-en-VPA which inhibits ammonia elimination. Moreover, a reduction in carnitine levels might be also related to VPA-induced obesity and lipids disorder. In turn, L-carnitine supplementation (CS) has been recommended and empirically used to reduce VPA's hepatotoxicity. The aim of this work was to develop a Quantitative Systems Pharmacology (QSP) model to characterize VPA-induced hyperammonemia and evaluate the benefits of CS in preventing hyperammonemia under both chronic treatment and after VPA overdosing. The QSP model included a VPA population pharmacokinetics model that allowed the prediction of total and unbound concentrations after single and multiple oral doses considering its saturable binding to plasma proteins. Predictions of time courses for 2-en-VPA, 4-en-DPA, VPA-glucuronide, carnitine, ammonia and urea levels, and for the relative change in fatty acids, Acetyl-CoA, and glutamate reflected the VPA induced changes and the efficacy of the treatment with L-carnitine. The QSP model was implemented to give a rational basis for the L-carnitine dose selection to optimize CS depending on VPA dosage regime and to assess the currently recommended L-carnitine rescue therapy after VPA overdosing. Results show that a L-carnitine dose equal to the double of the VPA dose using the same interdose interval would maintain the ammonia levels at baseline. The QSP model may be expanded in the future to describe other adverse events linked to VPA-induced changes in endogenous compounds.

Hyperammonemic Encephalopathy in Multiple Myeloma: A Case Report

Multiple myeloma (MM) typically presents as lytic bony lesions, hypercalcemia, anemia, and renal failure. Only a few cases of hyperammonemic encephalopathy (HE) attributed to multiple myeloma have been reported. We report a case of a 68-year-old Hispanic female diagnosed with multiple myeloma and presented with altered mental status and elevated ammonia levels found to have HE. The pathology behind HE is associated with higher ammonia levels produced by myeloma cell lines in the absence of liver disease. Due to the wide range of differentials for altered mental status (AMS), HE often gets missed and causes delayed treatment and the associated higher mortality. The primary treatment is chemotherapy. Lactulose and rifaximin must be initiated; however, it is ineffective if solely used. In our case, chemotherapy was not considered a treatment option in light of the patient's pancytopenia and infection. Our case is unique, as despite adequately treating other commonly suspected causes of AMS such as infection, there was no expected improvement in the patient's clinical status noticed, eventually leading to intubation due to worsening AMS. Given the patient's history of multiple myeloma, non-compliance with chemotherapy before presentation, and elevated ammonia levels raised suspicion for HE. Clinicians are encouraged to acquaint themselves with HE as a differential for patients presenting with MM flare and AMS, specifically when other potential causes of AMS are ruled out and addressed.

Non-hyperammonaemia valproate-induced encephalopathy: A case report

WHAT IS KNOWN AND OBJECTIVE

Valproate sodium is an effective antiepileptic drug (AED). Serious adverse effects of valproate sodium are uncommon. This case report illustrates the existence of non-hyperammonaemia valproate-induced encephalopathy.

CASE DESCRIPTION

A 47-year-old woman with epilepsy who developed valproate-induced encephalopathy without hyperammonaemia after valproate sodium treatment, and the symptoms completely subsided after withdrawal of valproate sodium.

WHAT IS NEW AND CONCLUSION

Early diagnosis and identification of the mechanisms of non-hyperammonaemia valproate-induced encephalopathy are important. Immediate discontinuation of valproate sodium results in rapid resolution of symptoms in these patients.

Valproic acid-induced encephalopathy: A review of clinical features, risk factors, diagnosis, and treatment

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.

Prognostic Role of Ammonia in Critical Care Patients Without Known Hepatic Disease

Background and Aims: Hyperammonemia usually develops because of hepatic disease, but it may occur in patients with non-hepatic hyperammonemia (NHH). But, studies on the prognosis and possible risk factors of this disorder are lacking. The aim of this study was to find possible prognostic and risk factors for NHH in critically ill patients.

Methods: Data were extracted from MIMIC III Database. Survival was analyzed by the Kaplan-Meier method. Univariate and multivariate analyses were performed to identify prognostic factors.

Results: Valproic acid, carbamazepine, corticosteroids, recent orthopedic surgery, epilepsy, disorders of urea cycle metabolism, and obesity were found to be risk factors for NHH. Patients in the hyperammonemia group had a higher 30 day mortality than those in the non-hyperammonemia group. After final regression analysis, ammonia was found to be independent predictors of mortality.

Conclusion: Ammonia was an independent prognostic predictor of 30 day mortality for critical care patients without liver disease.

Alcohol Withdrawal Syndrome in Neurocritical Care Unit: Assessment and Treatment Challenges

Alcohol withdrawal syndrome (AWS) can range from mild jittery movements, nausea, sweating to more severe symptoms such as seizure and death. Severe AWS can worsen cognitive function, increase hospital length of stay, and in-hospital mortality and morbidity. Due to a lack of reliable history of present illness in many patients with neurological injury as well as similarities in clinical presentation of AWS and some commonly encountered neurological syndromes, the true incidence of AWS in neurocritical care patients remains unknown. This review discusses challenges in the assessment and treatment of AWS in patients with neurological injury, including the utility of different scoring systems such as the Clinical Institute Withdrawal Assessment and the Minnesota Detoxification Scale as well as the reliability of admission alcohol levels in predicting AWS. Treatment strategies such as symptom-based versus fixed dose benzodiazepine therapy and alternative agents such as baclofen, carbamazepine, dexmedetomidine, gabapentin, phenobarbital, ketamine, propofol, and valproic acid are also discussed. Finally, a treatment algorithm considering the neurocritical care patient is proposed to help guide therapy in this setting.

Non-cirrhotic hyperammonaemia: are we missing the diagnosis?

Hepatic encephalopathy secondary to hyperammonaemia is a known complication of chronic liver disease. In contrast, non-cirrhotic hyperammonaemia is a lesser-known entity that should be considered in a patient with acute encephalopathy as part of the diagnostic workup as prompt identification can help to avoid complications such as seizures and cerebral oedema. We present a case of a middle-aged woman who presented electively for a total pancreatectomy-duodenectomy with splenectomy, hepatico-jejunostomy, gastro-jejunostomy and developed encephalopathy on postoperative day 10 due to non-cirrhotic hyperammonaemia.

Valproate-induced hyperammonemic encephalopathy: a case report

Background

Hyperammonemic encephalopathy is a rare and serious adverse reaction to valproate. Although there is documentation of this reaction in previous reports, very little is still known about the exact mechanism of action. In addition, there are no established guidelines of the next steps needed when a patient does develop this reaction. Therefore, this case report highlights what is known as well as the areas of research still needed.

Case presentation

Our patient was a 57-year-old Caucasian woman with a medical history of bipolar I disorder, opioid use disorder, benzodiazepine use disorder, and Crohn’s disease who was admitted to our behavioral health unit for suicidal ideation. She had been experiencing multiple panic attacks for 2.5 weeks along with poor sleep, increased energy, excessive spending, and feelings of helplessness. The patient was diagnosed with bipolar I disorder, manic episode without psychotic features, and benzodiazepine use disorder. She was started on valproic acid, citalopram, propranolol, and quetiapine. By day 6 of her hospitalization, the patient had altered mental status, varying levels of consciousness, confusion, and ataxic gait. Her ammonia levels were found to be elevated. All of her medications were discontinued, and lactulose was initiated. She returned to her baseline mentation within 48 hours and was discharged with lithium and quetiapine. The treatment team concluded that this patient had valproate-induced hyperammonemic encephalopathy, a rare but reversible reaction to valproate.

Conclusion

Fortunately, rapid identification of this rare condition led to a favorable outcome in our patient. This case report illustrates the course of treatment in a patient who experienced this reaction and reviews current knowledge as well as areas of needed research in regard to valproate-induced hyperammonemic encephalopathy.

Levocarnitine for the Treatment of Valproic Acid-Induced Hyperammonemic Encephalopathy in Children: The Experience of a Large, Tertiary Care Pediatric Hospital and a Poison Center

BACKGROUND

Although rare, symptomatic hyperammonemia is sometimes associated with valproic acid (VPA), especially in children. L-carnitine (levocarnitine), sometimes classified as an essential amino acid, is vital to mitochondrial utilization of fatty acids and can be helpful in treating this condition. The data supporting this, however, are limited.

STUDY QUESTION

The aim of the study was to illustrate the role of L-carnitine in the treatment of patients with VPA-induced hyperammonemic encephalopathy (VPE) at 2 different institutions.

METHODS

Medical records of affected patients were reviewed; data collected included exposure history, clinical manifestations, physical examination, and laboratory values.

RESULTS

There were 13 cases of VPE; 12 were associated with therapeutic dosing and 1 with an overdose. The maximum ammonia concentration was 557 μmol/L, and blood concentrations of VPA ranged from 68 to 600 μg/mL (therapeutic range 50-100 μg/mL). In all cases, liver function tests were normal or only mildly increased. In this study, 12 patients received a daily dose of L-carnitine 100 mg/kg, and 1 received 200 mg/kg (intravenous infusion over 30 minutes) divided every 8 hours until clinical improvement. All patients made a full recovery. None developed adverse effects or reactions, and no cases of toxicity were reported.

CONCLUSION

Our series suggests that intravenous L-carnitine, at a dose of 100 mg·kg·d in 3 divided doses each over 30 minutes until clinical improvement occurs, is a safe and effective treatment in the management of VPE in children.

Severe hyperammonemia from intense skeletal muscle activity: A rare case report and literature review

RATIONALE

Adult hyperammonemia is most often the result of hepatic dysfunction. Hyperammonemia in the setting of normal hepatic function is a much less common phenomenon and has usually been associated with medications and certain disease states. Here, we present an unusual case of severe hyperammonemia caused physiologically by intense muscle activity in a patient lacking any evidence of liver disease.

PATIENT CONCERNS

A 36-year-old woman was brought to the emergency department for a suicide attempt after being found covered in Lysol and Clorox germicidal bleach. She was noted to be in a state of violent psychosis with extreme agitation and had to be sedated and intubated for airway protection.

DIAGNOSIS AND INTERVENTIONS

Initial labs revealed hyperammonemia, lactic acidosis, and anion gap metabolic acidosis. Aminotransferases, bilirubin, and creatine kinase (CK) were normal. Renal function, prothrombin time, activated partial thromboplastin time, and international normalized ratio were also unremarkable and remained so at 24 hours. Ethyl alcohol, acetaminophen, salicylate, and valproic acid were all undetectable in blood. She received 2 doses of lactulose overnight, with a subsequent bowel movement. Next day, her mentation, serum ammonia level, and lactic acid level were back to normal, and she was extubated. Aminotransferases and CK levels were elevated but improved with supportive care. A detailed history and relevant biochemical investigations were unremarkable for any other etiology of hyperammonemia including the common inborn errors of metabolism (IEM). The combination of clinical findings of extreme skeletal muscle activity along with hyperammonemia and lactic acidosis, and subsequently rhabdomyolysis in the setting of unremarkable history and otherwise normal hepatic function strongly suggest the myokinetic origin of hyperammonemia in the patient.

OUTCOME

The patient recovered well with supportive care and was discharged on day 5.

LESSONS

This unique case illustrates the important role of skeletal muscle in the human metabolism of ammonia. In our discussion, we also elucidate the underlying pathophysiology, with the objective of improving clinician understanding of various differential diagnoses.

Evaluation of sodium valproate loaded nanoparticles in acute and chronic pentylenetetrazole induced seizure models

BACKGROUND AND PURPOSE

Efficacy of sodium valproate in epilepsy is limited by its poor blood brain barrier penetration and side effects. Nanoparticles may offer a better drug delivery system to overcome these limitations. This study evaluated the efficacy of sodium valproate encapsulated in nanoparticles in pentylenetetrazole (PTZ) induced acute and kindling models of seizures in male Wistar rats.

METHODS

Poly lactic-co-glycolic acid (PLGA) based, polysorbate 80 stabilized sodium valproate loaded nanoparticles (nano sodium valproate) and rhodamine loaded nanoparticles (RLN) were formulated by double emulsion- solvent evaporation method and characterized for their size, shape, zeta potential and drug loading percentage. RLN was used to demonstrate blood brain barrier (BBB) permeability of nanoparticles. Serum drug levels were estimated using high performance liquid chromatography. The efficacy of standard sodium valproate (300 mg/kg) and nano sodium valproate (∼300, ∼150 and ∼75 mg/kg of sodium valproate) were evaluated in experimental animal models of seizures along with their effects on behavioral and oxidative stress parameters. Drugs were administered 60 min before PTZ in acute model. In the kindling model, drugs were administered every day while PTZ was administered on alternate days 60 min after drug administration. All the study drugs/compounds were administered intraperitoneally.

RESULTS

RLN were observed to be clustered in cortex which implied that the nanoparticles crossed BBB. Both standard sodium valproate and nano sodium valproate reached therapeutic serum level at 15 min and 1 h, but were undetectable in serum at 24 h. In acute PTZ (60 mg/kg) model, nano sodium valproate (∼300 mg/kg of sodium valproate) and standard sodium valproate showed protection against seizures till 6 h and 4 h, respectively. There were significant behavioral impairment and oxidative stress with standard sodium valproate in acute model as compared to nano sodium valproate at 6 h. In kindling model, induced with PTZ (30 mg/kg, every alternate day for 42 days), complete protection from seizures was observed with nano sodium valproate (∼150 mg/kg and ∼75 mg/kg of sodium valproate) and standard sodium valproate (300 mg/kg). Similarly, significant protection from behavioral impairment and oxidative stress was observed with standard sodium valproate and nano sodium valproate as compared to PTZ.

CONCLUSION

When compared to conventional therapy, nano sodium valproate showed protection from seizures at reduced doses and for a longer duration in animal models of epilepsy. This study suggests the potential of nano sodium valproate in the treatment of epilepsy.

Hyperammonemia in a Woman with Late-onset Ornithine Transcarbamylase Deficiency

A 52-year-old woman developed vomiting and disturbance of consciousness after consuming raw fish and sushi on a trip. A blood test showed hyperammonemia (310 μg/dL) with a normal liver function. She fell into a deep coma, and her serum ammonia level increased to 684 μg/dL. L-arginine was administered as a diagnostic treatment for urea cycle disorder (UCD) and serum ammonia, and her consciousness levels improved. She was diagnosed with ornithine transcarbamylase deficiency (OTCD) by analyses of plasma amino acids, urinary orotic acid, and the OTC gene mutation. UCD should be considered for patients with hyperammonemia without severe liver function abnormalities.

Improved assay protocol for measurement of ammonia on the Roche Cobas 8000 automated platform

Introduction

Ammonia is a metabolite of protein catabolism that, when elevated, may be toxic for tissues, especially for the central nervous system. Elevated ammonia in blood is an indicator and a prognostic factor for hepatic and kidney disease or inherited metabolic disorders in nitrogen metabolism. The accuracy of ammonia determination is influenced by sampling condition, handling, storage and assay itself. Our and other laboratories have been experiencing high frequencies sample error flags while measuring ammonia with glutamate dehydrogenase method on Roche Cobas 8000 platform. To reduce the number of error flags we adapted Roche NH3L protocol by incorporation of an additional onboard routine step for sample pre-dilution.

Material and methods

The AMC NH3L is an adaptation of Roche protocol that uses four fold pre-dilution of the sample in the rerun prior to the analysis. It was assessed for 1.occurrence of absorbance error flags, 2.precision, 3.correlation with Roche method and 4.interference by hemolysis, icterus and lipemia.

Results

The AMC NH3L adaptation demonstrates acceptable within-run and total precision. Comparison studies show no differences between the Roche rerun application and AMC NH3L adaptation. The AMC NH3L adaptation solves 78% of absorbance errors and for samples with high ammonia concentration is less affected by interferences from icterus and hemolysis than the Roche rerun application.

Conclusion

The AMC NH3L adaptation is less prone to instrument error flags and for samples with high ammonia concentration, is more robust to endogenous interferences. The AMC NH3L adaptation is viable alternative to the Roche protocol for the ammonia measurement.

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Ammonia measurement on Roche Cobas 8000 suffers from 11,3% sample absorbance error flags for exceeding the absorbance limits on the detector.

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AMC NH3L adaptation solves 78% of absorbance errors of Roche method and forhigh ammonia concentration, is more robust to endogenous inferences.

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AMC NH3L adaptation is a viable alternative to the Roche protocol for the ammonia measurement.

Valproic acid induced acute liver injury resulting in hepatic encephalopathy- a case report and literature review

Valproic acid (VPA) is a commonly used agent in the management of seizures and psychiatric disorders. Hyperammonemia is a common complication of VPA with 27.8% of patients having elevated levels – that is unrelated to hepatotoxicity and normal transaminases. Common side effects include obesity, insulin resistance, metabolic disorder and severe forms of hepatotoxicity. Other rare and idiosyncratic reactions have been reported, one of which is presented in our case. A 27-year old patient presented with hyperammonemia and encephalopathy as a consequence of idiosyncratic VPA reaction causing drug-induced liver injury (DILI) with severely elevated transaminases. DILI is commonly overlooked when investigating encephalopathy in the setting of VPA. Physicians should consider DILI in the context of hyperammonemia and transaminitis.

Risk Factors for Valproic Acid-induced Hyperammonaemia in Chinese Paediatric Patients with Epilepsy

This study was aimed at identifying genetic and non-genetic risk factors for valproic acid (VPA)-induced hyperammonaemia in Chinese paediatric patients with epilepsy. A total of 210 epileptic patients, treated with VPA as monotherapy, were enrolled and classified into hyperammonaemia and control groups according to their blood ammonia level (cut-off value 50 μmol/L). Serum concentrations of VPA and its major metabolites were simultaneously determined by ultrahigh-performance liquid chromatography-tandem mass spectrometry. Six single nucleotide polymorphisms in the candidate genes, CYP2C9, CYP2A6, CYP2B6 and CPS1, were analysed by a matrix-assisted laser desorption ionization-time of flight mass spectrometry method or nested PCR. Significant differences in age, aspartate transaminase level and the incidence of liver injury were observed between patients of hyperammonaemia and control groups. Genotype distributions of CYP2C9*3, CYP2A6*4 and CPS1 4217C>A allelic variants were also significantly different between the two groups. According to multiple regression analysis, a significant negative correlation was detected between age and the blood ammonia level, while liver injury, the concentration-dose ratio (CDR) of VPA and 2-propyl-4-pentenoic acid (4-ene VPA), and the presence of CYP2A6*4 or CPS1 4217C>A showed positive correlations with the blood ammonia level. In addition, the risk factors for hyperammonaemia identified by logistic regression analysis were as follows: a younger age (odds ratio [OR] = 0.85; 95% confidence interval [CI] = 0.76-0.96; p = 0.007), occurrence of liver injury (OR = 4.60; 95% CI = 1.27-16.74; p = 0.021), higher CDR of 4-ene VPA (OR = 1.08; 95% CI = 1.03-1.14; p = 0.001), and carrying mutant alleles of CYP2C9*3 (OR = 3.42; 95% CI = 1.15-10.19; p = 0.028), CYP2A6*4 (OR = 3.23; 95% CI = 1.40-7.48; p = 0.006) and CPS1 4217C>A (OR = 3.25; 95% CI = 1.52-6.94; p = 0.002). Our findings indicated that multiple genetic and non-genetic risk factors that were identified can be used to predict the development of VPA-induced hyperammonaemia in Chinese paediatric patients with epilepsy.

Gait instability in valproate-treated patients: Call to measure ammonia levels

OBJECTIVE

Hyperammonemia induced by valproate (VPA) treatment may lead to several neurological and systemic symptoms as well as to seizure exacerbation. Gait instability and recurrent falls are rarely mentioned as symptoms, especially not as predominant ones.

METHODS

We report five adult patients with frontal lobe epilepsy (FLE) who were treated with VPA and in whom a primary adverse effect was unstable gait and falls.

RESULTS

There were four males and one female patients with FLE, 25-42-year-old, three following epilepsy surgery. All of them were treated with antiepileptic drug polytherapy. Gait instability with falls was one of the principal sequelae of the treatment. Patients also exhibited mild encephalopathy (all patients) and flapping tremor (three patients) that developed following the addition of VPA (three patients) and with chronic VPA treatment (two patients). VPA levels were within the reference range. Serum ammonia levels were significantly elevated (291-407 μmole/L, normal 20-85) with normal or slightly elevated liver enzymes. VPA dose reduction or discontinuation led to the return of ammonia levels to normal and resolution of the clinical symptoms, including seizures, which disappeared in two patients and either decreased in frequency or became shorter in duration in the other three.

CONCLUSIONS

Gait instability due to hyperammonemia and VPA treatment is probably under-recognized in many patients. It can develop when the VPA levels are within the reference range and with normal or slightly elevated liver enzymes.

Sudden valproate-induced hyperammonemia managed with L-carnitine in a medically healthy bipolar patient: Essential review of the literature and case report

RATIONALE

Valproic Acid is a commonly used psychiatric drug primarily used as a mood stabilizer. Mild hyperammonemia is a Valproic Acid common adverse effect. This report presents an example of treated hyperammonemia on Valproic acid therapy managed with L-carnitine administration in BD patients characterized by sudden vulnerability.

PATIENT CONCERNS

We report the case of a 29-year-old man suffering from bipolar disorder (BD) and substance use disorder who exhibited sudden altered mental status upon admittance to the inpatient unit. The patient was started on Valproic acid with no improvement.

DIAGNOSES

The patient had remarkably high ammonia levels (594 μg/dL) without hepatic insufficiency, likely due to his valproate treatment.

INTERVENTIONS

The patient was administered lactulose, intravenous hydration, and i.v. levocarnitine supplementation 4.5 g/day.

OUTCOMES

The administration leads to reduction of ammonia levels to 99 μg/dL within 12 hours upon initiation of carnitine therapy and progressive restore of his mental status within 24 hours.

LESSONS

Resolution of hyperammonemia caused by Valproic acid therapy may be enhanced with the administration of L-carnitine. An interesting aspect of this case was how rapidly the patient responded to the carnitine therapy.

Should Pharmacies Be Included in Medication Reconciliation? A Report of Recurrent Valproic Acid Toxicity

Including outpatient pharmacies in the medication reconciliation process upon hospital discharge is not commonly performed. This case highlights the consequences of a patient refilling a discontinued prescription for valproic acid (VPA). We present a 32-year old male found unresponsive after ingesting delayed release divalproex sodium. Cerebral edema was visualized on magnetic resonance imaging. Hemodialysis and levo-carnitine treatment led to improved mental status, and VPA was discontinued. The same patient presented with VPA overdose eight months later after he continued to fill an outdated prescription. This case highlights consequences of VPA toxicity; it also demonstrates an opportunity to improve patient safety and high-value care by collaborating with outpatient pharmacies in the medication reconciliation process upon hospital discharge.

Valproate induced hyperammonemic encephalopathy treated by haemodialysis

Valproate (VPA)-induced hyperammonemic encephalopathy is an unusual, but serious, adverse effect of divalproex sodium (DVPX) treatment and if untreated can lead to raised intracranial pressure, seizures, coma, and eventually death. It can, however, be reversed if an early diagnosis is made. It is therefore extremely important to recognize it and discontinue DVPX treatment. Our patient developed sudden deterioration of sensorium, drowsiness, lethargy, and later severe comatose state after few days of starting DVPX with high levels of serum ammonia despite therapeutic levels of VPA and normal liver function test. He responded to hemodialysis, cerebral decongestants, and other intensive supportive measures.

Valproic Acid Induced Hyperammonemia in a Long Time Treated Patient

We report a case of a patient who had been on long time valproic acid for treatment of bipolar affective disorder. While being an inpatient, serology ammonia level testing revealed a very high ammonia level despite being asymptomatic. Dual therapy of carnitine and lactulose was provided to the patient for treatment of the hyperammonemia. It should also be noted that, during this treatment, valproic acid was not stopped. Consequently, this case illustrates that patients can present asymptomatically despite very high ammonia levels and hyperammonemia can occur in chronic valproic acid despite not increasing the dose of the medication and psychiatrists do not need to discontinue valproic acid in the presence of elevated levels of ammonia if the patient shows no signs of encephalopathy or delirium.

Carnitine and/or Acetylcarnitine Deficiency as a Cause of Higher Levels of Ammonia

Blood carnitine and/or acetylcarnitine deficiencies are postulated in the literature as possible causes of higher ammonia levels. The aim of this study was to investigate if the use of valproic acid, the age of the patients, or certain central nervous system pathologies can cause carnitine and/or acetylcarnitine deficiency leading to increased ammonia levels. Three groups of patients were studied: (A) epileptic under phenytoin monotherapy (n = 31); (B) with bipolar disorder under valproic acid treatment (n = 28); (C) elderly (n = 41). Plasma valproic acid and blood carnitine and acyl carnitine profiles were determined using a validated HPLC and LC-MS/MS method, respectively. Blood ammonia concentration was determined using an enzymatic automated assay. Higher ammonia levels were encountered in patients under valproic acid treatment and in the elderly. This may be due to the lower carnitine and/or acetylcarnitine found in these patients. Patients with controlled seizures had normal carnitine and acetylcarnitine levels. Further studies are necessary in order to conclude if the uncontrolled bipolar disorder could be the cause of higher carnitine and/or acetylcarnitine levels.

Valproate Induced Hyperammonemic Delirium

Sodium valproate induced hyperammonaemic delirium with normal liver function tests is a relatively uncommon adverse effect. It may be mistaken for psychosis or worsening of mania leading to wrong diagnosis and improper management. Plasma ammonia levels should be monitored in all patients developing altered mental status after receiving valproate therapy. This is a case series of hyperammonaemic delirium due to valproate reported to the Department of Pharmacology from Department of Psychiatry over a period of one year.

A report on older-age bipolar disorder from the International Society for Bipolar Disorders Task Force

OBJECTIVES

In the coming generation, older adults with bipolar disorder (BD) will increase in absolute numbers as well as proportion of the general population. This is the first report of the International Society for Bipolar Disorder (ISBD) Task Force on Older-Age Bipolar Disorder (OABD).

METHODS

This task force report addresses the unique aspects of OABD including epidemiology and clinical features, neuropathology and biomarkers, physical health, cognition, and care approaches.

RESULTS

The report describes an expert consensus summary on OABD that is intended to advance the care of patients, and shed light on issues of relevance to BD research across the lifespan. Although there is still a dearth of research and health efforts focused on older adults with BD, emerging data have brought some answers, innovative questions, and novel perspectives related to the notion of late onset, medical comorbidity, and the vexing issue of cognitive impairment and decline.

CONCLUSIONS

Improving our understanding of the biological, clinical, and social underpinnings relevant to OABD is an indispensable step in building a complete map of BD across the lifespan.

Ammonia metabolism and hyperammonemic disorders

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.

Hyperammonemic Encephalopathy due to Valproic Acid and Topiramate Interaction

Valproic acid-induced hyperammonemic encephalopathy is a rare yet serious adverse drug reaction. Medication interactions such a valproic acid and topiramate can precipitate an event. We present the case of a 52-year-old female that presented with acute mental status change and hypersomnolence due to hyperammonemia caused by a valproic acid derivative. The patient improved after withdrawal of the offending medications and treatment with lactulose. Clinicians should remain hypervigilant in monitoring for valproic acid-induced hyperammonemic encephalopathy and risk factors such as polypharmacy.

Hyperammonemia associated with valproic acid concentrations

Valproic acid, a branched short-chain fatty acid, has numerous action mechanisms which turn it into a broad spectrum anticonvulsant drug and make its use possible in some other pathologies such as bipolar disorder. It is extensively metabolized in liver, representing β-oxidation in the mitochondria one of its main metabolic route (40%). Carnitine is responsible for its entry into the mitochondria as any other fatty acid. Long-term high-dose VPA therapy or acute VPA overdose induces carnitine depletion, resulting in high levels of ammonia in blood. As a high correlation between salivary valproic acid levels and plasma ultrafiltrate levels was found in humans, saliva becomes a promising monitoring fluid in order to study valproic acid pharmacokinetics and its toxic effect. Extended-release (twice daily) formulations of valproic acid or carnitine supplementation are the proposed two therapeutic strategies in order to reverse hyperammonemia.

Comparative modeling and virtual screening for the identification of novel inhibitors for myo-inositol-1-phosphate synthase

Myo-inositol-1-phosphate (MIP) synthase is a key enzyme in the myo-inositol biosynthesis pathway. Disruption of the inositol signaling pathway is associated with bipolar disorders. Previous work suggested that MIP synthase could be an attractive target for the development of anti-bipolar drugs. Inhibition of this enzyme could possibly help in reducing the risk of a disease in patients. With this objective, three dimensional structure of the protein was modeled followed by the active site prediction. For the first time, computational studies were carried out to obtain structural insights into the interactive behavior of this enzyme with ligands. Virtual screening was carried out using FILTER, ROCS and EON modules of the OpenEye scientific software. Natural products from the ZINC database were used for the screening process. Resulting compounds were docked into active site of the target protein using FRED (Fast Rigid Exhaustive Docking) and GOLD (Genetic Optimization for Ligand Docking) docking programs. The analysis indicated extensive hydrogen bonding network and hydrophobic interactions which play a significant role in ligand binding. Four compounds are shortlisted and their binding assay analysis is underway.

Valproate-induced hyperammonemia in juvenile ceroid lipofuscinosis (Batten disease)

PURPOSE

Valproate-induced hyperammonemia (VHA) and hyperammonemic encephalopathy (VHE) are well-known complications of valproate (VPA) treatment. Currently recognised risk factors for VHE include a high VPA dosage, the need for polytherapy and long duration of treatment. Despite the severe nature of the epilepsy, presence of concomitant psychiatric manifestations, and frequent need for poly-pharmacy associated with juvenile ceroid lipofuscinosis (JNCL, Batten disease) neither this disorder nor other subtypes of neuronal ceroid lipofuscinosis have previously been identified as risk factors for VHA/VHE. The aim of the present publication is to describe four cases with VHE in a well-defined Danish population of JNCL.

METHOD

An examination of medical records of all 35 patients with JNCL in Denmark was conducted and revealed fourteen patients treated with VPA.

RESULTS

Four patients treated with VPA developed VHE. All patients were prescribed VPA in standard dosages, had normal plasma concentrations of VPA and received antiepileptic drug (AED) polytherapy. Symptoms occurred shortly after commencement or increase in dose of VPA, and were quickly reversible upon discontinuation of VPA. Carnitine supplement was administrated in two patients, which resulted in resolution of symptoms and normalized ammonium levels.

CONCLUSION

Patients with JNCL are in great risk of developing VHA and VHE due to a high rate of polytherapy. Furthermore, studies have shown that carnitine level can be depressed in JNCL, which may increase the risk of VHA and VHE. We recommend that increased attention should be given to these patients.

Drug-induced liver injury from antiepileptic drugs

Drug-induced liver injury is a potential complication of innumerable medications. Most cases do not occur in a predictable, dose-dependent manner, leading to delayed recognition of a drug's hepatotoxic potential until after its release into the market. The estimated occurrence is 1 in 10,000 to 100,000 patients. However, the rates are likely higher because many cases go unrecognized owing to lack of reporting or missed diagnosis. This article reviews the most commonly associated antiepileptic drugs.