Therapeutic Management of Idiosyncratic Drug-Induced Liver Injury and Acetaminophen Hepatotoxicity in the Paediatric Population: A Systematic Review

Introduction

Drug-induced liver injury (DILI) is a rare but serious adverse event that can progress to acute liver failure (ALF). The evidence for treatment of DILI in children is scarce.

Objective

We aimed to comprehensively review the available literature on the therapies for both acetaminophen overdose (APAP) and idiosyncratic DILI in the paediatric population.

Methods

We included original articles conducted in a paediatric population (< 18 years) in which a therapeutic intervention was described to manage APAP or idiosyncratic DILI. Findings were summarized based on age groups (preterm newborn neonates, term and post-term neonates, infants, children and adolescents).

Results

Overall, 25 publications (fifteen case reports, six case series and four retrospective cohort studies) were included, including a total of 140 paediatric DILI cases, from preterm newborn neonates to adolescents. N-acetylcysteine was used to treat 19 APAP cases. N-acetylcysteine (n = 14), ursodeoxycholic acid (n = 3), corticosteroids (n = 31), carnitine (n = 16) and the combination of glycyrrhizin, reduced glutathione, polyene phosphatidylcholine and S-adenosylmethionine (n = 31) were the therapeutic options for treating idiosyncratic DILI. The molecular adsorbent recirculating system was used in the management of either APAP (n = 4) or idiosyncratic DILI (n = 2), while 20 paediatric ALF cases received continuous renal replacement therapy.

Conclusions

This systematic review identified DILI in the paediatric population who have received specific treatment. These interventions appear to be mainly extrapolated from low-quality evidence from the adult population. Thus, there is a need for high-quality studies to test the efficacy of known and novel therapies to treat DILI specifically addressed to the paediatric population.

PROSPERO registration number CRD42021214702.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40264-022-01224-w.

Managing valproic acid toxicity-related hyperammonaemia: an unpredicted course

A 20-year-old woman presented following an intentional overdose of valproic acid. Use of valproic acid, either acute or chronic, can result in hyperammonaemia. Mild hyperammonaemia with chronic use is mostly asymptomatic but can also present with concern for encephalopathy. Acute valproic acid toxicity results in significant hyperammonaemia, which can contribute to encephalopathy. Levocarnitine is the treatment of choice in valproic acid toxicity-related hyperammonaemia. For severe cases of encephalopathy, intermittent haemodialysis can also be considered. To our knowledge, this is the first case report to clearly show symptom relapse and hyperammonaemia after discontinuing levocarnitine. We recommend levocarnitine therapy for at least 72 hours, followed by an additional 24 hours of monitoring for symptom relapse and hyperammonaemia after levocarnitine discontinuation.

Drug-induced liver injury: Asia Pacific Association of Study of Liver consensus guidelines

Idiosyncratic drug-induced liver injury mimics acute and chronic liver disease. It is under recognized and underrecognised because of the lack of pathognomonic diagnostic serological markers. Its consequences may vary from being asymptomatic to self-limiting illness to severe liver injury leading to acute liver failure. Its incidence is likely to be more common in Asia than other parts of the world, mainly because of hepatotoxicity resulting from the treatment of tuberculosis disease and the ubiquitous use of traditional and complimentary medicines in Asian countries. This APASL consensus guidelines on DILI is a concise account of the various aspects including current evidence-based information on DILI with special emphasis on DILI due to antituberculosis agents and traditional and complementary medicine use in Asia.

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.

Antiepileptic Drugs and Liver Disease

Acute, symptomatic seizures or epilepsy may complicate the course of hepatic disease. Choosing the most appropriate antiepileptic drug in this setting represents a difficult challenge, as most medications are metabolized by the liver. This article focuses on the acute and chronic treatment of seizures in patients with advanced liver disease and reviews the hepatotoxic potential of specific antiepileptic drugs. Newer antiepileptic drugs without, or with minimal, hepatic metabolism, such as levetiracetam, lacosamide, topiramate, gabapentin, and pregabalin should be used as first-line therapy. Medications undergoing extensive hepatic metabolism, such as valproic acid, phenytoin, and felbamate should be used as drugs of last resort. In special circumstances, as in patients affected by acute intermittent porphyria, exposure to most antiepileptic drugs could precipitate attacks. In this clinical scenario, bromides, levetiracetam, gabapentin, and vigabatrin constitute safe choices. For the treatment of status epilepticus, levetiracetam and lacosamide, available in intravenous preparations, are good second-line therapies after benzodiazepines fail to control seizures. Hepatotoxicity is also a rare and unexpected side effect of some antiepileptic drugs. Drugs such as valproic acid, phenytoin, and felbamate, have a well-recognized association with liver toxicity. Other antiepileptic drugs, including phenobarbital, benzodiazepines, ethosuximide, and the newer generations of antiepileptic drugs, have only rarely been linked to hepatotoxicity. Thus physicians should be mindful of the pharmacokinetic profile and the hepatotoxic potential of the different antiepileptic drugs available to treat patients affected by liver disease.

Valproic Acid Overdose Review of a Case With Electrocardiographic Changes

BACKGROUND

Valproic acid (VPA) is increasingly used to treat a variety of medical disorders, such as seizures, psychiatric disorders, and headaches. Therefore, accidental and intentional ingestions with valproic acid are increasing.

OBJECTIVES

A case is presented in an adolescent with ischemic electrocardiographic changes after an acute overdose with VPA.

DISCUSSION

Major features of a valproic acid overdose include respiratory depression, progressive coma, hepatotoxicity, thrombocytopenia, and hemodynamic instability. Electrocardiographic abnormalities usually consist of tachycardia and nonspecific changes. Supportive care is indicated in most overdoses and involves the monitoring and correction of electrolyte abnormalities, coagulopathies, and acid-base imbalances. Treatment may include activated charcoal, naloxone, l-carnitine, and extracorporeal detoxification.

CONCLUSIONS

Valproic acid overdose is a relatively rare and electrocardiographic changes usually consist of tachycardia and nonspecific changes, but ischemic changes may occur and usually transient and require only recognition.

L-Arginine in the treatment of valproate overdose - five clinical cases

BACKGROUND

Valproic acid and its metabolites - particularly valproyl-CoA - are inhibitors of the enzyme N-acetylglutamate synthetase. The amino acid l-arginine can stimulate N-acetylglutamate synthetase activity and could be potentially used therapeutically to correct hyperammonemia caused by valproate therapy or overdose. Severely valproic-acid-poisoned patients are usually treated with l-carnitine or hemodialysis in order to decrease hyperammonemia. We herein report of five cases, in which l-arginine was administered.

METHODS

Observational study on five cases. Patients with hyperammonemia (i.e., ammonia 80 > μg/dL) and symptoms consistent with valproate overdose (i.e., drowsiness, coma) were selected for treatment with l-arginine. Data was collected retrospectively.

RESULTS

l-Arginine decreased ammonia levels in a close temporal relation (case I ammonia in EDTA-plasma [μg/dL] decreased from 381 to 39; case II from 281 to 50; case III from 669 to 74; case IV from 447 to 56; case V from 202 to 60). In cases I and II, hemodialysis was performed and l-carnitine was given before the administration of l-arginine. In case III, hemodialysis was performed after the administration of l-arginine was already started. In cases IV and V, treatment with l-arginine was the sole measure to decrease ammonia levels in plasma.

CONCLUSION

The results suggest that l-arginine may be beneficial in selected cases of valproate overdose complicated by hyperammonemia. l-Arginine could extend our conventional treatment options for valproic acid overdose.

Favorable results after conservative management of 316 valproate intoxicated patients

Background:

Valproic acid (VPA) is an effective antiepileptic drug widely used worldwide. Despite several studies indicating the usefulness of intravenous L-carnitine in the treatment of VPA poisoning, this drug is not readily available in Iran. The aim of this study was to determine whether supportive care without antidote would result in acceptable outcomes in VPA poisoned patients.

Materials and Methods:

In an observational, retrospective, single-center case series, all patients >12-year-old with VPA overdose who had referred to a tertiary center between 2009 and 2013 were consecutively enrolled. Patients’ demographic and presenting features, physical examinations, clinical management, laboratory data, and outcomes were recorded.

Results:

A total of 316 patients were enrolled with pure VPA toxicity. The most common presenting signs/symptoms were drowsiness, nausea and vomiting, vertigo, and headache. In the course of the disease, 14 patients (4.4%) were intubated and three (0.9%) required hemodialysis with mean dialysis sessions of two. Fourteen patients were admitted to Intensive Care Unit, and seizures occurred in five. The initial level of consciousness was lower in patients with poor outcome. The median ingested dose of VPA in patients who required dialysis was significantly higher (20 vs. 6 g; P = 0.006). Multivariate analyses revealed that coma on presentation was associated with a worse outcome (P = 0.001; odds ratio = 61.5, 95% CI = 5.8-646.7).

Conclusion:

Prognosis of VPA poisoned patients appears to be good even with supportive care. According to our study, older age, ingestion of higher amounts of VPA and lower PCO₂, HCO₃, base excess, and CPK levels prone the patients to more severe toxicities in univariate analysis, but the main poor prognostic factor is coma on presentation in multivariate analysis.

Posterior reversible encephalopathy syndrome in a survivor of valproate-induced acute liver failure: a case report

Introduction

Posterior reversible encephalopathy syndrome is an extremely rare radiological diagnosis that has not been reported previously in association with acute liver failure.

Case presentation

A 6-year-old Sri Lankan girl developed acute liver failure with severe hepatic encephalopathy due to sodium valproate. She was successfully treated medically with N-acetylcysteine and L-carnitine. During recovery she again developed features of encephalopathy and had repeated convulsions associated with moderate hypertension. The diagnosis of posterior reversible encephalopathy syndrome was made on clinical and radiological grounds and she showed a gradual improvement with control of blood pressure.

Conclusions

This report adds to the evidence behind treatment of valproate-induced acute liver failure with N-acetylcysteine and L-carnitine and illustrates a rare but interesting association between acute liver failure and posterior reversible encephalopathy syndrome.

Valproate-induced hyperammonaemia superimposed upon severe neuropsychiatric lupus: a case report and review of the literature

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.

Noncirrhotic hyperammonaemic encephalopathy

Adult hyperammonaemia is associated with severe liver disease in 90% of cases. In the remainder, noncirrhotic causes should be considered. Measurements of serum ammonia level must be part of the basic work-up in all patients presenting with encephalopathy of unknown origin, even when liver function is normal. Clinician awareness of noncirrhotic hyperammonaemic encephalopathy can contribute to early diagnosis and the initiation of sometimes life-saving treatment. This review focuses on the physiology, aetiology and underlying mechanisms of noncirrhotic hyperammonaemic encephalopathy and discusses the available treatment modalities.

Evaluation of muscle strength and motor abilities in children with type II and III spinal muscle atrophy treated with valproic acid

Background

Spinal muscular atrophy (SMA) is an autosomal recessive disorder that affects the motoneurons of the spinal anterior horn, resulting in hypotonia and muscle weakness. The disease is caused by deletion or mutation in the telomeric copy of SMN gene (SMN1) and clinical severity is in part determined by the copy number of the centromeric copy of the SMN gene (SMN2). The SMN2 mRNA lacks exon 7, resulting in a production of lower amounts of the full-length SMN protein. Knowledge of the molecular mechanism of diseases has led to the discovery of drugs capable of increasing SMN protein level through activation of SMN2 gene. One of these drugs is the valproic acid (VPA), a histone deacetylase inhibitor.

Methods

Twenty-two patients with type II and III SMA, aged between 2 and 18 years, were treated with VPA and were evaluated five times during a one-year period using the Manual Muscle Test (Medical Research Council scale-MRC), the Hammersmith Functional Motor Scale (HFMS), and the Barthel Index.

Results

After 12 months of therapy, the patients did not gain muscle strength. The group of children with SMA type II presented a significant gain in HFMS scores during the treatment. This improvement was not observed in the group of type III patients. The analysis of the HFMS scores during the treatment period in the groups of patients younger and older than 6 years of age did not show any significant result. There was an improvement of the daily activities at the end of the VPA treatment period.

Conclusion

Treatment of SMA patients with VPA may be a potential alternative to alleviate the progression of the disease.

Trial Registration

ClinicalTrials.gov: NCT01033331

Adult nonhepatic hyperammonemia: a case report and differential diagnosis

This article presents a case report of nonhepatic hyperammonemia, i.e., elevated serum ammonia secondary to a nonhepatic etiology. It then discusses the importance of broadening one's differential diagnosis to include such nonhepatic causes of elevated ammonia levels, and provides a short review of rarer causes of hyperammonemia in the adult population. Treating the underlying condition is the best way to prevent recurrence of hyperammonemia. However, symptomatic treatment should not be delayed while investigating the underlying source.

L-Carnitine for Acute Valproic Acid Overdose: A Systematic Review of Published Cases

Objective:

To review the evidence supporting the efficacy and safety of l-carnitine in the management of acute valproic acid overdose. DATA SOURCES: MEDLINE (1950–May 2010), EMBASE (1980–May 2010), and Google Scholar (to May 2010) were searched, using the terms carnitine, valproic acid, and carnitine for valproic acid overdose. Reference citations from identified publications were reviewed.

Study Selection and Data Extraction:

Full-text publications evaluating the use of l-carnitine for management of valproic acid overdose in humans were sought. All studies, regardless of design, case series, and case reports reporting efficacy or safety endpoints were included. All languages were included. Two authors extracted primary data elements including patient demographics, presenting features, clinical management, and outcomes.

Data Synthesis:

Seven articles discussing 8 patients and 1 reporting safety data from records of 674 patients were reviewed. Reports covered both pediatric and adult patients with acute exposures to valproic acid mono- and polydrug overdose who were treated with various regimens of l-carnitine. All patients recovered clinically and no adverse effects were noted.

Conclusions:

Published evidence of the efficacy and safety of l-carnitine as an antidote for acute valproic acid overdose is limited. Based on the available evidence, it is reasonable to consider l-carnitine for patients with acute overdose of valproic acid who demonstrate decreased level of consciousness. We recommend intravenous administration of 100 mg/kg once, followed by infusions of 50 mg/kg (to a maximum of 3 g per dose) every 8 hours thereafter, continuing until ammonia levels are decreasing (if they were elevated initially) and the patient demonstrates signs of clinical improvement or until adverse events associated with l-carnitine occur.

Acute liver impairment after sodium valproate overdose

Liver impairment is a recognised adverse effect of long-term sodium valproate treatment, but there are few reports concerning its occurrence after acute overdose. This report describes a 36-year-old woman who deliberately ingested 32 g of sodium valproate (Epilim). Serum valproate concentration was 4370 μmol/l (630 mg/l) at 4.3 h post-ingestion (therapeutic reference range: 300-600 μmol/l), and the elimination half-life was 14.1 h. Liver biochemistry tests were initially normal but gradually became impaired, and highest alanine aminotransferase (761 U/l) occurred 2.3 days after ingestion. Supportive measures alone were sufficient to allow recovery of liver function. This case indicates that sodium valproate overdose may cause acute hepatocellular injury, even in the absence of pre-existing liver disease.