Successful treatment by direct hemoperfusion of coma possibly resulting from mitochondrial dysfunction in acute valproate intoxication

The serum acylcarnitines profile in epileptic children treated with valproic acid and the protective roles of peroxisome proliferator-activated receptor a activation in valproic acid-induced liver injury

Valproic acid (VPA) is widely used as a major drug in the treatment of epilepsy. Despite the undisputed pharmacological importance and effectiveness of VPA, its potential hepatotoxicity is still a major concern. Being a simple fatty acid, the hepatotoxicity induced by VPA has long been considered to be due primarily to its interference with fatty acid β-oxidation (β-FAO). The aim of this study was to investigate the biomarkers for VPA-induced abnormal liver function in epileptic children and to determine potential mechanisms of its liver injury. Targeted metabolomics analysis of acylcarnitines (ACs) was performed in children's serum. Metabolomic analysis revealed that VPA -induced abnormal liver function resulted in the accumulation of serum long-chain acylcarnitines (LCACs), and the reduced expression of β-FAO relevant genes (Carnitine palmitoyltrans-ferase (CPT)1, CPT2 and Long-chain acyl-CoA dehydrogenase (LCAD)), indicating the disruption of β-FAO. As direct peroxisome proliferator-activated receptor a (PPARα)- regulated genes, CPT1A, CPT2 and LCAD were up-regulated after treatment with PPARα agonist, fenofibrate (Feno), indicating the improvement of β-FAO. Feno significantly ameliorated the accumulation of various lipids in the plasma of VPA-induced hepatotoxic mice by activating PPARα, significantly reduced the plasma ACs concentration, and attenuated VPA-induced hepatic steatosis. Enhanced oxidative stress and induced by VPA exposure were significantly recovered using Feno treatment. In conclusion, this study indicates VPA-induced β-FAO disruption might lead to liver injury, and a significant Feno protective effect against VPA -induced hepatotoxicity through reversing fatty acid metabolism.

Extracorporeal treatment for valproic acid poisoning: systematic review and recommendations from the EXTRIP workgroup

BACKGROUND

The EXtracorporeal TReatments In Poisoning (EXTRIP) workgroup presents its systematic review and clinical recommendations on the use of extracorporeal treatment (ECTR) in valproic acid (VPA) poisoning.

METHODS

The lead authors reviewed all of the articles from a systematic literature search, extracted the data, summarized the key findings, and proposed structured voting statements following a predetermined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements and the RAND/UCLA Appropriateness Method was used to quantify disagreement. Anonymous votes were compiled, returned, and discussed in person. A second vote was conducted to determine the final workgroup recommendations.

RESULTS

The latest literature search conducted in November 2014 retrieved a total of 79 articles for final qualitative analysis, including one observational study, one uncontrolled cohort study with aggregate analysis, 70 case reports and case series, and 7 pharmacokinetic studies, yielding a very low quality of evidence for all recommendations. Clinical data were reported for 82 overdose patients while pharmaco/toxicokinetic grading was performed in 55 patients. The workgroup concluded that VPA is moderately dialyzable (level of evidence = B) and made the following recommendations: ECTR is recommended in severe VPA poisoning (1D); recommendations for ECTR include a VPA concentration > 1300 mg/L (9000 μmol/L)(1D), the presence of cerebral edema (1D) or shock (1D); suggestions for ECTR include a VPA concentration > 900 mg/L (6250 μmol/L)(2D), coma or respiratory depression requiring mechanical ventilation (2D), acute hyperammonemia (2D), or pH ≤ 7.10 (2D). Cessation of ECTR is indicated when clinical improvement is apparent (1D) or the serum VPA concentration is between 50 and 100 mg/L (350-700 μmol/L)(2D). Intermittent hemodialysis is the preferred ECTR in VPA poisoning (1D). If hemodialysis is not available, then intermittent hemoperfusion (1D) or continuous renal replacement therapy (2D) is an acceptable alternative.

CONCLUSIONS

VPA is moderately dialyzable in the setting of overdose. ECTR is indicated for VPA poisoning if at least one of the above criteria is present. Intermittent hemodialysis is the preferred ECTR modality in VPA poisoning.

Miscellaneous central nervous system intoxicants

The topic of central nervous system intoxicants encompasses a multitude of agents. This article focuses on three classes of therapeutic drugs, with specific examples in which overdoses require admission to the intensive care unit. Included are some of the newer antidepressants, the atypical neuroleptic agents, and selected anticonvulsant drugs. The importance of understanding pertinent physiology and applicable supportive care is emphasized.

Valproate-induced hyperammonemic encephalopathy: an update on risk factors, clinical correlates and management

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.

Drug-induced toxicity on mitochondria and lipid metabolism: mechanistic diversity and deleterious consequences for the liver

Numerous investigations have shown that mitochondrial dysfunction is a major mechanism of drug-induced liver injury, which involves the parent drug or a reactive metabolite generated through cytochromes P450. Depending of their nature and their severity, the mitochondrial alterations are able to induce mild to fulminant hepatic cytolysis and steatosis (lipid accumulation), which can have different clinical and pathological features. Microvesicular steatosis, a potentially severe liver lesion usually associated with liver failure and profound hypoglycemia, is due to a major inhibition of mitochondrial fatty acid oxidation (FAO). Macrovacuolar steatosis, a relatively benign liver lesion in the short term, can be induced not only by a moderate reduction of mitochondrial FAO but also by an increased hepatic de novo lipid synthesis and a decreased secretion of VLDL-associated triglycerides. Moreover, recent investigations suggest that some drugs could favor lipid deposition in the liver through primary alterations of white adipose tissue (WAT) homeostasis. If the treatment is not interrupted, steatosis can evolve toward steatohepatitis, which is characterized not only by lipid accumulation but also by necroinflammation and fibrosis. Although the mechanisms involved in this aggravation are not fully characterized, it appears that overproduction of reactive oxygen species by the damaged mitochondria could play a salient role. Numerous factors could favor drug-induced mitochondrial and metabolic toxicity, such as the structure of the parent molecule, genetic predispositions (in particular those involving mitochondrial enzymes), alcohol intoxication, hepatitis virus C infection, and obesity. In obese and diabetic patients, some drugs may induce acute liver injury more frequently while others may worsen the pre-existent steatosis (or steatohepatitis).

Acute hemolysis with acute renal failure in a patient with valproic acid poisoning treated with charcoal hemoperfusion

Hemoperfusion consists of the passage of anticoagulated blood through a column containing adsorbent particles. It was introduced in 1940 and refined from 1950 to 1970, and then introduced clinically for the treatment of acute intoxications between 1970 and 1980. Life-threatening valproic acid toxicity is an indication for coated charcoal hemoperfusion usually accomplished without complications, but we report a case of acute severe intravascular hemolysis during the time of hemoperfusion with coated charcoal column.

Extracorporeal management of valproic acid toxicity: a case report and review of the literature

The incidence of intentional or accidental valproic acid (VPA) overdose is increasing. Severe VPA toxicity may lead to coma and death. Traditionally the treatment of patients with VPA toxicity has been limited to supportive measures. VPA is highly protein bound and therefore it is considered not to be removable by extracorporeal means. However, studies of VPA toxicokinetics indicate that at blood levels that exceed therapeutic concentrations, VPA protein binding sites become saturated, leading to increased concentration of the free unbound drug. The free unbound drug has a small molecular weight and therefore it is theoretically amenable to removal by extracorporeal means. We present a patient with VPA toxicity who was successfully treated with "in-series" hemodialysis and hemoperfusion followed by continuous venovenous hemodiafiltration (CVVHDF) and review the literature on the management of VPA toxicity using extracorporeal therapies.

Science review: carnitine in the treatment of valproic acid-induced toxicity - what is the evidence?

Valproic acid (VPA) is a broad-spectrum antiepileptic drug and is usually well tolerated, but rare serious complications may occur in some patients receiving VPA chronically, including haemorrhagic pancreatitis, bone marrow suppression, VPA-induced hepatotoxicity (VHT) and VPA-induced hyperammonaemic encephalopathy (VHE). Some data suggest that VHT and VHE may be promoted by carnitine deficiency. Acute VPA intoxication also occurs as a consequence of intentional or accidental overdose and its incidence is increasing, because of use of VPA in psychiatric disorders. Although it usually results in mild central nervous system depression, serious toxicity and even fatal cases have been reported. Several studies or isolated clinical observations have suggested the potential value of oral L-carnitine in reversing carnitine deficiency or preventing its development as well as some adverse effects due to VPA. Carnitine supplementation during VPA therapy in high-risk patients is now recommended by some scientific committees and textbooks, especially paediatricians. L-carnitine therapy could also be valuable in those patients who develop VHT or VHE. A few isolated observations also suggest that L-carnitine may be useful in patients with coma or in preventing hepatic dysfunction after acute VPA overdose. However, these issues deserve further investigation in controlled, randomized and probably multicentre trials to evaluate the clinical value and the appropriate dosage of L-carnitine in each of these conditions.

Épuration extrarénale, supplémentation en L-carnitine et intoxication à l’acide valproïque

We report the case of a severe valproic acid poisoning in a 36-year-old man. In front of a high serum concentration of valproic acid at the admission, haemodialysis was initiated to decrease serum valproic acid concentration. A L-carnitine therapy (50 mg/kg per day) was also started. A cerebral oedema appeared at the third day, but the patient recovered without any sequela.

Valproic acid toxicity: overview and management

Acute valproic acid intoxication is an increasing problem, accounting for more than 5000 calls to the American Association of Poison Control Centers in 2000. The purpose of this paper is to review the pharmacology and toxicology of valproic acid toxicity. Unlike earlier antiepileptic agents, valproic acid appears to function neither through sodium channel inhibition nor through direct gamma-aminobutyric acid agonism, but through an indirect increase in regional brain gamma-aminobutyric acid levels. Manifestations of acute valproic acid toxicity are myriad, and reflect both exaggerated therapeutic effect and impaired intermediary metabolism. Central nervous system depression is the most common finding noted in overdose, and may progress to coma and respiratory depression. Cerebral edema has also been observed. Although hepatotoxicity is rare in the acute overdose setting, pancreatitis and hyperammonemia have been reported. Metabolic and hematologic derangements have also been described. Management of acute valproic acid ingestion requires supportive care and close attention to the airway. The use of controversial adjunctive therapies, including extracorporeal drug elimination and L-carnitine supplementation, will be discussed.

Mitochondrial disease: a pulmonary and critical-care medicine perspective

The clinical spectrum of mitochondrial diseases has expanded dramatically in the last decade. Abnormalities of mitochondrial function are now thought to participate in a number of common adult diseases, ranging from exercise intolerance to aging. This review outlines the common presentations of mitochondrial disease in ICUs and in the outpatient setting and discusses current diagnostic and therapeutic options as they pertain to the pulmonary and critical-care physician.

Multicenter case series of valproic acid ingestion: serum concentrations and toxicity

BACKGROUND

Valproic acid exposures reported to poison centers have increased more than 4-fold over the last 5 years. There are no large case series published on valproic acid ingestion.

METHODS

A prospective multicenter case series of all patients reporting an ingestion of valproic acid. Data collected included: age, gender, dose ingested, concomitant medications, symptoms and vital signs, laboratory values, length of hospital stay, and medical outcome. Entrance into the study required a serum valproic acid concentration above the therapeutic threshold of 100 microg/mL. Statistical analysis was by Fisher's exact test.

RESULTS

A total of 335 patients were reported to participating centers of which 186 (55%) had serum valproic acid concentrations greater than 100 microg/mL. Of the 186 cases, 53 were multiple drug exposures leaving 133 cases of sole valproic acid ingestion for evaluation. Age ranged from 2 to 66 years with a mean of 30.1 years +/- 12. Peak serum valproic acid concentrations ranged from 110 microg/mL to 1840 microg/mL with a mean of 378.3 microg/mL +/- 310.2 microg/mL. Time from postingestion to the peak measured valproic acid concentration ranged from 1 to 18 hours, with a mean of 7.4 hours +/- 3.9. Symptoms included lethargy (n = 94), coma (n = 19), tachycardia (n = 24), aspiration (n = 8), metabolic acidosis (n = 8), and hypotension (n = 4). A peak concentration of > 450 microg/mL was more likely to be associated with a moderate or major adverse outcome (p < 0.005). A peak concentration > 850 microg/mL was more likely to be associated with coma (p < 0.005) and acidosis (p < 0.005). Eleven patients experienced transient thrombocytopenia (platelets < 150,000) and all had peak valproic acid concentrations >450 microg/mL. Four patients experienced transient leukopenia (WBC < 3,500). The mean hospital stay for all patients was 42 +/- 33.1 hours. A hospital stay > 48 hours was more likely to be associated with a peak valproic acid concentration > 450 microg/mL (p < 0.05). There were 2 fatalities.

CONCLUSIONS

In this case series, patients with peak valproic acid concentrations above 450 microg/mL were more likely to develop significant clinical effects and have longer hospital stays. A peak valproic acid concentration above 850 microg/mL was more likely to be associated with coma, respiratory depression, aspiration, or metabolic acidosis.