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

Management of acute carbamazepine poisoning: A narrative review

Standard management protocols are lacking and specific antidotes are unavailable for acute carbamazepine (CBZ) poisoning. The objective of this review is to provide currently available information on acute CBZ poisoning, including its management, by describing and summarizing various therapeutic methods for its treatment according to previously published studies. Several treatment methods for CBZ poisoning will be briefly introduced, their advantages and disadvantages will be analyzed and compared, and suggestions for the clinical treatment of CBZ poisoning will be provided. A literature search was performed in various English and Chinese databases. In addition, the reference lists of identified articles were screened for additional relevant studies, including non-indexed reports. Non-peer-reviewed sources were also included. In the present review, 154 articles met the inclusion criteria including case reports, case series, descriptive cohorts, pharmacokinetic studies, and in vitro studies. Data on 67 patients, including 4 fatalities, were reviewed. Based on the summary of cases reported in the included articles, the cure rate of CBZ poisoning after symptomatic treatment was 82% and the efficiency of hemoperfusion was 58.2%. Based on the literature review, CBZ is moderately dialyzable and the recommendation for CBZ poisoning is supportive management and gastric lavage. In severe cases, extracorporeal treatment is recommended, with hemodialysis as the first choice.

Management of Poisonings and Intoxications

Poisoning occurs after exposure to any of a number of substances, including medicines, which can result in severe toxicity including death. The nephrologist may be involved in poisonings that cause kidney disease and for targeted treatments. The overall approach to the poisoned patient involves the initial acute resuscitation and performing a risk assessment, whereby the exposure is considered in terms of the anticipated severity and in the context of the patient's status and treatments that may be required. Time-critical interventions such as gastrointestinal decontamination ( e.g. , activated charcoal) and antidotes are administered when indicated. The nephrologist is usually involved when elimination enhancement techniques are required, such as urine alkalinization or extracorporeal treatments. There is increasing data to guide decision making for the use of extracorporeal treatments in the poisoned patient. Principles to consider are clinical indications such as whether severe toxicity is present, anticipated, and/or will persist and whether the poison will be significantly removed by the extracorporeal treatment. Extracorporeal clearance is maximized for low-molecular weight drugs that are water soluble with minimal protein binding (<80%) and low endogenous clearance and volume of distribution. The dosage of some antidotes ( e.g. , N-acetylcysteine, ethanol, fomepizole) should be increased to maintain therapeutic concentrations once the extracorporeal treatment is initiated. To maximize the effect of an extracorporeal treatment, blood and effluent flows should be optimized, the filter with the largest surface area selected, and duration tailored to remove enough poison to reduce toxicity. Intermittent hemodialysis is recommended in most cases when an extracorporeal treatment is required because it is the most efficient, and continuous kidney replacement therapy is prescribed in some circumstances, particularly if intermittent hemodialysis is not readily available.

Valproate-Induced Hyperammonemic Encephalopathy Following Accidental Ingestion in a Toddler

Clinical manifestations of valproic acid (VPA) toxicity can range from just mild confusion and drowsiness to serious encephalopathy, leading to depressed sensorium and even coma and death. The exact cause(s) of how VPA influences the integrity of brain function remains unknown. Nevertheless, several mechanisms have been postulated including a surge in the blood ammonia concentration. Valproic acid-induced hyperammonemic encephalopathy is a rare yet serious sequalae and that can lead to grave outcomes. We report a case of hyperammonemic encephalopathy with preserved liver function following a moderate VPA intoxication in a toddler, who was successfully managed conservatively. Additionally, we briefly discuss mechanistic basis of VPA toxicity and highlight some of the available potential therapies.

Extracorporeal Treatment in the Management of Acute Poisoning: What an Intensivist Should Know?

Extracorporeal treatment (ECTR) represents a treatment modality promoting removal of endogenous or exogenous poisons and supporting or temporarily replacing a vital organ. This article aims to provide a brief overview of the technical aspects and the potential indications and limitations of the different ECTRs, highlighting the important characteristics of poison amenable to ECTR and the most appropriate prescriptions used in the setting of acute poisoning. The various principles that govern poison elimination by ECTR (diffusion, convection, adsorption, and centrifugation) and how components of the ECTR can be adjusted to maximize clearance have also being discussed.

Nanoporous biomaterials for uremic toxin adsorption in artificial kidney systems: A review

Hemodialysis, one of the earliest artificial kidney systems, removes uremic toxins via diffusion through a semipermeable porous membrane into the dialysate fluid. Miniaturization of the present hemodialysis system into a portable and wearable device to maintain continuous removal of uremic toxins would require that the amount of dialysate used within a closed-system is greatly reduced. Diffused uremic toxins within a closed-system dialysate need to be removed to maintain the optimum concentration gradient for continuous uremic toxin removal by the dialyzer. In this dialysate regenerative system, adsorption of uremic toxins by nanoporous biomaterials is essential. Throughout the years of artificial kidney development, activated carbon has been identified as a potential adsorbent for uremic toxins. Adsorption of uremic toxins necessitates nanoporous biomaterials, especially activated carbon. Nanoporous biomaterials are also utilized in hemoperfusion for uremic toxin removal. Further miniaturization of artificial kidney system and improvements on uremic toxin adsorption capacity would require high performance nanoporous biomaterials which possess not only higher surface area, controlled pore size, but also designed architecture or structure and surface functional groups. This article reviews on various nanoporous biomaterials used in current artificial kidney systems and several emerging nanoporous biomaterials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1232-1240, 2017.

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.

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

Context. The Extracorporeal Treatments in Poisoning (EXTRIP) workgroup was created to provide evidence and consensus-based recommendations on the use of extracorporeal treatments (ECTRs) in poisoning. Objectives. To perform a systematic review and provide clinical recommendations for ECTR in carbamazepine poisoning. Methods. After a systematic literature search, the subgroup extracted the data and summarized the findings following a pre-determined format. The entire workgroup voted via a two-round modified Delphi method to reach a consensus on voting statements, using a RAND/UCLA Appropriateness Method to quantify disagreement. Anonymous votes were compiled, returned, and discussed in person. A second vote determined the final recommendations. Results. Seventy-four articles met inclusion criteria. Articles included case reports, case series, descriptive cohorts, pharmacokinetic studies, and in-vitro studies; two poor-quality observational studies were identified, yielding a very low quality of evidence for all recommendations. Data on 173 patients, including 6 fatalities, were reviewed. The workgroup concluded that carbamazepine is moderately dialyzable and made the following recommendations: ECTR is suggested in severe carbamazepine poisoning (2D). ECTR is recommended if multiple seizures occur and are refractory to treatment (1D), or if life-threatening dysrhythmias occur (1D). ECTR is suggested if prolonged coma or respiratory depression requiring mechanical ventilation are present (2D) or if significant toxicity persists, particularly when carbamazepine concentrations rise or remain elevated, despite using multiple-dose activated charcoal (MDAC) and supportive measures (2D). ECTR should be continued until clinical improvement is apparent (1D) or the serum carbamazepine concentration is below 10 mg/L (42 the μ in μmol/L looks weird.) (2D). Intermittent hemodialysis is the preferred ECTR (1D), but both intermittent hemoperfusion (1D) or continuous renal replacement therapies (3D) are alternatives if hemodialysis is not available. MDAC therapy should be continued during ECTR (1D). Conclusion. Despite the low quality of the available clinical evidence and the high protein binding capacity of carbamazepine, the workgroup suggested extracorporeal removal in cases of severe carbamazepine poisoning.

Hemoperfusion for the treatment of poisoning: technology, determinants of poison clearance, and application in clinical practice

Hemoperfusion is an extracorporeal treatment based on adsorption, historically reserved for the treatment of acute poisonings. Its use was popularized in the 1970s after several in vitro and animal experiments had demonstrated its efficacy, and was even preferred over hemodialysis in the management of overdosed patients. With the advent of new and more efficient dialytic modalities, hemoperfusion is now less frequently performed in the Western world. However, hemoperfusion still remains popular in developing countries. The present article reviews the technique of hemoperfusion, the factors influencing poison clearance through adsorption and its current applications.

Cryogels: morphological, structural and adsorption characterisation

Experimental results on polymer, protein, and composite cryogels and data treatment methods used for morphological, textural, structural, adsorption and diffusion characterisation of the materials are analysed and compared. Treatment of microscopic images with specific software gives quantitative structural information on both native cryogels and freeze-dried materials that is useful to analyse the drying effects on their structure. A combination of cryoporometry, relaxometry, thermoporometry, small angle X-ray scattering (SAXS), equilibrium and kinetic adsorption of low and high-molecular weight compounds, diffusion breakthrough of macromolecules within macroporous cryogel membranes, studying interactions of cells with cryogels provides a consistent and comprehensive picture of textural, structural and adsorption properties of a variety of cryogels. This analysis allows us to establish certain regularities in the cryogel properties related to narrow (diameter 0.4<d<2 nm), middle (2<d<50 nm) and broad (50<d<100 nm) nanopores, micropores (100 nm<d<100 μm) and macropores (d>100 μm) with boundary sizes within modified life science pore classification. Particular attention is paid to water bound in cryogels in native superhydrated or freeze-dried states. At least, five states of water - free unbound, weakly bound (changes in the Gibbs free energy-ΔG<0.5-0.8 kJ/mol) and strongly bound (-ΔG>0.8 kJ/mol), and weakly associated (chemical shift of the proton resonance δ(H)=1-2 ppm) and strongly associated (δ(H)=3-6 ppm) waters can be distinguished in hydrated cryogels using (1)H NMR, DSC, TSDC, TG and other methods. Different software for image treatment or developed to analyse the data obtained with the adsorption, diffusion, SAXS, cryoporometry and thermoporometry methods and based on regularisation algorithms is analysed and used for the quantitative morphological, structural and adsorption characterisation of individual and composite cryogels, including polymers filled with solid nano- or microparticles.

Activation-dependent adsorption of cytokines and toxins related to liver failure to carbon beads

In the course of severe pathological conditions, such as acute liver failure and sepsis, toxic metabolites and mediators of inflammation are released into the patient's circulation. One option for the supportive treatment of these conditions is plasmapheresis, in which plasma, after being separated from the cellular components of the blood, is cleansed by adsorption of harmful molecules on polymers or activated carbon. In this work, the adsorption characteristics of activated carbon beads with levels of activation ranging from 0 to 86% were assessed for both hydrophobic compounds accumulating in liver failure (bilirubin, cholic acid, phenol and tryptophan) and cytokines (tumor necrosis factor α and interleukin-6). Progressive activation resulted in significant gradual reduction of both bulk density and mean particle size, in an increase in the specific surface area, and to changes in pore size distribution with progressive broadening of micropores. These structural changes went hand in hand with enhanced adsorption of small adsorbates, such as IL-6 and cholic acid and, to a lesser extent, also of large molecules, such as TNF-α.

Study of valproic acid-induced endogenous and exogenous metabolite alterations using LC–MS-based metabolomics

Background: Valproic acid (VPA; an anticonvulsant drug) therapy is associated with hepatotoxicity as well as renal toxicity. An LC–MS-based metabolomics approach was undertaken in order to detect urinary VPA metabolites and to discover early biomarkers of the adverse effects induced by VPA. Results: CD-1 mice were either subcutaneously injected with 600-mg VPA/kg body weight or vehicle only, and urine samples were collected at 6, 12, 24 and 48 h postinjection. A metabolomics approach combined with principal component analysis was utilized to identify VPA-related metabolites and altered endogenous metabolites in urine. Some VPA metabolites indicated potential liver toxicity caused by VPA administration. Additionally, some altered endogenous metabolites suggested that renal function might be perturbed by VPA dosing. Conclusion: LC–MS-based metabolomics is capable of rapidly profiling VPA drug metabolites and is a powerful tool for the discovery of potential early biomarkers related to perturbations in liver and kidney function.

Hemoperfusion in the treatment of acute clozapine intoxication in China

BACKGROUND AND AIMS

No systematic study has focused on the characteristics and outcome of acute clozapine intoxication, although clozapine is the most widely used antipsychotic agent in China. The study reported herein examined the features of clozapine intoxication and the therapeutic effect of hemoperfusion (HP).

METHODS

In a retrospective chart review, the notes of 47 patients who attempted suicide by ingesting large amounts of clozapine and were treated at the only psychiatric emergency service in Beijing were analyzed. Of the 20 unconscious patients with plasma clozapine concentrations of more than 2000 ng/mL, 14 received a combination of HP and symptomatic treatment, whereas the other 6 and the remaining 27 patients received only symptomatic treatment. Patients' psychiatric conditions and both plasma clozapine and norclozapine concentrations were closely monitored and registered.

RESULTS

One patient died of pulmonary edema and subsequent heart failure, but the rest of the patients recovered without any sequelae. Patients who received HP regained consciousness significantly faster than their counterparts with the same level of clozapine plasma concentration (>2000 ng/mL) who did not receive HP.

CONCLUSIONS

A combination of HP and symptomatic treatment is the best therapeutic option when plasma clozapine concentration is high.