Is quantitative sensory testing helpful in the management of oxaliplatin neuropathy? a two-year clinical study

PURPOSE

To better understand how quantitative sensory testing could help the clinician in the management of oxaliplatin-induced peripheral neuropathy in terms of earlier and more reliable detection, we conducted a two-year prospective study.

METHODS

Thermal sensory assessment, tactile sensory assessment, neuropathic pain assessment and adverse events gradation (NCI-CTC) were performed during treatment and 6 months after treatment completion.

RESULTS

35 patients were enrolled and followed-up during one year. Cold and Warm Detection Thresholds were higher 6 months after treatment completion than at enrollment. Mechanical detection thresholds didn't change significantly. Neurotoxicity was mostly grade-1, only 18% grade-2 and no grade-3. Grade-2 patients received lower oxaliplatin cumulative dose than grade-1, which reveals effective dose adaptation and grade-2 patients were more likely to develop painful neuropathy.

CONCLUSION

Thermal thresholds impairment emerges too late to help the clinician in the prophylaxis of neuropathy. Management of OXA-treatment based on NCI-CTC, as currently recommended, remains the best way to detect neuropathy and ensure treatment adaptation.

Examining the Impact of a Web-Based Intervention to Promote Patient Activation in Chemotherapy-Induced Peripheral Neuropathy Assessment and Management

Lack of activation in self-care can compromise a patient's ability to monitor and manage cancer treatment-related side effects, such as chemotherapy-induced peripheral neuropathy (CIPN). The web-based Carevive® Care Planning System (CPS) was developed to promote evidence-based symptom assessment and treatment by enhancing patients' involvement in their own care. The purpose of this single-arm, pre-test/post-test, prospective study was to examine whether the CPS can promote patient activation in CIPN symptom assessment and management. Seventy-five women with breast cancer receiving neurotoxic chemotherapy were recruited from a Comprehensive Cancer Center. Using standardized neuropathy measures embedded within the CPS, patients reported their CIPN symptoms over three consecutive clinical visits and completed the Patient Activation Measure (PAM) at the first and third visits. Mean changes in PAM scores between visits were compared using repeated measure analysis of covariance, adjusting for age. At baseline, patients were diagnosed with cancer within the past year (94.7%), highly activated (85% Level III/IV), and had a mean age of 51.3. PAM scores improved significantly from 67.15 (SD = 13.5; range = 47-100) at visit one to 69.29 (SD = 16.18; range = 47-100) (p = 0.02) (n = 62) at visit three. However, patients perceived the CPS to be of minimal value because it solely focused on CIPN and, for many, CIPN was not severe enough to motivate them to seek out symptom management information. Further research is needed to assess the utility of the CPS in promoting activation in the assessment and management of varying cancer treatment-related symptoms.

Chemotherapy-induced peripheral neuropathy: A current review

Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting side effect experienced by patients receiving treatment for cancer. Approximately 30 to 40% of patients treated with neurotoxic chemotherapy will develop CIPN, and there is considerable variability in its severity between patients. It is often sensory-predominant with pain and can lead to long-term morbidity in survivors. The prevalence and burden of CIPN late effects will likely increase as cancer survival rates continue to improve. In this review, we discuss the approach to peripheral neuropathy in patients with cancer and address the clinical phenotypes and pathomechanisms of specific neurotoxic chemotherapeutic agents. Ann Neurol 2017;81:772-781.

Common toxidromes in movement disorder neurology

BACKGROUND

Physicians can come across patients who are exposed to certain prescription drugs or toxins that can result in adverse effects and complications which have high rates of morbidity and mortality.

OBJECTIVE

To summarise the key clinical features and management of the common movement disorder toxidromes relevant to physicians (with an interest in neurology).

METHODS

We searched PUBMED from 1946 to 2016 for papers relating to movement toxidromes and their treatment. The findings from those studies were then summarised and are presented here.

RESULTS

The key features of 6 of the common movement disorder toxidromes and their treatment are tabulated and highlighted. The management of toxidromes with the highest mortality like neuroleptic malignant syndrome and serotonin syndrome are discussed in detail.

CONCLUSION

There are several toxidromes that have the potential to become a serious life-threatening emergency if there is a delay in recognition of key clinical features and instituting the appropriate treatment at the earliest is crucial.

Treatment of cefuroxime-induced neurotoxicity with continuous venovenous haemofiltration

A 61-year-old woman with decreased consciousness, myoclonus, tremors, nystagmus and bradypnoea, due to cefuroxime-induced neurotoxicity, was admitted to the intensive care unit. Continuous venovenous haemofiltration (CVVH) rapidly reduced plasma cefuroxime concentrations and improved neurological manifestations within the next few hours. Retrospective pharmacokinetic assessment showed a total cefuroxime clearance of 166 ml/min during the CVVH.

Altered mental status and end organ damage associated with the use of gacyclidine: a case series

INTRODUCTION

Over the past decade, there has been a sharp increase in the number of newly identified synthetic drugs. These new drugs are often derivatives of previously abused substances but have unpredictable toxicity. One of these drugs is gacyclidine, a derivative of phencyclidine (PCP). Gacyclidine has been studied as a neuroprotective agent in trauma and as a therapy of soman toxicity. There are no previous reports of its use as a drug of abuse.

CASE REPORTS

During a two-month period in the summer of 2013, a series of patients with severe agitation and end-organ injury were identified in an urban academic Emergency Department (ED). A urine drug of abuse screen was performed on all patients, and serum samples were sent for comprehensive toxicology analysis. A total of five patients were identified as having agitation, rhabdomyolysis, and elevated troponin (Table 1). Three of the five patients reported use of methamphetamine, and all five patients had urine drug screens positive for amphetamine. Comprehensive serum analysis identified methamphetamine in three cases, cocaine metabolites in one case, and a potential untargeted match for gacyclidine in all five cases. No other drugs of abuse were identified.

DISCUSSION

This is the first series of cases describing possible gacyclidine intoxication. The possible source of the gacyclidine is unknown but it may have been an adulterant in methamphetamine as all patients who were questioned reported methamphetamine use. These cases highlight the importance of screening for new drugs of abuse when patients present with atypical or severe symptoms. Gacyclidine has the potential to become a drug of abuse both by itself and in conjunction with other agents and toxicity from gacyclidine can be severe. It is the role of the medical toxicology field to identify new agents such as gacyclidine early and to attempt to educate the community on the dangers of these new drugs of abuse.

Acute toxicity associated with the recreational use of the novel dissociative psychoactive substance methoxphenidine

INTRODUCTION

Methoxphenidine is a novel dissociative designer drug of the diarylethylamine class which shares structural features with phencyclidine (PCP), and is not at present subject to restrictive regulations. There is very limited information about the acute toxicity profile of methoxphenidine and the only sources are anonymous internet sites and a 1989 patent of the Searle Company. We report a case of analytically confirmed oral methoxphenidine toxicity.

CASE DETAILS

A 53-year-old man was found on the street in a somnolent and confusional state. Observed signs and symptoms such as tachycardia (112 bpm), hypertension (220/125 mmHg), echolalia, confusion, agitation, opisthotonus, nystagmus and amnesia were consistent with phencyclidine-induced adverse effects. Temperature (99.1°F (37.3°C)) and peripheral oxygen saturation while breathing room air (99%) were normal. Laboratory analysis revealed an increase of creatine kinase (max 865 U/L), alanine aminotransferase (72 U/L) and gamma-glutamyl transpeptidase (123 U/L). Methoxphenidine was identified by a liquid chromatography tandem mass spectrometry toxicological screening method using turbulent flow online extraction in plasma and urine samples collected on admission. The clinical course was favourable and signs and symptoms resolved with symptomatic treatment.

CONCLUSION

Based on this case report and users' web reports, and compatible with the chemical structure, methoxphenidine produces effects similar to those of the arylcyclohexylamines, as PCP.

2-(4-Iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25I-NBOMe): clinical case with unique confirmatory testing

INTRODUCTION

2C designer drugs have been in use since the 1970s, but new drugs continue to develop from substitutions to the base phenethylamine structure. This creates new clinical profiles and difficulty with laboratory confirmation. 2-(4-Iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25I-NBOMe) is a relatively new 2C drug that is more potent than structural 2C analogs; exposure reports are rare. Testing for 2C drugs is developing; specific testing for new analogs such as 25I-NBOMe is a challenge. These drugs do not reliably trigger a positive result on rapid drug immunoassays. Additionally, most facilities with confirmatory testing capabilities will not identify 25I-NBOMe; methods for detecting 25I-NBOMe in biological samples have not been clearly described nor have optimal metabolic targets for detecting 25I-NBOMe ingestion.

CASE REPORT

An 18-year-old female presented following use of 25I-NBOMe. She had an isolated brief seizure, tachycardia, hypertension, agitation, and confusion. She improved with intravenously administered fluids and benzodiazepines and was discharged 7 h postingestion. Urine was analyzed using quantitative LC-MS/MS methodology for 25I-NBOMe, 2-(4-chloro-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)-methyl]ethanamine (25C-NBOMe), and 2-(2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25H-NBOMe). 25I-NBOMe was found at a concentration of 7.5 ng/mL, and 25H-NBOMe was detected as well. Additional testing was pursued to characterize the metabolism of 25I-NBOMe; the sample was reanalyzed with UPLC-time-of-flight mass spectrometry to identify excreted metabolites. The sample was additionally analyzed for the presence of 2,5-dimethoxy-4-iodophenethylamine (2C-I), 4-bromo-2,5-dimethoxyphenethylamine (2C-B), and 1-(2,5-dimethoxy-4-ethylphenyl)-2-aminoethane (2C-E).

DISCUSSION

This is a report of a patient presenting following exposure to 25I-NBOMe, a dangerous member of the evolving 2C drug class. The exposure was confirmed in a unique manner that could prove helpful in guiding further patient analysis and laboratory studies.

Oxidative stress and mitochondrial dysfunction in aluminium neurotoxicity and its amelioration: a review

Aluminium is light weight and toxic metal present ubiquitously on earth which has gained considerable attention due to its neurotoxic effects. The widespread use of products made from or containing aluminium is ensuring its presence in our body. There is prolonged retention of a fraction of aluminium that enters the brain, suggesting its potential for accumulation with repeated exposures. There is no known biological role for aluminium within the body but adverse physiological effects of this metal have been observed in mammals. The generation of oxidative stress may be attributed to its toxic consequences in animals and humans. The oxidative stress has been implicated in pathogenesis of various neurodegenerative conditions including Alzheimer's disease and Parkinson's disease. Though it remains unclear whether oxidative stress is a major cause or merely a consequence of cellular dysfunction associated with neurodegenerative diseases, an accumulating body of evidence implicates that impaired mitochondrial energy production and increased mitochondrial oxidative damage is associated with the pathogenesis of neurodegenerative disorders. Being involved in the production of reactive oxygen species, aluminium may impair mitochondrial bioenergetics and may lead to the generation of oxidative stress. In this review, we have discussed the oxidative stress and mitochondrial dysfunctions occurring in Al neurotoxicity. In addition, the ameliorative measures undertaken in aluminium induced oxidative stress and mitochondrial dysfunctions have also been highlighted.

[Clinical examination of 3 patients with delayed neuropsychiatric encephalopathy induced by carbon monoxide poisoning, who recovered from severe neurocognitive impairment by repetitive hyperbaric oxygen therapy]

We performed hyperbaric oxygen (HBO) therapy for 3 patients with delayed neuropsychiatric encephalopathy induced by carbon monoxide (CO) poisoning. All patients were male and around 50 years old, and they had not received HBO therapy within 24 h after CO poisoning, even though they showed severe consciousness disturbance. In these patients, delayed neuropsychiatric encephalopathy appeared about 25 days after acute CO poisoning, and HBO therapy was initiated within 8 days after disease onset. Although the condition of 2 of the patients worsened initially, they showed significant improvement of neurocognitive impairment after 30 sessions of HBO therapy. The clinical courses of these patients suggest that the effect of HBO therapy can be evaluated after 30 sessions. To evaluate the validity of the indices of the clinical effect of HBO therapy, we performed brain magnetic resonance imaging, single photon emission computed tomography, electroencephalography (EEG), and neurocognitive tests (HDS-R, and Wechsler Adult Intelligence Scale-Revised or III). Our results showed that changes in EEG signals and neurocognitive tests were closely correlated with the patients' clinical courses.

Chemotherapy-induced peripheral neurotoxicity: a critical analysis

With a 3-fold increase in the number of cancer survivors noted since the 1970s, there are now over 28 million cancer survivors worldwide. Accordingly, there is a heightened awareness of long-term toxicities and the impact on quality of life following treatment in cancer survivors. This review will address the increasing importance and challenge of chemotherapy-induced neurotoxicity, with a focus on neuropathy associated with the treatment of breast cancer, colorectal cancer, testicular cancer, and hematological cancers. An overview of the diagnosis, symptomatology, and pathophysiology of chemotherapy-induced peripheral neuropathy will be provided, with a critical analysis of assessment strategies, neuroprotective approaches, and potential treatments. The review will concentrate on neuropathy associated with taxanes, platinum compounds, vinca alkaloids, thalidomide, and bortezomib, providing clinical information specific to these chemotherapies.

[Severe and uncommon complications of anticholinesterase intoxication in children]

BACKGROUND

The Northern region of the Negev desert is an endemic area of organophosphate and carbamate intoxications in Bedouin children. Most victims are intoxicated by drinking the poisonous material kept by the parents in soft drink bottles. Signs and symptoms of intoxication are commonly known and generally include various effects on the central nervous system, usually a decreased level of consciousness in children, cholinergic muscarinic (sweating, rhinorrhea, miosis, vomiting) and nicotinic (weakness) effects. Specific therapy includes Atropine Sulphate and Oximes. PURPOSE AND RESULTS: To describe the course of disease of four (out of 47) children admitted to the Division of Pediatrics with organophosphate or carbamate poisoning during a two-year period. The four children 3-17 years of age ingested the poisonous material: organophosphate chlorpyrifos (2 children); carbamate methomyl (one child) and an unidentified compound in another child. Three of the four patients ingested the poison in a suicide attempt. All 4 children suffered from severe and uncommon complications, including severe respiratory failure from different etiologies. In addition, two of the four suffered from a neurological deficit causing prolonged disability. Three had renal failure necessitating hemofiltration in one case. One child had severe hemodynamic failure and arrhythmias necessitating, among other therapy, the insertion of a temporary pace maker. Two children had (laboratory) pancreatitis. One of the children with severe respiratory failure died after 38 days of extracorporeal membrane oxygenation.

CONCLUSIONS

Intoxications by anticholinesterase compounds are not uncommon among Bedouin children in the Negev. This public health threat should be prevented and completely eradicated by the health authorities. Severe intoxication, especially in cases arising after suicide attempts, wherein the amount of the poisonous material is large, may be complicated by life threatening, multi-organ failure during and after the initial phase of poisoning and may progress into prolonged disability and death.

[Clinical characteristics and treatment of polyneuropathy developed after chemotherapy]

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the main problem of modern cytotoxic therapy. Drug dose reduction, delay or even complete stopping of chemotherapy until the regression of CIPN symptoms impair treatment effectiveness and patients' survival. We studied 44 cancer patients with CIPN developed after polychemotherapy. We suggested a treatment regimen that included a complex of allopathic, homeopathic drugs and hydrotherapy. The treatment resulted in a subjective and objective regression of neuropathy symptoms and improving of quality of life in all patients. Patients who had to delay chemotherapy were able to restart it.

Regenerative effects of umbilical cord matrix cells (UCMCs) in a rodent model of rotenone neurotoxicity

Rotenone is one of the pesticides thought to have neurotoxic effect that could potentially play a role in the development of Parkinson's disease (PD). The neurotoxic effects of rotenone have been used to induce PD model in animals that can help in testing suggested therapies. Cell replacement therapies are suggested as new promising approach for treating PD. This study was done to evaluate the regenerative effect of intrathecal administered umbilical cord matrix cells in a rotenone model of PD in mice. Thirty, male BALB/c mice were used and divided into 3 equal groups. The control group (G.1) received only carboxymethyl cellulose orally once daily at a volume of 10ml/kg. The second group was given a daily rotenone oral dose of 30mg/kg for 28days. The third group received rotenone (30mg/(kgday) orally for 28days) and in the 15th day 1×10(5) of UCMCs were given intrathecally and then they completed the rotenone course. At the 23rd day all the animals were evaluated regarding locomotor incoordination through behavioral tests for monitoring PD development. At the end of the 28days all animals were sacrificed by overdose of phenobarbital and their brain were subjected to immunohistochemical analysis for dopaminergic neurons staining for anti TH antibodies. Intrathecal UCMCs revealed regenerative effects in SNpc as evidenced by immunohistochemical staining; this was in parallel with better performance in behavioral tests. In conclusion, the results of this study revealed the regenerative capacities of UCMCs against rotenone neurotoxicity in mice.

Mechanisms for consideration for intervention in the development of organophosphorus-induced delayed neuropathy

Organophosphorus-induced delayed neuropathy (OPIDN) is a neurodegenerative disorder characterised by ataxia progressing to paralysis with concomitant central and peripheral distal axonopathy. Symptoms of OPIDN in people include tingling of the hands and feet. This tingling is followed by sensory loss, progressive muscle weakness and flaccidity of the distal skeletal muscles of the lower and upper extremities and ataxia, which appear about 8-14 days after exposure. Some organophosphorus compounds (OPs) that are still used in worldwide agriculture have potential to induce OPIDN, including methamidophos, trichlorfon, dichlorvos and chorpyrifos. This review summarizes experimental attempts to prevent and/or treat OPIDN and the different mechanisms involved in each approach. The initial mechanism associated with development of OPIDN is phosphorylation and inhibition of neuropathy target esterase (NTE). The phosphorylated enzyme undergoes a second reaction known as "aging" that results in the loss of one of the "R" groups bound to the phosphorus of the OP. A second mechanism involved in OPIDN is an imbalance in calcium homeostasis. This can lead to the activation of calcium-activated neutral protease and increases in calcium/calmodulin-dependent protein kinases. These events contribute to aberrant phosphorylation of cytoskeletal proteins and protein digestion in the terminal axon that can proceed similarly to Wallerian-type degeneration. Several experimental studies demonstrated alleviation of the signs and symptoms of OPIDN by restoring calcium balance. Other studies have used preadministration of NTE inhibitors, such as carbamates, thiocarbamates, sulfonyl fluorides and phosphinate to prevent OPIDN. Progress is being made, but there is yet no single specific treatment available for use in clinical practice to prevent or alleviate the severe effects of OPIDN.

Anesthetic neurotoxicity

Concerns for toxic effects of anesthesia to the brains of the young and the elderly are mounting. While experimental evidence for such effects in the developing brain is strong, the underlying mechanisms are less well understood and debate continues as to whether young humans are at risk for anesthetic neurotoxicity. The phenomenon of postoperative cognitive deterioration in the elderly remains controversial. Time course, severity, and whether or not it persists long term are under debate. For both patient groups, today's evidence is not sufficient to guide change in clinical practice. Well-designed research is therefore imperative to tackle this critical issue.

Valproate-induced hyperammonemic encephalopathy: a brief review

BACKGROUND

This brief review presents a comprehensive evaluation of valproate-induced encephalopathy (VHE) and also discusses potential mechanisms of the condition.

SCOPE

Sodium valproate (VPA) is an effective antiepileptic drug used in neurology as well as in psychiatry, in adults and children. VHE requires early diagnosis and management. Focused research efforts in understanding the condition will help decrease its incidence. Delay in recognition of VHE can result in the development of potentially life-threatening complications.

FINDINGS

Management options are described. Since VPA frequently causes a modest rise in plasma ammonia levels which is asymptomatic, it is important to recognize the symptoms of VHE promptly and to correlate them with the plasma ammonia levels.

CONCLUSIONS

Although there are several case reports on VHE, this review is a comprehensive evaluation of its causes and potential mechanisms. Rapid diagnosis and management will help in reducing VHE-related morbidity.

Treatment of MDR1 mutant dogs with macrocyclic lactones

P-glycoprotein, encoded by the multidrug resistance gene MDR1, is an ATP-driven drug efflux pump which is highly expressed at the blood-brain barrier of vertebrates. Drug efflux of macrocyclic lactones by P-glycoprotein is highly relevant for the therapeutic safety of macrocyclic lactones, as thereby GABA-gated chloride channels, which are confined to the central nervous system in vertebrates, are protected from high drug concentrations that otherwise would induce neurological toxicity. A 4-bp deletion mutation exists in the MDR1 gene of many dog breeds such as the Collie and the Australian Shepherd, which results in the expression of a non-functional P-glycoprotein and is associated with multiple drug sensitivity. Accordingly, dogs with homozygous MDR1 mutation are in general prone to neurotoxicity by macrocyclic lactones due to their increased brain penetration. Nevertheless, treatment of these dogs with macrocyclic lactones does not inevitably result in neurological symptoms, since, the safety of treatment highly depends on the treatment indication, dosage, route of application, and the individual compound used as outlined in this review. Whereas all available macrocyclic lactones can safely be administered to MDR1 mutant dogs at doses usually used for heartworm prevention, these dogs will experience neurological toxicity following a high dose regimen which is common for mange treatment in dogs. Here, we review and discuss the neurotoxicological potential of different macrocyclic lactones as well as their treatment options in MDR1 mutant dogs.

A novel "molecular tweezer" inhibitor of α-synuclein neurotoxicity in vitro and in vivo

Aggregation of α-synuclein (α-syn) is implicated as being causative in the pathogenesis of Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies. Despite several therapies that improve symptoms in these disorders, none slow disease progression. Recently, a novel "molecular tweezer" (MT) termed CLR01 has been described as a potent inhibitor of assembly and toxicity of multiple amyloidogenic proteins. Here we investigated the ability of CLR01 to inhibit assembly and toxicity of α-syn. In vitro, CLR01 inhibited the assembly of α-syn into β-sheet-rich fibrils and caused disaggregation of pre-formed fibrils, as determined by thioflavin T fluorescence and electron microscopy. α-Syn toxicity was studied in cell cultures and was completely mitigated by CLR01 when α-syn was expressed endogenously or added exogenously. To determine if CLR01 was also protective in vivo, we used a novel zebrafish model of α-syn toxicity (α-syn-ZF), which expresses human, wild-type α-syn in neurons. α-Syn-ZF embryos developed severe deformities due to neuronal apoptosis and most of them died within 48 to 72 h. CLR01 added to the water significantly improved zebrafish phenotype and survival, suppressed α-syn aggregation in neurons, and reduced α-syn-induced apoptosis. α-Syn expression was found to inhibit the ubiquitin proteasome system in α-syn-ZF neurons, resulting in further accumulation of α-syn. Treatment with CLR01 almost completely mitigated the proteasome inhibition. The data suggest that CLR01 is a promising therapeutic agent for the treatment of Parkinson's disease and other synucleinopathies.