Benefit of hemodialysis in carbamazepine intoxications with neurological complications

AIM

It is aimed to share the fact that hemodialysis is also useful in carbamazepine intoxications with prominent neurological side effects in cases hemoperfusion is not available.

PATIENTS AND METHOD

Files of 49 patients presenting our Emergency Room with a prediagnosis of carbamazepine intoxication were analyzed retrospectively. Demographic and laboratory data of patients were recorded on study form. Patients were divided into two groups as those applied hemodialysis (Group 1) and those not applied hemodialysis (Group 2). Group 1 included 13 patients while group 2 did 36.

RESULTS

Statistically significant differences were detected between groups in terms of heart rate, Glasgow Coma scale score, presence of convulsions, midriasis and blood carbamazepine levels at the time of presentation. It was observed that carbamazepine levels decreased by 58% via hemodialysis in those receiving hemodialysis.

DISCUSSION

Hemodialysis is simple, cheap, widespread and easier to apply compared to hemoperfusion. It has been shown that acute carbamazepine intoxication can be treated with low flow-high activity standard hemodialysis and it is a good therapeutic option.

Out with the old, in with the new? Case reports of the clinical features and acute management of two novel designer drugs

Methoxydine (4-MeO-PCP) and Methoxetamine (3-MeO-2-Oxo-PCE) are both commercially produced designer drugs with structural and biochemical similarities to phencyclidine (PCP). Although phencyclidine toxicity is well documented, its recreational use in present times is rare. With the advent of new designer drugs being available widely through internet sites, Acute Physicians should be aware of the clinical features and management of these potential toxins. We present a case of methoxydine ingestion (which to our knowledge has not been previously documented in any medical journals) and a case of methoxetamine ingestion, and discuss their history, contrasting clinical features and acute management.

Neurotoxicity of the CNS: diagnosis, treatment and prevention

Treatment-induced CNS toxicity remains a major cause of morbidity in patients with cancer. Real advances in the design of safer radiation procedures have been counterbalanced by a wider use of combined radiotherapy (RT)-chemotherapy regimens, the development of radiosurgery, and the increasing number of long-term survivors. While classic radionecrosis or chemonecrosis have become less common, more subtle changes such as progressive cognitive dysfunction are increasingly reported after RT (radiation-induced leukoencephalopathy) or chemotherapy (administered alone or in combination). The most important and controversial complications of RT, chemotherapy and combined treatments in the CNS are reviewed here, including new diagnostic tools, practical management and prevention that will influence the future management of cancer patients.

Significant pregabalin toxicity managed with supportive care alone

There are two previously reported cases describing the management of pregabalin self-poisoning and one further case of management of therapeutic pregabalin accumulation. The peak reported pregabalin concentrations in these cases ranged from 13 mg/L to approximately 60 mg/L. Previous case reports have suggested that both supportive care and enhanced elimination are appropriate managements for pregabalin toxicity. A 54-year-old male presented following ingestion of 8.4 g of pregabalin. Initially, he had no clinical features of toxicity, although he developed significant neurological depression and coma approximately 3 h post-ingestion. He was managed with supportive care (including endotracheal intubation and mechanical ventilation) until his level of consciousness improved. Subsequent toxicological screening confirmed isolated pregabalin ingestion, with a serum pregabalin concentration of 66.5 mg/L at the time he clinically deteriorated. The pharmacokinetic properties of pregabalin indicate the potential value of extra-corporeal elimination methods such as haemodialysis. Clinical toxicologists should be aware that whilst there is a pharmacokinetic basis for the use of extra-corporeal methods in those with severe toxicity arising from excessive plasma pregabalin concentrations, there are case reports, including this one, where patients have been managed with supportive measures only.

Cellular and molecular mechanisms of dichlorvos neurotoxicity: cholinergic, nonchlolinergic, cell signaling, gene expression and therapeutic aspects

Inappropriate use of toxic chemicals is common in developing countries, where it leads to excessive exposure and high risks of unintentional poisoning. Risks are particularly high with the pesticides used in agriculture, poor rural populations live and work in close proximity to these compounds and often store these compounds in and around their homes. It is estimated that most of the death from pesticide poisoning occur in developing countries. Organophosphate insecticides have been extensively used in agriculture in developing countries. Dichlorvos is a synthetic insecticide and belongs to a family of chemically related organophosphate pesticides (OP). Toxicity of dichlorvos has been documented in accidental human poisoning, epidemiological studies, and animal models. In this review, molecular mechanisms of dichlorvos neurotoxicity have been described. Usage, biotransformation, environmental levels, general population and occupational exposure, effects on cell signaling receptors, mitochondrial metabolism, oxidative stress and gene expression of dichlorvos have been reviewed. Assessment of acute and chronic exposures as well as neurotoxicity risk for lifetime exposures to dichlorvos have also been considered. In addition special emphasis has been given to describe, the role of dichlorvos in the chronic neurotoxicity and its molecular targets that ultimately lead to neurodegeneration.

[Chemotherapy-induced peripheral neuropathy: an unresolved issue]

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is the most prevalent neurological complication of cancer treatment, affecting a third of all patients who undergo chemotherapy. CIPN impairs functional capacity, compromises the quality of life and results in dose reduction or cessation of chemotherapy, representing a dose-limiting side effect of many antineoplastic drugs. In addition to classic, novel agents, bortezomib and oxaliplatin have been shown to have a significant risk of CIPN.

METHODS

By reviewing literature, this article analyses relevant issues and recent advances regarding the pathogenesis, incidence, risk factors, diagnosis, characteristics and management of CIPN.

RESULTS

Research into the pathophysiology and identification of risk factors for individual patients is growing. A future avenue of investigation includes the identification of patients at lower or higher risk based on their genotype. Best tools for CIPN assessment are not defined. Many agents have been claimed to be neuroprotectors without showing significant results in large randomised clinical trials.

CONCLUSIONS

Early recognition and subsequent dose reduction/discontinuation of the offending agent is the only way to minimise the development of this potentially debilitating complication. Due to the lack of effective prophylactic or symptomatic treatments up to now, neurological monitoring should be recommended in patient candidates to be treated with neurotoxic antineoplastic agents, mainly when they present baseline neuropathy. Development of reliable methods for CIPN assessment is essential.

[The use of cytoflavin in combined neurometabolic therapy of acute cerebral insufficiency associated with acute poisoning with neurotropic poisons]

Examination and treatment of 262 patients with severe acute intoxication by neurotropic poisons and unaffected oxygen delivery system showed that inclusion of cytoflavin in combined neurometabolic therapy of acute cerebral insufficiency significantly reduced severity of metabolic disorders. Specifically, tissue hypoxy, endotoxicosis, lipid peroxidation activity, and immunosuppression decreased while antioxidative protection and clinical picture were improved. Duration of comatose state and artificial lung ventilation was reduced from 64.5 +/- 15.1 to 28.8 +/- 10.2 hours and that of critical condition from 117.2 +/- 17.2 to 63.7 +/- 9.2 hours. Overall lethality dropped from 16 to 9.9%.

[Clinical and cranial MRI analysis on five cases of toxic encephalopathy induced by dichloroethane]

OBJECTIVE

To investigate the clinical features, cranial MRI and treatment of toxic encephalopathy induced by 1, 2-dichloroethane (1, 2-DCE).

METHODS

The clinical, MRI features and treatment of 5 patients with toxic encephalopathy induced by 1,2-DCE were observed and analyzed.

RESULTS

Five patients all presented with subacute onset with a history of direct exposure to 1,2-DCE. Lumbar cerebrospinal fluid pressures were all increased in 5 patients. All 5 patients had obvious intracranial hypertension. Liver and kidney function had no obvious abnormalities; Cranial MRI showed T1WI low signal and T2WI high signal in bilateral hemispheric white matter, cerebellar dentate nucleus and globus pallidus. After the treatment of dehydrating agent, glucocorticoid and supportive treatment, four patients were clearly improved, and one patient had cerebral hernia formation.

CONCLUSION

The main neurological clinical features in patients with 1,2-DEC poisoning is obvious intracranial hypertension. The prognosis is usually good with early and long term use of glucocorticoids and dehydrating agent in poisoning patients.

Valproate-associated hyperammonemic encephalopathy

The use of valproic acid (VPA) (also known as Depakote, Depakene, and others) frequently results in elevated plasma ammonia. In some people, hyperammonemia may be clinically significant, resulting in hyperammonemic encephalopathy, which may be severe. Valproic acid-induced hyperammonemic encephalopathy may occur in people with normal liver function, despite normal doses and serum levels of VPA. We describe 2 cases of valproic acid-induced hyperammonemic encephalopathy in patients with supratherapeutic VPA levels, although the condition has been described in people with normal VPA levels. With the increasing indications and off-label uses of VPA, family physicians should be aware of this potential complication of VPA and check ammonia levels in patients taking VPA who present with alterations in mental status. Treatment with L-carnitine may be beneficial in reducing ammonia levels.

Human embryonic stem cell-derived neural precursor transplants attenuate apomorphine-induced rotational behavior in rats with unilateral quinolinic acid lesions

To test the efficacy of human embryonic stem cell (hESC)-derived neural precursors in an experimental model of Huntington's disease (HD), we differentiated hESC into nestin-positive neural precursors by co-culturing with PA6 stromal cells, and subsequently transplanted them into the striatum of quinolinic acid (QA)-induced HD model. The transplanted animals exhibited a behavioral recovery in the apomorphine-induced rotation test for 3 weeks after transplantation. The transplanted hESC-derived neural precursors were found in both cortex and striatum. They also exhibited some evidence of neuronal differentiation. At the time of examination, no tumor was detected. These results strongly suggest that hESC-derived neural precursors can lead to a behavioral recovery, as well as neuronal differentiation, in the pre-clinical model of HD.

Nonconventional terror--the anesthesiologist's role in a nerve agent event

The structure and biologic action of nerve agents is similar to organophosphates, commonly used as insecticides. Acetylcholine accumulation and binding to the cholinergic receptor site stimulates the affected organs producing a predictable set of clinical symptoms. Treatment of the affected patients will include decontamination, respiratory and hemodynamic support, as well as specific antidotes. The multiple casualties that may be expected present additional logistical and organizational problems. The specific skills of anesthesiologists will make them invaluable members of the care team in such a chemical mass casualty event.

Naja kaouthia: Two cases of Asiatic cobra envenomations

Envenomation from cobra bites causes major morbidity and mortality in Asia and Africa but rarely in the United States. We describe two patients bitten by the Asiatic Cobra (Naja Kaouthia)--both successfully treated in the emergency department. Patient 1 was a 23-year-old woman bitten in the buttock by her cobra. Examination demonstrated two puncture wounds. She developed cranial neuropathy, respiratory failure, and coagulopathy 10 h later, necessitating endotracheal intubation and polyvalent antivenom administration. The patient recovered fully with minimal wound necrosis. Patient 2, a 44-year-old man, was bitten on the hand by his cobra. Examination revealed a puncture wound with progressive swelling. Edrophonium and monovalent antivenom were administered, and he recovered uneventfully. These cases emphasize the varied clinical presentations of the Asiatic cobra. Patient 1 developed delayed neurotoxicity, respiratory failure, and hematotoxicity with minimal wound necrosis, whereas Patient 2 experienced a more typical clinical course.