Intensive care management of organophosphate insecticide poisoning

Unwashed grapes as a cause of organophosphate poisoning in a child in rural India

This report describes the symptoms of pesticide poisoning in a previously healthy teenage girl. After consuming unwashed grapes for several days, the girl developed the following symptoms: drowsiness, vomiting, truncal weakness and fasciculations in the tongue and hands. Blood tests confirmed exposure to a small amount of the organophosphate (OP) compound, a type of chemical found in certain pesticides. The girl was treated with supportive care and cholinesterase reactivators, which minimised the damage caused by OP poisoning. Within 48 hours, the girl's symptoms improved and she made a full recovery. This case highlights that OP poisoning can present without classic cholinergic crisis symptoms (SLUDGING), including miosis. Fasciculations, as observed in this case, are a significant clue to the diagnosis.

Navigating the Neurological Abyss: A Comprehensive Review of Organophosphate Poisoning Complications

Organophosphate poisoning is a significant global health concern with implications for both occupational and environmental settings. This comprehensive review thoroughly explores the biochemical basis, clinical presentation, diagnostic methods, treatment strategies, and long-term effects of organophosphate exposure. The acute phase is characterized by cholinergic crisis, respiratory distress, and neurological manifestations, while delayed complications include the intermediate syndrome and organophosphate-induced delayed neuropathy. Diagnostic approaches involve clinical evaluation, cholinesterase-level assessments, and imaging studies. Treatment strategies encompass decontamination, antidotes such as atropine and pralidoxime, and supportive care. Long-term effects may include cognitive and neurological sequelae, necessitating rehabilitation approaches such as physical and occupational therapy. Prevention strategies include stringent occupational safety guidelines, sustainable agricultural practices, and public awareness initiatives. The implications for clinical practice underscore the importance of a multidisciplinary approach. At the same time, the call to action emphasizes the need for collaborative efforts in prevention and awareness to mitigate the impact of organophosphate poisoning on public health and the environment.

Atropine sulfate as a continuous intravenous infusion for the treatment of organophosphate toxicity in a cat

Case summary

A 1-year-old male neutered domestic shorthair cat presented on an emergency basis with clinical signs suspected to be secondary to organophosphate (OP) toxicity. The control of clinical abnormalities (bradycardia, obtundation, tachypnea, anorexia) was achieved using high-dose continuous rate intravenous infusion (CRI) of atropine sulfate (maximum rate 0.1 mg/kg/h). After 5 days of hospitalization, the patient made a full clinical recovery without the development of atropine toxicity, intermediate syndrome or delayed polyneuropathy at 4 weeks after discharge.

Relevance and novel information

Treatment of OP toxicity in cats is sparsely reported in veterinary literature. Current standards of treatment and published protocols recommend the use of atropine sulfate as intermittent boluses for the treatment of muscarinic signs of toxicity; however, there is a paucity of information regarding the safety and efficacy of atropine sulfate as a CRI for severe toxicosis as described in humans. This report includes the first published case using such a treatment protocol in a cat.

The lesion site of organophosphorus-induced central apnea and the effects of antidotes

Organophosphorus poisoning kills individuals by causing central apnea; however, the underlying cause of death remains unclear. Following findings that the pre-Bötzinger complex impairment alone does not account for central apnea, we analyzed the effect of paraoxon on the brainstem-spinal cord preparation, spanning the lower medulla oblongata to phrenic nucleus. Respiratory bursts were recorded by connecting electrodes to the ventral 4th cervical nerve root of excised brainstem-spinal cord preparations obtained from 6-day-old Sprague-Dawley rats. We observed changes in respiratory bursts when paraoxon, neostigmine, atropine, and 2-pyridine aldoxime methiodide were administered via bath application. The percentage of burst extinction in the paraoxon-poisoning group was 50% compared with 0% and 18.2% in the atropine and 2-pyridine aldoxime methiodide treatment groups, respectively. Both treatments notably mitigated the paraoxon-induced reduction in respiratory bursts. In the neostigmine group, similar to paraoxon, bursts stopped in 66.7% of cases but were fully reversed by atropine. This indicates that the primary cause of central apnea is muscarinic receptor-mediated in response to acetylcholine excess. Paraoxon-induced central apnea is hypothesized to result from neural abnormalities within the inferior medulla oblongata to the phrenic nucleus, excluding pre-Bötzinger complex. These antidotes antagonize central apnea, suggesting that they may be beneficial therapeutic agents.

Predictors of Mortality in Hospitalized Patients With Pesticide Poisoning

Background Organophosphorus poisoning (OPP) is a prevalent mortality rate that varies from 2% to 25% method of suicides worldwide. ICUs commonly employ various scoring systems such as the Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation II (APACHE II), Simplified Acute Physiology Score II (SAPS II), and International Programme on Chemical Safety (IPCS) Poison Severity Score (PSS) tools for risk stratification for mortality prediction scores and prognosis. This study aims to compare the predictive validity of these systems in hospitalized patients suffering from pesticide poisoning in a teaching hospital located in central India. Methods A prospective study design was utilized to gather relevant variables for calculating the GCS, APACHE II, SAPS II, and IPCS scales in patients affected by pesticide poisoning. Data on the administered doses of atropine and pralidoxime (PAM) were also recorded. Results We have identified several independent predictors of mortality among patients suffering from pesticide poisoning. The GCS (P=0.001), tracheostomy (P=0.001), APACHE II score (P=0.01), and SAPS II score (P=0.001) were all found to be significant indicators of mortality. Interestingly, the GCS demonstrated comparable predictive ability for mortality when compared to the APACHE II (0.82 (95% confidence interval (CI) 0.70 to 0.94)) and SAPS II (0.83 (95% CI 0.72 to 0.94)) scores, with no statistically significant difference (P=0.75) observed. Among the variables used in the IPCS PSS (GCS, heart rate, systolic blood pressure (BP), intubation, and pupil size), only GCS (P=0.05), and intubation (P=0.01) exhibited a significant association with mortality. Conclusions Our study determined that the GCS score, SAPS II, IPCS PSS, and APACHE II exhibited equal efficacy in predicting mortality. Notably, the GCS offered an added advantage due to its simplicity and minimal time requirements compared to the other scales.

Acute organophosphorus toxicity in a regional hospital in Johannesburg, South Africa: A retrospective chart review

Introduction

Intentional and accidental organophosphorus exposures pose a significant healthcare-related burden on South African communities. This study will review the demographics, characteristics and clinical course of patients presenting with features of acute organophosphorus toxicity to a regional Emergency Centre in Johannesburg, South Africa.

Methods

This was a retrospective chart review of all patients treated for possible acute organophosphorus toxicity from January 2020 to August 2021.

Results

A total of 205 patients were identified of which 134 patients were included in the study. The median age was 26 years with a male predominance (male= 56%, female=44%). 109 patients (81.3%) survived, 18 patients (13.4%) demised and the outcome of 7 patients (5.2%) was unknown. The median hospital length of stay was 8 days, (IQR= 5-13 days), and the longest hospital stay was 37 days in ICU. Atropinisation dose was significantly higher for intubated patients (median=140.0mg; IQR=90mg-219.5mg) compared to patients who were not intubated (median=60mg; IQR=20.5mg-120mg, p < 0.05). The length of stay was significantly higher for intubated patients (median=11 days; IQR=7-15 days) compared to patients who were not intubated (median=5 days; IQR=3-8 days, p < 0.00). There was a moderate positive correlation between atropinisation dose and length of stay (Correlation coefficient = 0.37, p < 0.00). There was a moderate negative correlation between atropinisation dose and cholinesterase level (Correlation coefficient= - 0.39, p < 0.00). Of those reported to have adverse effects 78.6%, were related to atropine toxicity.

Conclusion

Our study shows a high mortality rate secondary to organophosphorus toxicity. Significant exposures and thus higher doses of atropine were associated with increased length of stay and need for intubation. We found a high incidence of atropine-related adverse effects. More studies are needed to further establish the balance between the therapeutic and adverse effects of high-dose atropine as a treatment modality for organophosphorus toxicity.

Comparing Sequential Organ Failure Assessment Score, Acute Physiology and Chronic Health Evaluation II, Modified Acute Physiology and Chronic Health Evaluation II, Simplified Acute Physiology Score II and Poisoning Severity Score for Outcome Prediction of Pesticide Poisoned Patients Admitted to the Intensive Care Unit

Objective

This study aimed to assess the severity of poisoning, various scoring systems, including Sequential Organ Failure Assessment (SOFA) score, acute physiology and chronic health evaluation II (APACHE II), Simplified Acute Physiology Score (SAPS II), Modified APACHE II, and poisoning severity score (PSS) were used. In this study, we compared the predictive value of these scoring systems on the outcome of pesticide-poisoned patients.

Methods

This is a cross-sectional study of pesticide-poisoned patients (140 patients) who were admitted to the intensive care unit (ICU) of Khorshid Hospital, Isfahan, Iran, between January 2015 and 2019. The area under the receiver operating characteristic (AUC) curve and the predictive value of scoring systems were compared.

Findings

Poisoning was higher in the male population (72.8%). The causes of poisoning were paraquat, (38.6%), aluminum phosphide, (32.1%), and organophosphate, (29.3%). The mean age of the patients was 33.9 years. Most patients (79.3%) attempted suicide. The mortality rate was 46.43%. The mean of "SOFA score," "APACHE II," "SAPS II," "Modified APACHE II," and "PSS" was 5.9; 15.7; 30.02; 15.8; and 1.9, respectively. There was a significant difference in the mean of all scoring systems for outcome prediction. Among all scoring systems, the SAPS II score with the cutoff point (16.5) had the best criteria for outcome prediction (AUC (0.831 ± 0.037), sensitivity (83.1%, 95% confidence interval [CI]: [71.7-91.2]), specificity (75.7%, 95% CI: [64.3-84.9]), positive predictive values (75.0%, 95% CI: [66.4-82.0]), negative predictive values (83.6%, 95% CI: [74.5-89.9]).

Conclusion

The SAPS II scoring system may be a suitable indicator for outcome predictions in pesticide-poisoned patients in the ICU.

The relationship of serum amylase levels in acute organophosphorus poisoning with its clinical severity and outcome: a cross-sectional study

There are limited literatures studying the pancreatic involvement in organophosphate (OP) poisoning using biochemical means. This study focused on assessing the type of OP poisoning and determining the association of serum amylase levels with the patient's presentation and outcome.

Materials and methods

A cross-sectional study was carried out in the Maharajgunj Medical Campus, Tribhuwan University Teaching Hospital, Kathmandu, Nepal, after ethical approval [Ref: IRB/308 (6-11-E)]. We collected data from 172 participants with OP poisoning over the period of 2 years using nonprobability purposive sampling method. All patients with age group 16-75 years having a history of OP poisoning within the previous 24 h with clinical features and physical evidence of poisoning were included in the study. Those participants with indications of exposure to an entirely different poisons, poisoning with multiple poisons, OP poisoning along with alcohol, chronic alcoholics, comorbid conditions, taking drugs that could affect serum amylase levels (azathioprine, thiazides, furosemide, etc.), and/or treated in other hospitals after poisoning were excluded from the study. Appropriate statistical calculations were made using the statistical package for social sciences (SPSS), version 21. The P-value of less than 0.05 was considered statistically significant.

Results

Metacid (53.5%, 92) was the most common OP poison. There were significantly higher mean values of serum amylase levels either within 12 h of exposure (468.60 vs. 135.4 IU/ml, P<0.001) or after 12 h of exposure (152.0 vs. 58.9 IU/ml, P<0.001) in dead participants than alive ones. The participants with initial and after 12 h of exposure-serum amylase level 100 or more IU/ml had more than two-fold and 18-fold higher odds of severe/life-threatening severity (odds ratio=2.40, 95% CI: 1.28-4.52, P=0.007 and odds ratio=18.67, 95% CI: 8.02-43.47, P<0.001) respectively than those with less than 100 IU/ml.

Conclusions

The clinical severity of OP poisoning is directly related to serum amylase levels. Importantly, higher mean values of serum amylase levels were depicted in those participants with OP poisoning culminating to death. Thus, serum amylase level could be one of the easy measurable prognostic marker of OP poisonings.

Effect of diazinon (organophosphate) on the composition and succession of Calliphoridae assemblages in rabbit carcasses in the Eastern Amazon

Fatal poisonings with diazinon may occur both accidentally or intentionally in suicide cases. Forensic entomotoxicology can aid in understanding these deaths by detecting and analyzing the interference of toxic substances in the biology of necrophagous insects. Hence, this study sought to evaluate diazinon's effect on the composition and succession of calliphorid species in the tropical savannas of the Amazon. Nine rabbit carcasses were divided into three groups: one control and two diazinon treatments (100 mg/kg and 300 mg/kg); each group had three replicates. Three fragments of the Amazon tropical savanna were selected for the experiments. Daily collections of adult and immature calliphorids were performed. Five decomposition stages were observed: fresh, bloated, active decay co-occurring, advanced decay, and dry. Eight species of Calliphoridae were identified among the collected adults: Chloroprocta idioidea (0.1%), Chrysomya albiceps (58.3%), Chrysomya megacephala (14.2%), Chrysomya putoria (2.6%), Cochliomyia hominivorax (1.3%), Cochliomyia macellaria (0.5%), Lucilia eximia (19.8%), and Paralucilia paraensis (3.3%). The adult specimens in the control group with the highest abundance were observed only from the advanced decay stage onward. In the dry stage, abundance was higher in control than in treated carcasses. From the sampled 941 Calliphorid immatures, three species were identified: C. albiceps (76,3%), C. putoria (1%), and L. eximia (22,7). The number of immatures was higher in control than in treated carcasses. Therefore, diazinon interferes with the putrefaction timeframe in carcasses, slowing the decomposition stages and affecting their colonization by immature forms of Calliphoridae.

Trends and Outcomes of Acute Poisoning in Felege Hiwot Comprehensive Specialized Hospital Medical Intensive Care Units: Retrospective Study

Background

Acute poisoning with agrochemicals, medicines and different environmental exposures continues to be a global health problems. However, with our search for reports about acute poisoning, there was no data regarding a change in trends and outcomes of acute poisoning in Ethiopia and its districts.

Objective

This study was to determine the burden of poison-related health hazards, identify poisoning substances, and clinical outcomes of poisoning cases admitted to Felege Hiwot Comprehensive Specialized Hospital- Medical intensive care unit (FHCSH-MICU), Bahir Dar, Ethiopia.

Methods

A retrospective hospital-based study was conducted using patient data archived from March 2019 to February 2020 at FHCSH-MICU. Collected data were analyzed using Statistical Package for Social Sciences (SPSS) software version 26 and descriptive statistics such as measures of central tendency and proportions were computed. The results were reported as text narrations, figures and tables.

Results

A total 121 poisoned patients were identified from the patient registration log books. Among the total FHCSH-MICU cases registered, acute poisoning accounted for 17.0%. Of 121 poison cases, 118 (98.3%) were due to suicide attempts with the female to male ratio being 1.5:1. The majority, 65 (54.0%), of cases were in the range of 21-30 years age. Nearly two-thirds, 75 (62.0%), of the poisoning cases died, accounting for 21.6% of all deaths in the FHCSH-MICU. The most common poisoning substance was aluminum phosphide, 92 (76%).

Conclusion and Recommendations

Aluminum phosphide became the leading poisoning substance in the study area. Nearly two-thirds of the poisoning cases died. Hence, aluminum phosphide must be placed in secured and inaccessible places and it should be replaced by less poisonous rodenticides. Health education and awareness creation about this lethal toxin are strongly advisable.

Succinate prodrugs in combination with atropine and pralidoxime protect cerebral mitochondrial function in a rodent model of acute organophosphate poisoning

Pesticides account for hundreds of millions of cases of acute poisoning worldwide each year, with organophosphates (OPs) being responsible for the majority of all pesticide-related deaths. OPs inhibit the enzyme acetylcholinesterase (AChE), which leads to impairment of the central- and peripheral nervous system. Current standard of care (SOC) alleviates acute neurologic-, cardiovascular- and respiratory symptoms and reduces short term mortality. However, survivors often demonstrate significant neurologic sequelae. This highlights the critical need for further development of adjunctive therapies with novel targets. While the inhibition of AChE is thought to be the main mechanism of injury, mitochondrial dysfunction and resulting metabolic crisis may contribute to the overall toxicity of these agents. We hypothesized that the mitochondrially targeted succinate prodrug NV354 would support mitochondrial function and reduce brain injury during acute intoxication with the OP diisopropylfluorophosphate (DFP). To this end, we developed a rat model of acute DFP intoxication and evaluated the efficacy of NV354 as adjunctive therapy to SOC treatment with atropine and pralidoxime. We demonstrate that NV354, in combination with atropine and pralidoxime therapy, significantly improved cerebral mitochondrial complex IV-linked respiration and reduced signs of brain injury in a rodent model of acute DFP exposure.

Pneumothorax and Pneumomediastinum Complicating Organophosphate Poisoning: A Case Series of Complications Less Understood

Organophosphate compounds are used as insecticides in agricultural and domestic settings throughout the world. Acute organophosphorus (OP) poisoning is a major public health issue. Early diagnosis of OP poisoning and prompt atropinization can save lives. Respiratory failure may occur in patients with OP poisoning for many reasons, including aspiration of gastric contents, excessive secretions, pneumonia, and sepsis complicating acute respiratory distress syndrome. Till date, however, spontaneous pneumothorax and pneumomediastinum have not been reported in cases of OP poisoning. This report presents two similar cases of OP poisoning in which spontaneous pneumothorax and pneumomediastinum developed following OP ingestion.

Effect of Zolpidem Tartrate on the Developmental Rate of Forensically Important Flies Chrysomya megacephala (Diptera: Calliphoridae) and Chrysomya saffranea

Entomotoxicology is an emerging science in the forensic investigation of death; it now influences judicial activities. Briefly, carrion flies ingest various chemicals as they feed on a cadaver. In entomotoxicology, such toxicological compounds are qualitatively and quantitatively analyzed in insects recovered from carrion. Some of these chemicals can disrupt flies' cellular physiology, leading to acceleration or delay in their developmental rate. In this study, the effect of zolpidem-contaminated tissue on the dipteran flies Chrysomya megacephala (Fabricius 1794) and Chrysomya saffranea (Bigot 1877) was assessed. Zolpidem tartrate is a sedative-hypnotic compound commonly used to treat anxiety and sleeping disorders, but it is associated with death from suicide. The effects were tested by providing the flies with liver tissue treated with various concentrations of zolpidem tartrate. The morphological parameters and development rate for all life cycle stages of treated insects were determined and used to estimate postmortem intervals. Results showed that the morphological parameters, i.e., weight, width, and length and rate of development of C. megacephala and C. saffranea was negatively associated with zolpidem tartrate concentration of C. saffranea, were negatively associated with the concentration of zolpidem tartrate, indicating that arthropod evidence evaluation can help establish the cause and time of death.

Case Fatality as an Indicator for the Human Toxicity of Pesticides-A Systematic Scoping Review on the Availability and Variability of Severity Indicators of Pesticide Poisoning

Objective: To investigate if case fatality and other indicators of the severity of human pesticide poisonings can be used to prioritize pesticides of public health concern. To study the heterogeneity of data across countries, cause of poisonings, and treatment facilities. Methods: We searched literature databases as well as the internet for studies on case-fatality and severity scores of pesticide poisoning. Studies published between 1990 and 2014 providing information on active ingredients in pesticides or chemical groups of active ingredients were included. The variability of case-fatality-ratios was analyzed by computing the coefficient of variation as the ratio of the standard deviation to the mean. Findings: A total of 149 papers were identified of which 67 could be included after assessment. Case-fatality-ratio (CFR) on 66 active ingredients and additionally on 13 groups of active ingredients were reported from 20 countries. The overall median CFR for group of pesticides was 9%, for single pesticides 8%. Of those 12 active ingredients with a CFR above 20% more than half are WHO-classified as “moderately hazardous” or “unlikely to present acute hazard”. Two of seven pesticides considered “unlikely to present hazard in normal use” showed a CFR above 20%. The cross-study variability of reported case fatality was rather low. Studies most often utilized the Glasgow Coma Score for grading the severity of poisoning. Conclusion: Although human pesticide poisoning is a serious public health problem, an unexpectedly small number of publications report on the clinical outcomes within our study period. However, CFRs of acute human pesticide poisoning are available for several groups of pesticides as well as for active ingredients showing moderate cross-study variability. Our results underline that CFR is an indicator of the human toxicity of pesticides and can be utilized to prioritize highly hazardous pesticides especially since there is limited correspondence between the animal-test-based hazard classification and the human CFR of the respective pesticide. The reporting of available poisoning data should be improved, human case-fatality data are a reasonable tool to be included systematically in the periodic statutory review of pesticides and their regulation.

Serum amylase as a prognostic marker of organophosphate poisoning

BACKGROUND

Organophosphate (OP) insecticides are important compounds as the most probable common cause of acute poisonings in developing countries. OP intoxication often presents as medical emergencies, and its related morbidity and mortality have not decreased despite major advances in critical care. This study aims to determine the impact of serum amylase level for estimation of prognosis in patients with acute OP poisoning.

METHODS

This observational case-control study was done during two years on 332 consecutive patients with acute OP poisoning. Clinical and demographic data, serum amylase level on early admission time, morbidity, and outcome were determined. Data were analyzed in the form of a frequency distribution table by using SPSS 11.0 version software.

RESULTS

The mean age of patients with acute OP poisoning was 28.9 ± 23.95 with slightly female dominance. All patients were intoxicated via the gastrointestinal route. The mean amylase level of patients with deterioration of mental status, tachycardia, ICU admission, and death was significantly higher.

CONCLUSIONS

Among patients with OP poisoning, higher serum amylase than normal was associated with severe clinical course and increased risk for mortality. Determination of serum amylase can be effective in the quick prediction of the outcome.

Recombinant organophosphorus hydrolase (OPH) expression in E. coli for the effective detection of organophosphate pesticides

Accumulation and exposure of organophosphate pesticides are of great concern today owing to their abundant usage and potential health hazards. Harmful effects of organophosphate pesticide exposure and limitations of the available treatment methods necessitate the development of reliable, selective, cost-effective, and sensitive methods of detection. We developed a novel biosensor based on the enzymatic action of recombinant organophosphorus hydrolase (OPH) expressed in E. coli. We report the development of colorimetric biosensors made of His-Nus-OPH as well as His-Nus-OPH loaded alginate microspheres. The colorimetric detection method developed using solution-phase and alginate-encapsulated His-Nus-OPH exhibited detection limits of 0.045 and 0.039 mM, respectively, for ethyl paraoxon, and 0.101 and 0.049 mM, respectively, for methyl parathion. Additionally, fluorescence measurement using pH-sensitive fluorescein isothiocyanate (FITC) was used to sense the quantity of organophosphorus pesticides. The fluorometric detection method using solution-phase His-Nus-OPH, with ethyl paraoxon and methyl parathion as the substrate, reveals the lower limit of detection as 0.014 mM and 0.044 mM, respectively. Our results demonstrate the viability of His-Nus-OPH for OP detection with good sensitivity, LOD, and linear range. We report the first use of N-terminal His-NusA-tagged OPH, which enhances solubility significantly and presents a significant advance for the scientific community.

Toxicokinetic analysis of commonly used pesticides using data on acute poisoning cases from Hyderabad, South India

Organophosphorus pesticides (OPs) interfere with the activity of acetylcholinesterase (AChE), a vital enzyme that regulates the functioning of the nervous system, resulting in acetylcholine (Ach) accumulation at the synapses and myoneural junctions. It remains unknown whether the commonly used OPs in South India also interfere with the AChE activity and their toxicokinetics in humans remains poorly understood. We collected peripheral blood samples from OP-associated suicide cases (hospitalised) and analysed the pesticide concentration and AChE activity, and the toxicokinetics of six commonly used pesticides. LC-MS/MS was used for the estimation of pesticide concentration. Based on a comparison of six pesticide kinetic profiles and toxicokinetic parameters, we concluded that chlorpyrifos ingestion resulted in the highest concentration of chlopyrifos among the identified pesticides, followed by acephate, triazophos, propanil, while dimethoate exhibited the lowest concentration. Based on a time-course analysis, we observed a faster elimination phase for monocrotophos and dimethoate. We observed that there was a significant decrease in the mean concentration of monocrotophos (64 ng/mL) (P = 0.015), while the mean value of AChE (1.08 unit/mL) increased over time. While monocrotophos and dimethoate elimination phases were remarkable in human subjects, the other pesticides did notdemonstrate similar elimination phases owing to their low rate of metabolism and high stability.

A retrospective comparison of the burden of organophosphate poisoning to an Intensive Care Unit in Soweto over two separate periods

Introduction

Organophosphate poisoning (OPP) is a major health-care burden in South Africa. Recently, we have observed that patients admitted to our Intensive Care Unit (ICU) with OPP have followed a more complicated course in comparison to previous years.

Objectives

To describe the differences in the clinical course and costs of patients with OPP between two time periods, namely 2012 and 2017.

Methods

Retrospective comparison of patients admitted to the Intensive Care Unit (ICU) of Chris Hani Baragwanath Academic Hospital between January 2012 to December 2012 and January 2017 to December 2017.

Results

Forty-one patients were found in the database. Patients from our 2017 cohort showed a significantly longer total median (IQR) length of stay 8 (4–17) days vs. 2 (2–3) days, p = 0.000, duration of antidote therapy 5 (3−10) days vs. 2 (2–3) days, p = 0.004 and duration of ventilation 4 (2−11) days vs 1 (1–2) day, p = 0.003. Patients presenting in 2017 were more likely to be admitted to ICU, odds ratio 5.6 (CI 1.2–26). There was a 31- fold increase in ICU costs between 2012 and 2017.

Conclusion

Based on our experience, the clinical course of OPP requiring ICU admission has evolved into a condition with a longer length of stay, duration of antidote therapy, ventilatory support, increased risk of complications and additional costs.

Clinical profile and outcome of acute organophosphate poisoning in children of Upper Egypt: a cross-sectional study

Background

Organophosphates are one of the most common agents of poisoning in developing countries including Egypt. Due to lack of data about characteristics of organophosphates poisoning in our localities, we aimed to evaluate its clinical pattern and factors affecting outcome.

Methods

It was a cross-sectional study conducted in South valley University hospital between January 2019 and December 2019. It included all children ≤16 years of age presented with organophosphates poisoning. Diagnosis was performed from the history taken from the patient’s relatives and presenting symptoms. Demographic data, mode and route of poisoning, time from exposure to presentation, clinical symptomatology, grading and routine investigations were evaluated in addition to treatment taken and outcome.

Results

During the study period, 108 children; mean age was 7.95 ± 4.11 years (range 1. 5-16 years) presented with organophosphorous poisoning. Sixty five (60%) cases were females and 43 (40%) were males. Unintentional acts (87%) were detected more than suicidal (13%) and inhalation route (63.8%) more than ingestion (36. 2%). Miosis was the most frequent clinical sign (100%) followed by respiratory distress (77.7%). Regarding time of presentation to emergency department, 43 (40%) cases were presented within 6 h while others presented more than 6 h post-exposure. Mechanical ventilation (MV) was needed for 14 (13%) cases and 6 (5.5%) cases died due to respiratory failure. Duration of hospital stay, mean time interval from toxic exposure to hospital presentation, leucocytosis, need for MV and cumulative dose of pralidoxime were significantly higher in non survivors than survivors while Pao2 (partial arterial oxygen) and GCS (Glasgow coma scale) were significantly lower.

Conclusion

This study concluded that time consumed till presentation to hospital, low GCS, need for MV, leucocytosis, decreased PaO2 and increased cumulative dose of pralidoxime were independent risk factors of mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02563-w.

The effect of ethion on erythrocyte deformability

Organophosphates cause increased oxidative susceptibility of erythrocytes and changes in erythrocyte deformability ability. We aim is to investigate the role of ethion (ETH) on erythrocyte deformability and to show whether vinpocetine (VIN) and carnosine (CAR) are protective against these changes. The study was performed on Sprague Dawley rats with an average weight of 220 ± 40 g and 4-5 months old. Six experimental groups were composed of 10 rats per group. Hematological parameters, erythrocyte deformability, % hemolysis, 2.3bisphosphoglycerate, and methemoglobin values were measured in blood samples taken after 10 days of drug application. Erythrocyte count, hemoglobin amount, hematocrit value, serum potassium level, and erythrocyte deformability decreased in the ETH group. Leukocyte, platelet count, methemoglobin amount, and % hemolysis rates increased in the ETH group. The values of the ETH + CAR and ETH + VIN groups were found to be closer to the control group. In organophosphate poisoning such as ETH, the deformability ability of erythrocytes exposed to constant oxidative stress is changing, and therefore their ability to deliver oxygen to tissues is negatively affected. VIN and CAR may have improve on erythrocyte deformability in this type of intoxication.

Factors associated with time to successful weaning in mechanically ventilated organophosphate poisoned patients

We designed this study to identify the factors associated with time to successful weaning in mechanically ventilated organophosphate (OP)-poisoned patients as the primary outcomes while duration of mechanical ventilation (MV) support, intensive care unit (ICU), and hospital length of stay (LOS) and in-hospital mortality as the secondary outcomes. We conducted a retrospective study of mechanically ventilated OP-poisoned patients admitted to the ICU of Poison Control Center of Ain Shams, Cairo, Egypt, starting from January 2019 to December 2019. Weaning was considered successful if the patient succeeded in the first spontaneous breathing trial of weaning and did not need reinstitution of MV. We used Cox proportional hazards regression models to identify factors associated with time to successful weaning in the studied patients. A total of 55 patients were enrolled in the study. Thirty-eight patients were weaned successfully. Lower initial red cell distribution width (RDW) levels [adjusted hazard ratio (HR), 0.299, 95% confidence interval (CI) (0.184-0.486)] and lower initial doses of atropine [adjusted HR, 0.97, 95% CI (0.935-0.999)] were independently associated with shorter time to achieve successful weaning. Successfully weaned patients had significantly longer hospital LOS (p = 0.019) and no reported in-hospital mortality (p < 0.001) compared with patients who failed to wean. We concluded that initial RDW and initial doses of atropine were found to be the strongest factors associated with time to successful weaning in mechanically ventilated OP-poisoned patients. RDW and atropine can be used as simple risk assessment tools in OP poisoning.

Biochemical, hematological and immunological parameters and relationship with occupational exposure to pesticides and metals

This study aimed to evaluate biomarkers of exposure to cholinesterase inhibitors insecticides (AChE and BuChE activities) and metals (As, Cd, Cr, Mn, Ni, and Pb blood levels) and their associations with biochemical, hematological, and immunological parameters in farmers from Southern Brazil. One hundred and sixteen individuals were divided into two groups: 62 farmers (exposed group) and 54 subjects non-occupationally exposed (NOE) to agrochemicals. Erythrocyte (AChE) and serum (BuChE) cholinesterases activities were significantly reduced as well as blood Cd and Pb levels were increased in farmers when compared to NOE group (p < 0.05). Farmers presented increased glucose and urea levels compared to NOE group, which were inversely associated with AChE and positively correlated with Cd (p < 0.05), respectively. In addition, Cd was inversely associated with the hematological cells counts, which were significantly reduced in farmers (p < 0.05). C3 complement was higher in farmers and was positively associated with blood Pb (p < 0.05). Surface protein expression analysis revealed a downregulation of LFA-1 and ICAM-1 in farmers. Inverse associations were found between LFA-1 and blood As, Cr, and Ni levels (p < 0.05). Taken together, our results pointed to a relationship between agrochemicals and metals exposure and biochemical, hematological, and immunological disorders that can lead to several chronic conditions.

Clinical Characteristics of Pesticide Self-Harm as Associated with Suicide Attempt Repetition Status

PURPOSE

Previous suicide behavior predicts future suicide risk. Studies of suicide repetition are important for suicide prevention. This study examined the clinical characteristics and psychiatric comorbidities of pesticide self-harm as associated with suicide attempt repetition status.

PATIENTS AND METHODS

This retrospective, observational study included patients admitted to a medical center in northern Taiwan between 2000 and 2015 following suicide attempts by pesticide. Diagnoses were made by a consultation-liaison psychiatry team based on the DSM IV-TR criteria. Independent samples t-test was used to analyze the quantitative variables and Pearson's Chi-squared test with a Bonferroni adjustment for categorical variables. Univariate binary logistic regression analysis was conducted to determine the predictors for repeated suicide attempt and multivariate binary logistic regression analysis to identify significant associated factors.

RESULTS

Among 151 patients, organophosphate pesticides were the most used (80.8%). The average age was 52.9±17.2 years. Most patients were married males from rural areas, with depressive disorder most often diagnosed (40.4%). Nearly one-third of them were suicide repeaters (n=43, 28.5%); these patients were less likely to be married (53.5%, p=0.001), had previously used psychiatric services (72.1%, p<0.001) and chose complex suicide (46.5%, p=0.014) more often compared to nonrepeaters. No significant differences were found between repeaters and nonrepeaters regarding psychiatric comorbidities. Multivariate logistic regression analysis revealed that marital status (odds ratio: 2.916, 95% confidence interval: 1.234-6.891, p=0.015) and previous psychiatric services usage (odds ratio: 6.897, 95% confidence interval: 3.012-15.625, p<0.001) were significant risk factors associated with suicide repetition.

CONCLUSION

Pesticide suicide repeaters were characterized by less likely to be married and more likely to use psychiatric services before suicide attempts. These features help ensuring that the needs of people who have made a suicide attempt are addressed, and it reduces the likelihood of repetition.

Organophosphate poisoning at Chris Hani Baragwanath Academic Hospital 2012 - 2015

Background

Patients with acute organophosphate poisoning are frequently admitted to the Chris Hani Baragwanath Academic Hospital (CHBAH), and yet there is little literature assessing aspects of these admissions.

Objectives

To determine the demographic profile, common clinical and biochemical findings, use of prognostic tools (APACHE II), management and outcome of adult patients admitted to the high care area (HCA) and intensive care unit (ICU) at CHBAH.

Methods

A retrospective data analysis of hospital records for 129 patients admitted to the HCA and ICU at CHBAH for the period 2012 - 2015 was undertaken. The demographic profiles and clinical and biochemical presentations of the patients were determined, together with their subsequent management and outcomes. Use of the APACHE II score as a prognostic tool was evaluated, and the average enzyme inhibition levels demonstrated by the patients was assessed.

Results

The median age of the group was 30 years, with 68.2% being male. The most common clinical finding was pinpoint pupils (96.1%) followed by a Glasgow Coma Score <13 (85.3%), fasciculations (60.5%), diarrhoea (37.2%) and seizures (10.1%). Admissions to the HCA (52.7%) predominated, with the majority of patients requiring ventilator support (99.2%). The mean (SD) duration of stay was 6.8 days for ICU (6.4) and 3.7 days for HCA (5.2). The overall mortality rate was 5.4%. Standard treatment was intravenous atropine. Blood results reflected low levels of acetylcholinesterase enzyme activity. The APACHE II score was underutilised.

Conclusion

The findings of the study underscore the frequent use of organophosphate compounds in our area. Further studies across the country will help to highlight the magnitude of the consequences of organophosphate poisoning, as well as the burden imposed on limited healthcare resources.

Clinical manifestations, laboratory findings, treatment and outcome of acute organophosphate or carbamate intoxication in 102 dogs: A retrospective study

Organophosphates (OP) and carbamates are commonly used insecticides and important intoxication sources of humans and animals. Nevertheless, large scale studies of these intoxications in dogs are unavailable. The medical records of dogs presented to a veterinary hospital were reviewed retrospectively. The study included 102 dogs definitely diagnosed with acute OP or carbamate intoxication. The most common presenting clinical signs included muscle tremor, hypersalivation, miosis, weakness, vomiting and diarrhea. Hypersalivation, muscle tremor and tachypnea were significantly (P < 0.05) associated with survival to discharge; while weakness, mental dullness, anorexia, pale mucous membranes and paddling were significantly associated with death. Common laboratory abnormalities included decreased butyrylcholine esterase activity, acidemia, increased total plasma protein, leukocytosis, hypochloridemia, hyperbilirubinemia, increased creatinine and alanine transaminase (ALT), aspartate transaminase (AST) and creatine kinase activities, and prolonged activated partial thromboplastin time (aPTT). Compared to the survivors, the non-survivors showed significantly: higher frequencies of thrombocytopenia, hypocarbemia, prolonged prothrombin time (PT), hypernatremia, hyperkalemia, hypocholesterolemia, hypoproteinemia, hypertriglyceridemia, increased ALT activity and increased urea concentration; lower median concentrations of venous blood bicarbonate, serum chloride and total CO₂; and higher medians of PT, serum total bilirubin and urea concentrations, and ALT and AST activities. Intoxicated dogs were commonly treated with diphenhydramine, atropine-sulfate, antibiotics, diazepam and pralidoxime, while some (19.2%) required general anesthesia and mechanical ventilation. The survival rate of dogs treated by gastric lavage was higher (P = 0.041) compared to that of the remaining dogs. Development of respiratory failure and mechanical ventilation requirement were significantly associated (P < 0.001) with death. The mortality rate was 17%.

Fatal cases associated with eating chapatti contaminated with organophosphate in Tororo District, Eastern Uganda, 2015: case series

BACKGROUND

Few cases of organophosphate poisoning in developing countries have been investigated using clinical and epidemiological methods. On 30 October 2015, 3 students at Mukuju School, Tororo District, Uganda, died soon after eating chapatti (locally-made flat bread) from the same food stand. Ministry of Health investigated to identify the cause and recommend prevention measures.

METHODS

We defined a case as onset during 30-31 October 2015 in a resident of Mukuju Town of ≥1 of the following symptoms: excessive saliva, profuse sweating, dizziness, low blood pressure, constricted pupils or loss of consciousness. We reviewed medical/police records and interviewed survivors, healthcare workers, and police officers. We collected samples of implicated food for toxicological analysis. Autopsies were performed on decedents to identify the cause of death.

RESULTS

We identified 7 cases with 3 deaths (case-fatality ratio = 43%). Clinical manifestations included acute onset of confusion (100%), constricted pupils (43%), excessive saliva (43%), and low blood pressure (43%). All 7 cases had onset from 16:00-18:00 h on 30 October, with a point-source exposure pattern. Of the 7 cases, 86% (6/7) were men; the mean age was 24 (range: 20-32) years. The 3 decedents each ate a whole chapatti while the other 4 cases ate half or less. Autopsy findings of the 3 decedents indicated organophosphate poisoning. Toxicological analysis found high levels of malathion in leftover foods (266 mg/L in dough and 258 mg/L in chapatti) and malaoxon (a highly toxic malathion derivative) in decedents' postmortem specimens (mean levels of 19 mg/L in the blood and 22 mg/L in the gastric contents). There was a delay of 4 h before the patients received appropriate treatment. Police investigations revealed that flour used to make the chapatti was intentionally contaminated with an organophosphate pesticide.

CONCLUSION

This fatal outbreak of organophosphate poisoning was associated with consumption of roadside-vended chapatti made of flour contaminated with pesticide. Clinicians should be aware of symptoms of organophosphate poisoning and prepared to treat it quickly. Street vendors should carefully consider the source of their ingredients. An in-depth surveillance review of such poisonings in Uganda would guide policymakers in reducing access by criminals and accidental exposures for the public.

Current approaches to enhancing oxime reactivator delivery into the brain

The misuse of organophosphate compounds still represents a current threat worldwide. Treatment of poisoning with organophosphates (OPs) remains unsatisfactorily resolved despite the extensive investment in research in academia. There are no universal, effective and centrally-active acetylcholinesterase (AChE) reactivators to countermeasure OP intoxication. One major obstacle is to overcome the blood-brain barrier (BBB). The central compartment is readily accessible by the OPs which are lipophilic bullets that can easily cross the BBB, whereas first-line therapeutics, namely oxime-based AChE reactivators and atropine, do not cross or do so rather slowly. The limitation of oxime-based AChE reactivators can be ascribed to their chemical nature, bearing a positive charge which is essential either for their AChE affinity or their reactivating potency. The aim of this article is to review the methods for targeting the brain by oxime reactivators that have been developed so far. Approaches using prodrugs, lipophilicity enhancement, or sugar-based oximes have been rather unsuccessful. However, other strategies have been more promising, such as the use of nanoparticles or co-administration of the reactivator with efflux transporter inhibitors. Encouraging results have also been associated with intranasal delivery, but research in this field is still at the beginning. Further research of auspicious approaches is inevitable.

DARK Classics in Chemical Neuroscience: Atropine, Scopolamine, and Other Anticholinergic Deliriant Hallucinogens

Anticholinergic drugs based on tropane alkaloids, including atropine, scopolamine, and hyoscyamine, have been used for various medicinal and toxic purposes for millennia. These drugs are competitive antagonists of acetylcholine muscarinic (M-) receptors that potently modulate the central nervous system (CNS). Currently used clinically to treat vomiting, nausea, and bradycardia, as well as alongside other anesthetics to avoid vagal inhibition, these drugs also evoke potent psychotropic effects, including characteristic delirium-like states with hallucinations, altered mood, and cognitive deficits. Given the growing clinical importance of anti-M deliriant hallucinogens, here we discuss their use and abuse, clinical importance, and the growing value in preclinical (experimental) animal models relevant to modeling CNS functions and dysfunctions.

Oxime K203: a drug candidate for the treatment of tabun intoxication

For over 60 years, researchers across the world have sought to deal with poisoning by nerve agents, the most toxic and lethal chemical weapons. To date, there is no efficient causal antidote with sufficient effect. Every trialed compound fails to fulfil one or more criteria (e.g. reactivation potency, broad reactivation profile). In this recent contribution, we focused our attention to one of the promising compounds, namely the bis-pyridinium reactivator K203. The oxime K203 is very often cited as the best reactivator against tabun poisoning. Herein, we provide all the available literature data in comprehensive and critical review to address whether K203 could be considered as a new drug candidate against organophosphorus poisoning with the stress on tabun. We describe its development from the historical point of view and review all available in vitro as well as in vivo data to date. K203 is easily accessible by a relatively simple two-step synthesis. It is well accommodated in the enzyme active gorge of acetylcholinesterase providing suitable interactions for reactivation, as shown by molecular docking simulations. According to a literature survey, in vitro data for tabun-inhibited AChE are extraordinary. However, in vivo efficiency remains unconvincing. The K203 toxicity profile did not show any perturbations compared to clinically used standards; on the other hand versatility of K203 does not exceed currently available oximes. In summary, K203 does not seem to address current issues associated with the organophosphorus poisoning, especially the broad profile against all nerve agents. However, its reviewed efficacy entitles K203 to be considered as a backup or tentative replacement for obidoxime and trimedoxime, currently only available anti-tabun drugs.

Therapeutic Effect of Adding Magnesium Sulfate in Treatment of Organophosphorus Poisoning

BACKGROUND:

In recent years, the prevalence of poisoning has increased dramatically due to population growth and access to drugs and toxins. Today poisoning is one of the important reasons for visiting hospitals.

AIM:

The present study aimed to investigate the effect of magnesium sulfate on organophosphorous toxicity.

METHODS:

Patients who had inclusion criteria in the study were randomly assigned to one of two groups (control group or case group) by an emergency medicine specialist. Patients’ data including age, sex, ECG, vital signs, arterial oxygen saturation were recorded for patients. Patients in the case group (40 subjects) received 2 mg magnesium sulfate 50%, while the control group (40 subjects) received 100 cc normal saline (as placebo) as an intravenous infusion

RESULTS:

The distribution of gender in the two groups of patients was the same. Also, the mean age, Stature and weight of patients were similar in both groups. In the group receiving magnesium sulfate, diastolic blood pressure was lower when compared with another group, at 0 and 2 hours after intervention. Moreover, the mean of systolic blood pressure in both groups was determined to be the same at all hours. Furthermore, the heart rate in the group receiving sulfate was lower as compared to the control group for 8 hours, 16 and 24 hours after intervention.

CONCLUSION:

The use of magnesium sulfate in organophosphate poisoning reduces therapeutic costs an average hospital length of stay and mortality compared to those who did not receive magnesium sulfate.

One-year mortality among hospital survivors of cholinesterase inhibitor poisoning based on Taiwan National Health Insurance Research Database from 2003 to 2012

Background

Acute cholinesterase inhibitor (CI) poisoning, including organophosphate and carbamate poisoning, is a crucial problem in developing countries. Acute intoxication results in a cholinergic crisis, neurological symptoms, or respiratory failure. However, the short-term and long-term outcomes of CI poisoning are seldom reported.

Methods

Data from the National Health Insurance Research Database were used to investigate the outcomes after organophosphate and carbamate poisoning. Patients who were hospitalized for a first episode of acute CI poisoning between 2003 and 2012 were enrolled in this study. Outcomes of acute CI poisoning with or without mechanical ventilation were analyzed.

Results

Among 6832 patients with CI poisoning, 2010 developed respiratory failure requiring mechanical ventilation, and the other 4822 patients did not require mechanical ventilation. The hospital mortality rate was higher in patients requiring mechanical ventilation than in those not requiring mechanical ventilation (33.3% versus 4.7%, p < 0.0001). In patients with respiratory failure with mechanical ventilation, the patients without pneumonia had higher mortality rate than those with pneumonia. (36.0% versus 19.9%, p < 0.0001). The 1-year mortality rate the survivors of CI poisoning was 6.7%. Among 5932 survivors after cholinesterase inhibitor poisoning, the one-year mortality rate in patients with mechanical ventilation during hospitalization was higher than those without mechanical ventilation during hospitalization (11.4% versus 5.4% respectively, p < 0.0001).

Conclusions

The one-year mortality rate of survivors after CI poisoning was 6.7%. Meanwhile, age, pneumonia, and mechanical ventilation may be predictive factors for the one-year mortality among the survivors after CI poisoning. Diabetes mellitus was not a risk factor for hospital mortality in patients with CI poisoning.

Complex View on Poisoning with Nerve Agents and Organophosphates

OP/nerve agents are still considered as important chemicals acting on living organisms and widely used in human practice. Nerve agents are the most lethal chemical warfare agents. They are characterized according to their action as compounds influencing cholinergic nerve transmission via inhibition of AChE. The symptoms of intoxication comprise nicotinic, muscarinic and central symptoms, for some OP/nerve agents, a delayed neurotoxicity is observed. Cholinesterases (AChE and BuChE) are characterized as the main enzymes involved in the toxic effect of these compounds including their molecular forms. The activity of both enzymes (and molecular forms) is influenced by inhibitors and other factors such as pathological states. There are different methods for cholinesterase determination, however, the most frequent is the method based on the hydrolysis of thiocholine esters and following detection of free SH-group of the released thiocholine. The diagnosis of OP/nerve agents poisoning is based on anamnesis, the clinical status of the intoxicated organism and on cholinesterase determination in the blood. Some principles of prophylaxis against OP/nerve agents poisoning comprising the administration of reversible cholinesterase inhibitors such as pyridostigmine (alone or in combination with other drugs), scavengers such as preparations of cholinesterases, some therapeutic drugs and possible combinations are given. Basic principles of the treatment of nerve agents/OP poisoning are described. New drugs for the treatment are under experimental study based on new approaches to the mechanism of action.

Superior efficacy of HI-6 dimethanesulfonate over pralidoxime methylsulfate against Russian VX poisoning in cynomolgus monkeys (Macaca fascicularis)

Organophosphorus nerve agents still represent a serious risk to human health. In the French armed forces, the current emergency treatment against OP intoxications is a fully licensed wet-dry dual-chambered autoinjector (Ineurope ®), that contains pralidoxime methylsulfate (2-PAM) to reactivate inhibited acetylcholinesterase (AChE), atropine sulfate (AS) and avizafone chlorhydrate (AVZ). While this treatment is effective against several of the known nerve agents, it shows little efficacy against the Russian VX (VR), one of the most toxic compounds. HI-6 dimethanesulfonate (HI-6 DMS) is an oxime able to reactivate in vitro and in vivo VR-inhibited AChE. To confirm the superiority of HI-6 DMS towards 2-PAM prior to licensing, we compared the two 3-drug-combinations (HI-6 vs 2-PAM, 33 and 18 mg/kg respectively, equimolar doses; AS/AVZ 0.25/0.175 mg/kg respectively) in VR-poisoned cynomolgus macaques, the model required by the French drug regulatory agency. In parallel we performed HI-6 pharmacokinetics analysis using a one compartment model. A better efficacy of the HI-6 DMS combination was clearly observed: up to 5 LD₅₀ of VR (i.m.), a single administration of the HI-6 DMS combination, shortly after the onset of clinical signs, prevented death of the four intoxicated animals. Conversely 2-PAM only prevented death in one out of three subjects exposed to the same amount of VR. As expected with V agents, reinhibition of blood AChE was observed but without any apparent impact on the clinical recovery of the animals. A single administration of the HI-6 DMS combination was still but partially effective at 15 LD₅₀ of VR, allowing a 50% survival rate.

High Dose of Pralidoxime Reverses Paraoxon-Induced Respiratory Toxicity in Mice

Objective

The efficiency of pralidoxime in the treatment of human organophosphates poisoning is still unclear. In a rat model, we showed that pralidoxime induced a complete but concentration-dependent reversal of paraoxon-induced respiratory toxicity. The aim of this study was to assess the efficiency of pralidoxime in a species other than rats.

Methods

A dose of diethylparaoxon corresponding to 50% of the median lethal dose was administered subcutaneously to male F1B6D2 mice. Ascending single pralidoxime doses of 10, 50-100 and 150 mg kg^-1 were administered intramuscularly 30 min after diethylparaoxon administration. Ventilation at rest was assessed using whole-body plethysmography and mice temperature was assessed using infrared telemetry. Results are expressed as mean±SE. Statistical analysis used non-parametric tests.

Results

From 30 to 150 min post-injection, diethylparaoxon induced clinical symptoms and a decrease in respiratory frequency, which resulted from an increase in expiratory and inspiratory times associated with an increase in the tidal volume. In the 10-, 50- and 100-mg kg^-1 pralidoxime groups, there was a trend towards a non-significant improvement of paraoxon-induced respiratory toxicity. The 150 mg kg^-1 dose of pralidoxime induced a significant reversal of all respiratory parameters.

Conclusion

In the present study, a toxic but non-lethal model of diethylparaoxon in awake, unrestrained mice was observed. By administering an equipotent dose of diethylparaoxon to rats, a 150 mg kg^-1 dose of pralidoxime administered alone completely reversed diethylparaoxon-induced respiratory toxicity in mice. The dose dependency of reversal suggests that further studies are needed for assessing plasma concentrations of pralidoxime resulting in reversal of toxicity.

Acute Pesticide Poisoning in Children: Hospital Review in Selected Hospitals of Tanzania

BACKGROUND

Acute pesticide poisoning (APP) is a serious problem worldwide. Because the burden of childhood APP is unknown in Tanzania, this study describes the distribution, circumstances, and patterns of APP involving children under 18 years in Tanzania.

METHODOLOGY

A 12-month prospective study was conducted in 10 Tanzanian healthcare facilities in 2006 using a data collection tool for surveillance.

RESULTS

Of 53 childhood poisoning cases identified, 56.6% were female. The most common poisoning circumstances were accidents (49.1%) and suicide (30.2%). The most vulnerable children were 16-17 years old (30.2%). Suicide was significantly more common in females (PRR females/males = 1.66; 95% CI = 1.03-2.68) and accidental cases were more common in children aged 10 years or younger. Suicide was concentrated in children over 10 years, comprising 53% of cases in this age group. Organophosphates (OPs), zinc phosphide, and endosulfan were common amongst reported poisoning agents. The annual APP incidence rate was 1.61/100,000.

CONCLUSION

APP is common among children in this region of Tanzania. Prevention of suicide in older children should address mental health issues and control access to toxic pesticides. Prevention of accidents in younger children requires safer storage and hygiene measures. Diverse interventions are needed to reduce pesticide poisoning among children in Tanzania.

Respiratory Failure Following Organophosphate Poisoning: A Literature Review

Organophosphates (OPs) account for a large portion of suicides globally. OP manifests as cholinergic crises, which underlie respiratory failure. There are many pathways by which respiration is inhibited secondary to organophosphate poisoning. These include central as well as peripheral mechanisms, with central mechanisms predominating. We conducted a literature review in June 2017. PubMed, Embase, and Google Scholar were searched for studies that reported acute organophosphate poisoning in humans. In our review, data were collected from studies published during the years 2001 to 2016. The data consisted of 1,996 patients with organophosphate poisoning, of which 491 (24.6%) required ventilatory support secondary to respiratory failure. Treatment offered to OP poisoning patients should focus on its pathophysiology to benefit from the future outcomes. Recent advances direct the need for a central nervous system (CNS) protective strategy for future prevention and treatment of events associated with cholinergic crises.

Molecular detection of M. tuberculosis and M. bovis and hematological and biochemical analyses in agricultural sprayers exposed to pesticides: A cross-sectional study in Punjab, Pakistan during 2014-2016

We determined the correlation between a pesticide exposure, physical health and susceptibility toward tuberculosis along with hematological indices and liver enzymes' alterations in sprayers exposed to pesticides. Molecular detection of Mycobacterium tuberculosis and Mycobacterium bovis was detected by targeting histone-like protein (hupB) gene. The WBC (white blood cells) and RBC (red blood cells) levels of male sprayers and non-sprayers were significantly different (P<0.05). In female spray workers, the WBC and neutrophils levels were significantly different as compared with non-sprayers. Overall, in both male and female pesticide-exposed sprayers, mean values of alanine amino transferase and aspartate amino transferase were higher as compared with unexposed workers. M. Tuberculosis were detected in 15% male sprayers and 36% female sprayers while, M. bovis was detected in 5% male sprayers and 10% female sprayers. A χ²-test indicated that there existed a significant different (P<0.05) between positive and negative M. tuberculosis and M. bovis in both male/female spray workers out of total. The susceptibility of pesticide-exposed sprayers to tuberculosis and alterations in hematology and liver enzymes is crucial for health. Toxic effects of pesticides may lead to a weak immune system and increased tuberculosis susceptibility.

Discovery and identification of O, O-diethyl O-(4-(5-phenyl-4, 5-dihydroisoxazol-3-yl) phenyl) phosphorothioate (XP-1408) as a novel mode of action of organophosphorus insecticides

Organophosphorus (OP) insecticides play an important role in pest control. Many OP insecticides have been removed from the market because of their high toxicity to humans. We designed and synthesized a new OP insecticide with the goal of providing a low cost, and less toxic insecticide. The mode of action of O, O-diethyl O-(4-(5-phenyl-4, 5-dihydroisoxazol-3-yl) phenyl) phosphorothioate (XP-1408) was studied in Drosophila melanogaster. Bioassays showed that XP-1408 at a concentration of 50 mg/L delayed larval development. Molecular docking into Drosophila acetylcholinesterase (AChE) and voltage-gated sodium channels suggested that XP-1408 fitted into their active sites and could be inhibitory. Whole-cell patch clamp recordings indicated that XP-1408 exhibited synergistic effects involving the inhibition of cholinergic synaptic transmission and blockage of voltage-gated potassium (Kv) channels and sodium (Nav) channels. In conclusion, the multiple actions of XP-1408 rendered it as a lead compound for formulating OP insecticides with a novel mode of action.

Potential contribution of insecticide exposure and development of obesity and type 2 diabetes

The introduction of insecticides has greatly improved agricultural productivity and human nutrition; however, the wide use of insecticides has also sparked growing concern over their health impacts. Increased rate of cancers, neurodegenerative disorders, reproductive dysfunction, birth defects, respiratory diseases, cardiovascular diseases and aging have been linked with insecticide exposure. Meanwhile, a growing body of evidence is suggesting that exposure to insecticides can also potentiate the risk of obesity and type 2 diabetes. This review summarizes the relationship between insecticide exposure and development of obesity and type 2 diabetes using epidemiological and rodent animal studies, including potential mechanisms. The evidence as a whole suggests that exposure to insecticides is linked to increased risk of obesity and type 2 diabetes.

Contributing Factors for Morbidity and Mortality in Patients with Organophosphate Poisoning on Mechanical Ventilation: A Retrospective Study in a Teaching Hospital

INTRODUCTION

One of the most common causes of poisoning in agricultural based developing countries like India is due to Organophosphorus (OP) compound. Its widespread use and easy availability has increased the likelihood of poisoning with these compounds.

AIM

To study the morbidity and mortality in patients with acute OP poisoning requiring mechanical ventilation.

MATERIALS AND METHODS

This was a retrospective study constituting patients of all age groups admitted to the Intensive Care Unit (ICU) with diagnosis of OP poisoning between January 2015 to December 2015. Of 66 OP poisoning cases those patients who went against medical advice, 20 were excluded from the study and thus 46 patients were included. Diagnosis was performed from the history taken either from the patient or from the patient's relatives and presenting symptoms. Demographic data, month of the year, age of patient, mode of poisoning, cholinesterase levels, duration of mechanical ventilation and mortality were recorded. Data are presented as mean±SD.

RESULTS

A 97.83% (45/46) of cases were suicidal. Out of 46, 9 were intubated and mechanically ventilated. Duration of mechanical ventilation varied from less than 48 hours to more than 7 days. Mortality rate was 50%, 0% and 100% in those who required mechanical ventilation for more than 7 days, 2 to 7 days and <2days respectively. None of the predictors like age, severity of poisoning, cholinesterase levels and duration of ventilation were independent predictors of death and all of them contributed to the mortality. Overall mortality rate in those who required mechanical ventilation was 22.22%.

CONCLUSION

Morbidity and mortality due to OP poisoning is directly proportional to the age, severity of poisoning and duration of mechanical ventilation and inversely proportional to serum cholinesterase level.

SAR study to find optimal cholinesterase reactivator against organophosphorous nerve agents and pesticides

Irreversible inhibition of acetylcholinesterase (AChE) by organophosphates leads to many failures in living organism and ultimately in death. Organophosphorus compounds developed as nerve agents such as tabun, sarin, soman, VX and others belong to the most toxic chemical warfare agents and are one of the biggest threats to the modern civilization. Moreover, misuse of nerve agents together with organophosphorus pesticides (e.g. malathion, paraoxon, chlorpyrifos, etc.) which are annually implicated in millions of intoxications and hundreds of thousand deaths reminds us of insufficient protection against these compounds. Basic treatments for these intoxications are based on immediate administration of atropine and acetylcholinesterase reactivators which are currently represented by mono- or bis-pyridinium aldoximes. However, these antidotes are not sufficient to ensure 100 % treatment efficacy even they are administered immediately after intoxication, and in general, they possess several drawbacks. Herein, we have reviewed new efforts leading to the development of novel reactivators and proposition of new promising strategies to design novel and effective antidotes. Structure-activity relationships and biological activities of recently proposed acetylcholinesterase reactivators are discussed and summarized. Among further modifications of known oximes, the main attention has been paid to dual binding site ligands of AChE as the current mainstream strategy. We have also discussed new chemical entities as potential replacement of oxime functional group.

Increased morbidity and mortality in acute human organophosphate-poisoned patients treated by oximes: a meta-analysis of clinical trials

Organophosphates are one of the most common causes of poisoning, especially in the Third world, with high morbidity and mortality. The treatment of this type of poisoning involves the use of atropine and oximes. Atropine has been used successfully in large doses to counteract the muscarinic effects of organophosphate poisoning, but the efficacy of oximes in the management of this poisoning remains under question. In this study, we undertook a meta-analysis by reviewing all clinical trials to evaluate the efficacy of oximes in the management of organophosphate poisoning. The databases of PUBMED, EMBASE, Cochrane, SCOPUS, and the search engine of Google were searched for all clinical trials on the use of oximes in organophosphate poisoning. The inclusion criteria were death, development of intermediate syndrome, and need for ventilation. Six clinical trials met the inclusion criteria and were included in the metaanalysis. The x2 tests for heterogeneity (P–0.25, 0.16, and 0.33, respectively) indicated that the included studies were not significantly heterogeneous and could be combined. A significant relative risk (P–0.0017) for death among oxime-exposed was 2.17 (95% CI of 1.34 / 3.51). The ‘need for ventilation’ in patients who received oxime was higher (P–0.03) than those who did not receive oxime with a relative risk of 1.53 (1.16 / 2.02). The incidence of ‘intermediate syndrome’ for oximeexposed patients was significantly higher (P–0.01) than oxime non-exposed patients with a relative risk of 1.57 (95% CI 1.11 / 2.11). It can be concluded that oximes are not effective in the management of organophosphate-poisoned patients and, surprisingly, they can be dangerous and worsen the patient's clinical situation.

The effect of plasmapheresis on plasma cholinesterase levels in a patient with organophosphate poisoning

Objective: To describe the role of plasmapheresis in management of organophosphate poisonings. Design: Case report. Setting: A medical intensive care unit of a medical faculty. Patient: A patient with organophosphate poisoning whose cholinesterase levels continuously decline and then increase up to a normal level after plasmapheresis is performed for his sepsis. Interventions: Plasmapheresis with fresh frozen plasma. Measurements and main results: Baseline plasma cholinesterase (ChE) level was 4001 IU/L (normal values: 4000-10000 IU/L). Aspiration pneumonia was developed on day 3, and sepsis occurred on day 5. During this period, ChE levels gradually decreased. On day 5, plasmapheresis was performed for sepsis. Interestingly, plasma ChE levels increased from 2101 IU/L to 6144 IU/L after plasmapheresis. Atropine and pralidoxime were stopped, and a high level of ChE continued during hospitalization. The patient was successfully weaned from mechanical ventilation 3 days after plasmapheresis. Conclusion: Plasma exchange therapy may be considered for patients with organophosphate poisoning unresponsive to atropine and pralidoxime.

Mitigation of diazinon-induced cardiovascular and renal dysfunction by gallic acid

Studies of the link between environmental pollutants and cardiovascular dysfunction, neglected for decades, have recently provided new insights into the pathology and consequences of these killers. In this study, rats were divided into four groups, each containing 10 rats. The rats in group one served as controls and were administered normal saline, whereas the rats in group two were orally gavaged with 3 mg/kg of diazinon (DZN) alone for twenty one consecutive days. The rats in groups 3 and 4 were administered respective 60 mg/kg and 120 mg/kg gallic acid (GA) in addition to DZN for twenty one consecutive days. Exposure of rats to diazinon significantly (p<0.05) reduced the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and reduced glutathione (GSH) content. Malondialdehyde, hydrogen peroxide (H2O2) and nitric oxide (NO) contents were also significantly (p<0.05) elevated following DZN exposure. DZN further caused a significant (p<0.05) decrease of heart rate and QT interval prolongation. Hematologic analysis revealed significant reduction (p<0.05) in packed cell volume (PCV), hemoglobin concentration (Hb), red blood cell (RBC) count, and total white blood cell count of rats administered only DZN. Observations in this study suggest a modulatory role of gallic acid in diazinon-induced anemia and associated cardiovascular dysfunction in rats. Treatment with gallic acid reversed the oxidative stress markers studied, increased the antioxidant defence system and reduced deleterious effects on hematological parameters in rats. Pathologic findings of the heart and kidney were also found to be lessened.

Vapor inhalation exposure to soman in conscious untreated rats: preliminary assessment of neurotoxicity

Neurological toxicity and brain injury following vapor inhalation exposure to the chemical warfare nerve agent (CWNA) soman (GD) were examined in untreated non-anesthetized rats. In this study, male Sprague-Dawley rats (300-350 g) were exposed to 600 mg × min/m(3) of soman or vehicle in a customized head-out inhalation system for 7 min. Convulsant animals were observed for clinical signs and various regions of the brain (dorsolateral thalamus, basolateral amygdala, piriform cortex, and lateral cortex) were collected for pathological observations 24 h post-exposure. Signs of CWNA-induced cholinergic crises including salivation, lacrimation, increased urination and defecation, and tremors were observed in all soman-exposed animals. Soman-exposed animals at 24 h post-exposure lost 11% of their body weight in comparison to 2% in vehicle-exposed animals. Whole blood acetylcholinesterase (AChE) activity was significantly inhibited in all soman-exposed groups in comparison to controls. Brain injury was confirmed by the neurological assessment of hematoxylin-eosin (H&E) staining and microscopy in the piriform cortex, dorsolateral thalamus, basolateral amygdala, and lateral cortex. Severe damage including prominent lesions, edematous, congested, and/or hemorrhagic tissues was observed in the piriform cortex, dorsolateral thalamus, and lateral cortex in soman-exposed animals 24 h post-exposure, while only minimal damage was observed in the basolateral amygdala. These results indicate that inhalation exposure to soman vapor causes neurological toxicity and brain injury in untreated unanesthetized rats. This study demonstrates the ability of the described soman vapor inhalation exposure model to cause neurological damage 24 h post-exposure in rats.

Management of exogenous intoxication by carbamates and organophosphates at an emergency unit

Summary Objectives: to evaluate and indicate the procedure to be followed in the health unit, both for diagnosis and the treatment of acute exogenous intoxications by carbamates or organophosphates. Methods: a descriptive study based on retrospective analysis of the clinical history of patients diagnosed with intoxication by carbamates or organophosphates admitted at the emergency unit of the Hospital de Urgências de Sergipe Governador João Alves (HUSE) between January and December of 2012. Some criteria were evaluated, such as: intoxicating agent; patient's age and gender; place of event, cause, circumstances and severity of the intoxication; as well as signs and symptoms of the muscarinic, nicotinic and neurological effects. Results: seventy patients (average age: 25±19.97) formed the study's population. It was observed that 77.14% of them suffered carbamate intoxication. However, organophosphate intoxications were more severe, with 68.75% of patients presenting moderate to severe forms. Suicide attempt was the leading cause of poisoning, with 62 cases (88.57% of total). Atropine administration was an effective therapeutic approach for treating signs and symptoms, which included sialorrhea (p=0.0006), nausea (p=0. 0029) and emesis (p lt0.0001). The use of activated charcoal was shown effective, both in combating the signs and symptoms presented by both patient groups (p <0.0001). Conclusion: it is concluded that the use of atropine and activated charcoal is highly effective to treat the signs and symptoms developed by patients presenting acute exogenous intoxication by carbamates or organophosphates.

Predictors of Morbidity and Mortality in Organophosphorus Poisoning: A Case Study in Rural Hospital in Karnataka, India

Background:

Organophosphorus (OP) pesticides poisoning can result from occupational, accidental or intentional exposure. Clinical manifestations include cholinergic syndromes, central nervous (CNS) system and cardiovascular disorders. Death is usually due to cardiovascular and respiratory failure.

Aim:

To evaluate various parameters that can predict outcome of patients in OP poisoning.

Materials and Methods:

A prospective study conducted in Department of Medicine, Adichunchingiri Institute Of medical Sciences and Research Centre, Karnataka, over period of 1 year. Diagnosis of OP poisoning was based on clinical history of exposure to OP compound and low serum pseudocholinesterase levels.

Results:

In the present study 133 patients were enrolled, out of which 98.5% were suicidal cases and only 1.5% had accidental exposure. Majority of cases were young male, with F/M ratio 1:3.2. Mortality rates were higher in younger people and in patients who required prolonged ventilator support. The mortality rate was directly proportional to amount of poison consumed, lag time, organ failure (Acute Renal Failure) and plasma pseudocholinesterase levels. Acute complications were frequently noted and were related to morbidity and mortality. No strict relationship was found between liver dysfunction, electrolyte disturbance and clinical outcome.

Conclusion:

This case study concluded that mortality is directly proportionate to the lag time, amount of OP substances consumed, clinical severity, pseudocholinesterase levels, Acute renal failure and duration of ventilatory support. This study highlights the importance of rapid diagnosis, and initiation of early and effective treatment, which may result in less number complications and also decreases the mortality rates.