Clinical and sociodemographic features of acute carbamate and organophosphate poisoning: a study of 70 adult patients in north Jordan

Case Report

The illegal practice of combining organophosphates (OPs) with other compounds such as carbamates and pyrethroids, creating 'streetpesticides', is common in South Africa. These agents contain mostly unknown quantities of unregulated toxins and contribute to atypicaland unpredictable clinical presentations following human ingestion. We present such a case in a patient with intentional rodenticideingestion. The initial presentation in the emergency department was a classic cholinergic toxidrome, and clinical resolution was achievedafter provision of atropine. This was followed 12 hours later by an acute decompensation resulting from an apparent sympatheticallydriven episode of autonomic instability and acute pulmonary oedema requiring immediate respiratory and haemodynamic support. In ourdiscussion, we explore this secondary decompensation and suggest various pathophysiological explanations for this atypical clinical coursefollowing what had appeared to be OP poisoning. The patient was discharged home after a total of 6 days in hospital.

Assessment of the Serum Glucose/Potassium GLU/K Ratio as a Predictor of Intermediate Syndrome Following Acute Anticholinesterase Exposure

BACKGROUND

The widespread use of anticholinesterase-containing pesticides accounts for the considerable morbidity and mortality in Egypt and worldwide.

AIM

Few studies have investigated the predictors of intermediate syndrome (IMS). Therefore, in this study, we assessed the adequacy of the serum glucose/potassium (GLU/K) ratio as an early reliable tool to predict IMS incidence following intoxication with acute anticholinesterase compounds.

METHODS

A prospective cross-sectional study was conducted among patients who presented to Tanta University Poison Control Center, Egypt, and were diagnosed with acute anticholinesterase intoxication between January and August, 2021. Patients were categorized based on the primary outcome into IMS (+) and IMS (-) groups.

RESULTS

Overall, 243 patients were included, among whom 44 (18.1%) had IMS as the complication. Younger individuals with age ranging between 18 and <25 years constituted the main exposed age category in both groups. Vomiting and abdominal colic were the most commonly noted complaints in the included patients (94.2% and 63.8% of patients, respectively). The delay, length of hospital stay, mean blood pressure, O₂ saturation, Glasgow Coma Scale score, random blood glucose level, K concentration, GLU/K ratio, and dose of atropine administered were significant IMS predictors on an individual basis, and the GLU/K ratio was the most significant IMS predictor. At a cutoff value of >41.07%, the GLU/K ratio could significantly predict IMS (areas under the curves = 0.971, p < 0.001) with 93% accuracy, 93.2% sensitivity, and 93% specificity.

CONCLUSION

Although the clear pathophysiology of IMS remains to be elucidated, our results provide insight into the significant contribution of neurological affection, apart from the well-known direct toxic effect on muscles. Moreover, we demonstrated a significant association between the development of IMS and severity of organophosphorus compounds' exposure. Physicians should be vigilant to detect IMS early upon admission using the GLU/K ratio, which is a useful early IMS predictor.

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.

Organophosphate pesticide exposure prenatally influence on pregnancy outcomes

BACKGROUND

Organophosphorus (OP) pesticides are widely used worldwide. The effect of OP exposure during pregnancy on the offspring is inconsistent in the current literature. Moreover, similar studies in the Middle East are lacking.

PURPOSE

To examine the effects of OP exposure in utero on the outcome of pregnancies in an agricultural region in Jordan.

METHOD

A prospective study, employing a questionnaire to collect women demographic data. Hospital records were collected for newborns' birth data. In addition, urine samples during the third trimester were collected from pregnant women and then analyzed for six OP metabolites to measure exposure.

RESULTS

One of the metabolites, DEDTP, was negatively correlated with gestational age and Apgar scores 1 and 5. There were no other significant associations.

CONCLUSIONS

Exposure to OP during pregnancy is not highly associated with any negative anthropometric characteristics of the newborns; it is probably offset by other factors.

Severe Hypothermia Causing Ventricular Arrhythmia in Organophosphorus Poisoning

Organophosphorus poisoning cases are routinely treated across all Intensive Care Units adjoining the rural areas where agriculture is the main source of income. We present a unique case of severe hypothermia seen in a case of organophosphorus poisoning, which led to electrocardiogram disturbances and life-threatening arrhythmias.

Efficacy of Recommended Prehospital Human Equivalent Doses of Atropine and Pralidoxime Against the Toxic Effects of Carbamate Poisoning in the Hartley Guinea Pig

PURPOSE

Aldicarb and methomyl are carbamate pesticides commonly implicated in human poisonings. The primary toxic mechanism of action for carbamate poisoning is cholinesterase (ChE) inhibition. As such, it is logical to assume that the currently accepted therapies for organophosphate poisoning (muscarinic antagonist atropine and the oxime acetylcholinesterase reactivator pralidoxime chloride [2-PAM Cl]) could afford therapeutic protection. However, oximes have been shown to be contraindicated for poisoning by some carbamates.

METHODS

A protective ratio study was conducted in guinea pigs to evaluate the efficacy of atropine and 2-PAM Cl. The ChE activity was determined in both the blood and the cerebral cortex.

RESULTS

Coadministration of atropine free base (0.4 mg/kg) and 2-PAM Cl (25.7 mg/kg) demonstrated protective ratios of 2 and 3 against aldicarb and methomyl, respectively, relative to saline. The data reported here show that this protection was primarily mediated by the action of atropine. The reactivator 2-PAM Cl had neither positive nor negative effects on survival. Both blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were significantly reduced at 15 minutes postchallenge but gradually returned to normal within 24 hours. Analysis of cerebral cortex showed that BChE, but not AChE, activity was reduced in animals that succumbed prior to 24 hours after challenge.

CONCLUSION

The results suggest that coadministration of atropine and 2-PAM Cl at the currently recommended human equivalent doses for use in the prehospital setting to treat organophosphorus nerve agent and pesticide poisoning would likely also be effective against aldicarb or methomyl poisoning.

Temperature changes among organophosphate poisoned patients, Tehran- Iran

Background

Acute poisoning with organophosphorus compounds (OPs) is a major global clinical problem in the developing countries. There have been many animal studies and few human surveys on the effects of organophosphorus pesticide (OP) poisoning on thermoregulation. The aim of this prospective study was to document the pattern of tympanic temperature changes among OP poisoned patients throughout the length of their hospital stay.

Methods

60 patients with diagnose of organophosphate poisoning were included in this study. Questioner was filled out by trained nurses including demographic, clinical and paraclinical data. Tympanic temperature and Pulse rate data of the cases were collected on five- occasions after admission.

Results

There were 41 (68.3%) male and 19 (31.7%) female, with a mean age of 34.4 ±19.4 years (range 13–89 years). Forty five patients had intentional poisoning for suicidal attempt. At the time of entry, the mean tympanic temperature, pulse rate, respiratory rate and blood pressure (systolic and diastolic) of the OP poisoned patients were respectively 37.1+/−0.6°C (36.0- 39.5), 91+/−18 (55–145), 18+/−5.6 (8–44), 116+/−20 mm Hg (70–170) and 75+/−11.6 mm Hg (40–110). 41.7% of the cases had serum butyryl cholinesterase activities (BChE) ≥ 50% normal (≥1600 mU/ml). Our patients had normal temperature at the time entry (mean = 37.1). Tympanic temperature decreasing below 36°C was not detected among the patients during the study period. A rise in mean tympanic temperature was found after atropine administration.

Conclusion

Our study showed hypothermia was not considerable factor among organophosphate poisoned patients, although more studies with similar situations in tropical countries are needed.

Occupational exposure to neurotoxic substances in Asian countries - challenges and approaches

The fact that a conference on neurotoxicity was held in China triggered the idea to provide an insight into occupational diseases, their development and the approaches to investigate them in Asian countries. A historical review, a meta-analysis, and studies on humans and animals provide impressions on past and current problems. The Korean example showed that each newly introduced industry is accompanied by its own problems as regards occupational diseases. Mercury and carbon disulfide were of importance in the beginning, whereas solvents and manganese became important later. Outbreaks of diseases were important reasons to guide both the public and the governmental attention to prevention and allowed within a relatively short time considerable progress. As the example on the replacement of 2-bromopropane by 1-bromopropane showed, also the introduction of chemicals that are more beneficial for the environment may result in additional occupational risks. A lower mutagenicity of 1-bromopopane was shown to be associated with a greater neurotoxicity in Japanese studies. Although occupational health and diseases are commonly related to adults, child workers exposed to solvents were examined in a Lebanese study. The study started outlining the health hazards in young workers because they might be at a much greater risk due to the not yet completed maturation of their nervous system. That some occupational diseases are not yet a focus of prevention was shown by the study on pesticides. If at all, the serious health consequences resulting from excessive exposure were investigated. Research enabling precautionary actions was not available from the international literature. Despite globalization the knowledge on occupational diseases is not yet "globalized" and each country obviously undergoes its own development triggered by local experiences. Economic development that requires a healthy workforce, but also public interest that challenges governmental regulations further efforts on the prevention of occupational diseases. The paper reflects a summary of the talks presented at the symposium "Occupational Neurotoxicities in Asian Countries" as part of the 11th International Symposium on Neurobehavioral Methods and Effects in Occupational and Environmental Health.

Hypothermia and Fever after organophosphorus poisoning in humans--a prospective case series

There have been many animal studies on the effects of organophosphorus pesticide (OP) poisoning on thermoregulation with inconsistent results. There have been no prospective human studies. Our aim was to document the changes in body temperature with OP poisoning. A prospective study was conducted in a rural hospital in Polonnaruwa, Sri Lanka. We collected data on sequential patients with OP poisoning and analyzed 12 patients selected from 53 presentations who had overt signs and symptoms of OP poisoning and who had not received atropine prior to arrival. All patients subsequently received specific management with atropine and/or pralidoxime and general supportive care. Tympanic temperature, ambient temperature, heart rate, and clinical examination and interventions were recorded prospectively throughout their hospitalization. Initial hypothermia as low as 32°C was observed in untreated patients. Tympanic temperature increased over time from an early hypothermia (<35°C in 6/12 patients) to later fever (7/12 patients >38°C at some later point). While some of the late high temperatures occurred in the setting of marked tachycardia, it was also apparent that in some cases fever was not accompanied by tachycardia, making excessive atropine or severe infection an unlikely explanation for all the fevers. In humans, OP poisoning causes an initial hypothermia, and this is followed by a period of normal to high body temperature. Atropine and respiratory complications may contribute to fever but do not account for all cases.

A fatal waterborne outbreak of pesticide poisoning caused by damaged pipelines, sindhikela, bolangir, orissa, India, 2008

Introduction. We investigated a cluster of pesticide poisoning in Orissa. Methods. We searched the village for cases of vomiting and sweating on 2 February 2008. We described the outbreak by time, place, and person. We compared cases with controls. Results. We identified 65 cases (two deaths; attack rate: 12 per 1000; case fatality: 3%). The epidemic curve suggested a point source outbreak, and cases clustered close to a roadside eatery. Consumption of water from a specific source (odds ratio [OR]: 35, confidence interval [CI]: 13-93) and eating in the eatery (OR: 2.3, CI: 1.1-4.7) was associated with illness. On 31 January 2008, villagers had used pesticides to kill street dogs and had discarded leftovers in the drains. Damaged pipelines located beneath and supplying water may have aspirated the pesticide during the nocturnal negative pressure phase and rinsed it off the next morning in the water supply. Conclusions. Innapropriate use of pesticides contaminated the water supply and caused this outbreak. Education programs and regulations need to be combined to ensure a safer use of pesticides in India.

Influence of atropine therapy on fenthion-induced pancreatitis

OBJECTIVE

We searched the influence of dose and timing of atropine therapy in fenthion-induced pancreatitis model.

METHODS

All rats were intoxicated with fenthion except the control group. Two milligrams of atropine was administered for 24 hours in a high dose atropine group while a low dose atropine group received 100 micrograms of atropine for 24 hours. One group received 2 milligrams of atropine in the first four hours of intoxication while the other group received 2 milligrams of atropine in the last four hours before sacrifice. All rats were sacrificed 24 hours after intoxication. Pseudo-cholinesterase and lipase concentrations and histopathological markers of pancreatitis were studied.

RESULTS

None of the models in this study completely prevented pancreatitis, however high dose atropine that is administered for 24 hours or the first four hours after intoxication prevented severe pancreatitis.

CONCLUSION

Atropine administration influence on fenthion-induced pancreatitis should be studied for other organophosphates in animals and humans.

Is there a relationship between the blood cholinesterase and QTc interval in the patients with acute organophosphate poisoning?

Organophosphates cause poisoning as a result of the excessive accumulation of acetylcholine at the cholinergic synapses due to inhibition of acetylcholinesterase (ChE). In the literature, it has been reported that there have been electrocardiographic abnormalities, including QT-interval prolongation in most patients with acute organophosphate poisoning (OPP), and a relation between blood ChE level and clinical severity in acute OPP. The aim of this study is to assess the relationship between blood ChE level and QTc interval in the patients with acute OPP. This retrospective study consists of 20 patients admitted to the emergency intensive care unit. A total of 93 QTc interval and blood ChE measures obtained on the same day from 20 cases were compared for their correlation. There were prolonged QTc intervals in 35.4% of the ECGs. There was a negative correlation between QTc interval and blood ChE measures. In following up the patients with acute OPP, QTc interval may be useful when blood ChE levels are low and may provide complementary information concerning the severity of poisoning. However, further prospective studies, supporting the present results, are needed.

Influence of Different Atropine Therapy Strategies on Fenthion-Induced Organ Dysfunction in Rats

We studied the influence of dose and timing of atropine therapy on fenthion-induced organ dysfunction. Thirty-six rats were randomized into six groups. All rats in the five groups except the control group were intoxicated with fenthion. The high-dose atropine group received 2 mg/kg of atropine, whereas the low-dose group received 100 microg/kg of atropine every hour for 24 hr. One group received 2 mg/kg of atropine in the first 4 hr of intoxication while the other group received 2 mg/kg of atropine in the last 4 hr before killed, which for all rats was 24 hr after intoxication. Pseudocholinesterase and aspartate aminotransferase and alanine aminotransferase levels and histopathological markers of lung, brain and liver were studied. None of our atropine therapy strategies in this study totally prevented harm on the three organs. Although the high dose of atropine administered for 24 hr had the least harmful markers for lung, it also had the most harmful markers for brain and liver. We did not succeed in finding a unique therapy strategy in our models beneficial for all studied organs in fenthion intoxication in rats. Atropine administration strategy should be oriented for the most affected organ pathology in fenthion intoxication.

Acute organophosphate poisoning in university hospital emergency room patients

OBJECTS

In the present study, we evaluated patients who were admitted to our emergency department with a diagnosis of organophosphate poisoning and discussed clinical, social and demographic features.

METHODS

A retrospective study was conducted with organophosphate poisoning patients admitted to our emergency department between January 1995 and December 2004. Data regarding the age, sex, occupation, type of agent, route of poisoning, clinical effects of cholinergic overactivity, laboratory findings, and mortality rate were obtained from the patient files.

RESULTS

During the study period, 220 patients who had organophosphate poisoning with a known agent were admitted to the ED. The estimated mean admission time to the ED after the exposure was 3.9 +/- 3.1 (1-14) hours. There were 131 (59.5%) female and 89 (40.5%) male patients. The most affected age group was 15-24 years (40.5%), in both sexes. Oral ingestion (86.5%) was found to be the most common route of poisoning. The most frequent reason for poisoning was attempted suicide (75.9%). The most common organophosphate compounds exposed were dichlorvos, diazinon and parathion-methyl. The most frequent clinical signs were miosis, respiratory system findings, tachycardia, loss of consciousness, and hypertension. Twenty patients (9.1%) died due to sudden respiratory and cardiac arrest (45%), respiratory failure (25%), CNS depression (5%) and septic shock (25%).

CONCLUSION

We think that the appropriate use of these compounds, instruction of the public about their harmful effects and restriction of their uncontrolled sales by legal regulations can reduce the incidence of organophosphate poisoning.

The use of serial measurement of plasma cholinesterase in the management of acute poisoning with organophosphates and carbamates

OBJECTIVE

To evaluate the benefits of using serial measurements of plasma cholinesterase (butyrylcholinesterase, BuChE) activity in the management of cholinesterase inhibitor insecticidal poisoning.

METHOD

After establishing and validating BuChE activity test, and making it available for clinical service in the toxicology laboratory at Jordan University Hospital. Serial measurements of BuChE were performed on samples taken from 10 symptomatic patients presented with the manifestations of poisoning due to acetylcholinesterase inhibitor insecticides during the year 2001. The number of serial repeats of BuChE activity tests ranged from 2 to 4 and from 8 to 11 for patients with carbamates and organophosphates (OPs) poisoning, respectively. The results of serial measurement of BuChE obtained from each patient's samples were used to draw a curve; three different types of curves were obtained from all patients samples.

RESULT

The obtained curves were found to follow our three proposed curves, which support our point view regarding the importance of the proposed curves in the differential diagnosis and treatment of cholinesterase inhibitor pesticides poisoning.

CONCLUSION

This study pointed out the importance of utilizing serial measurements of BuChE activity in the diagnosis and the management of organophosphates and carbamates poisoning. The BuChE activity results were used to support diagnostic and prognostic criteria that guided patient management and follow up. Applying those curves to large number of patients' samples will enhance its credibility. The study also demonstrated the importance of direct contract between toxicologist and physician in treatment of the pesticides poisoned patients.

Intoxicações provocadas por agrotóxicos de uso agrícola na microrregião de Dourados, Mato Grosso do Sul, Brasil, no período de 1992 a 2002

As notificações de intoxicações e tentativas de suicídio provocadas por agrotóxicos na microrregião de Dourados, Mato Grosso do Sul, entre 1992 e 2002, foram avaliadas baseando-se nos registros do Centro Integrado de Vigilância Toxicológica da Secretaria de Saúde do estado. Foram notificadas 475 ocorrências no período, sendo 261 intoxicações (acidental ou ocupacional), 203 tentativas de suicídio e 11 eventos de causa indeterminada. O Município de Dourados apresentou a maior prevalência de intoxicações, por 100 mil habitantes, considerando a população rural, e Fátima do Sul a segunda maior prevalência de suicídios na microrregião. Correlações significativas foram encontradas entre intoxicação e tentativa de suicídio (r = 0,60; p < 0,05), e entre intoxicação e razão entre a área ocupada por culturas temporárias e área total do município (r = 0,68; p < 0,05). As intoxicações ocorreram predominantemente com homens (87,0%), mas a diferença entre tentativas de suicídio em homens e mulheres não foi acentuada (53,0 e 47,0%, respectivamente). Os eventos ocorreram principalmente entre outubro e março, e os inseticidas organofosforados monocrotofós e metamidofós foram os principais agrotóxicos envolvidos.

Uso de agrotóxicos e suicídios no Estado do Mato Grosso do Sul, Brasil

As prevalências das tentativas de suicídio provocadas pela exposição a agrotóxicos de uso agrícola no Estado do Mato Grosso do Sul, Brasil, ocorridas entre janeiro 1992 a dezembro 2002, foram avaliadas baseadas nos registros das notificações de intoxicação do Centro Integrado de Vigilância Toxicológica da Secretaria de Saúde do Estado. Dados populacionais e de produção agrícola foram obtidos do Instituto Brasileiro de Geografia e Estatística, e dados de suicídio por causas diversas da Secretaria de Estado de Saúde. Foram registradas 1.355 notificações de intoxicação, sendo 506 tentativas de suicídio que levaram a 139 óbitos. As microrregiões de Campo Grande e Dourados apresentam as maiores prevalências de tentativas de suicídio. Alta prevalência de suicídios por causas diversas também foi observada em Dourados, com uma tendência de crescimento nos últimos dez anos. Os resultados deste estudo indicaram a microrregião de Dourados como uma das mais críticas do Estado do Mato Grosso do Sul com relação à ingestão voluntária de agrotóxicos, demonstrando a necessidade de um programa de vigilância epidemiológica para melhor investigar estes eventos na população rural da região.

Suicide and exposure to organophosphate insecticides: cause or effect?

BACKGROUND

Suicide using pesticides as agent is recognized as a major cause of pesticide poisoning.

METHODS

A literature review of mortality and morbidity studies related to suicide among pesticide-exposed populations, and of human and animal studies of central nervous system toxicity related to organophosphate (OP) pesticides was performed.

RESULTS

Suicide rates are high in farming populations. Animal studies link OP exposure to serotonin disturbances in the central nervous system, which are implicated in depression and suicide in humans. Epidemiological studies conclude that acute and chronic OP exposure is associated with affective disorders. Case series and ecological studies also support a causal association between OP use and suicide.

CONCLUSIONS

OPs are not only agents for suicide. They may be part of the causal pathway. Emphasizing OPs solely as agents for suicide shifts responsibility for prevention to the individual, reducing corporate responsibility and limiting policy options available for control.

Influence of gender on thermoregulation and cholinesterase inhibition in the long-evans rat exposed to diazinon

Diazinon is an organophosphate (OP)-based, anticholinesterase insecticide that irreversibly inhibits acetylcholinesterase activity and produces cholinergic stimulation in central nervous system (CNS) and peripheral tissues. Our laboratory has found that OPs administered orally in rats induce a transient period of hypothermia followed by a delayed fever that persists for several days after exposure. There is little information on the thermoregulatory effects of diazinon. Core temperature (Tc) and motor activity (MA) were monitored by radiotelemetry in male and female rats of the Long-Evans strain dosed orally with diazinon (0 [corn-oil vehicle], 100, 200, or 300 mg/kg in males and 0, 50, 100, or 200 mg/kg in females). There was a dose-dependent decrease in Tc during the first night after treatment, with females exhibiting slightly greater sensitivity than males. MA was unaffected in females exposed to diazinon at doses of 50 to 200 mg/kg; MA of males was reduced during the first night after dosing with 300 mg/kg. There was a delayed elevation in Tc of males dosed with 200 and 300 mg/kg and females dosed with 50, 100, and 200 mg/kg diazinon. The elevated Tc was only manifested during d 2 and 3 after diazinon. Administration of 200 mg/kg sodium salicylate to females 48 h after being treated with 200 mg/kg diazinon led to a rapid abatement of the fever. Diazinon doses of 50 to 300 mg/kg led to 40% to 50% inhibition in plasma cholinesterase (ChE) activity 4 h after dosing, and females displayed a significantly slower recovery of ChE activity compared to males. When compared on a molar basis, the hypothermic response to diazinon was relatively small compared to other OPs such as chlorpyrifos. The delayed fever and efficacy of sodium salicylate to block diazinon-induced fever are similar to the effects of OPs chlorpyrifos and diisopropyl fluoro-phosphate (DFP).

The prevalence of pancreatitis in organophosphate poisonings

OBJECTIVE

The aim of this study was to evaluate the prevalence of pancreatitis in cases of organophosphate (OP) poisonings admitted to Yüzüncü Yil University Teaching Hospital over an 18-month period.

MATERIALS AND METHODS

A total of 47 patients of acute poisoning with OP insecticides attended the Emergency Department of the Yüzüncü Yil Medical School Hospital, from May 1999 to December 2000, and were prospectively studied. Serum amylase and lipase levels were studied with colorimetric assay. Serum SGOT, SGPT, LDH, CPK, K levels, leukocyte count and total hospitalization days were also evaluated.

RESULTS

Four of 47 patients had obviously elevated amylase and lipase levels (amylase >300 U/L, lipase >60 U/L). Only two of the patients with amylase levels between 100 and 300 U/L had also elevated levels of lipase. None of the patients with normal amylase levels had elevated levels of lipase. A total of 12.76% was diagnosed as acute pancreatitis.

CONCLUSION

Acute pancreatitis as a complication of OP intoxication is not a rare condition. In order to improve the outcome of OP poisoning, early diagnosis of acute pancreatitis is important and serum levels of amylase and lipase should be routinely considered carefully. In acute pancreatitis, serum levels of SGOT, SGPT, LDH and leukocyte counts may also be found to be elevated. However, serum K levels are only slightly decreased.

Severe fenthion intoxications due to ingestion and inhalation with survival outcome

Two cases of severe fenthion intoxication are presented. The first is a case of a psychiatric patient who attempted suicide with ingestion of the compound, and the second case was of a child exposed to the chemical agent by air spraying. Both patients were treated in the intensive care unit with atropine and pralidoxime and finally survived. Fenthion blood levels on admission were 2.7 and 0.95 microg/mL, respectively. Different concentrations of pralidoxime were added to the first patient's poisoned serum in order to assess in vitro the effect of pralidoxime on cholinesterase reactivation. The clinical and toxicological data of the poisonings are discussed, as well as the potential therapeutic use of pralidoxime in organophosphate intoxication.

Prolonged elevation in blood pressure in the unrestrained rat exposed to chlorpyrifos

Organophosphate (OP) pesticides are likely to alter the regulation of blood pressure (BP) because (i) BP control centers in the brain stem utilize cholinergic synapses and (ii) the irreversible inhibition of acetylcholinesterase activity by OP's causes cholinergic stimulation in the CNS. This study used radiotelemetric techniques to monitor systolic (S), diastolic (D), mean (M) BP, pulse pressure (systolic-diastolic), heart rate (HR), core temperature (T(c)), and motor activity in male Long-Evans rats treated with the OP pesticide chlorpyrifos (CHP) at doses of 0, 5, 10, and 25 mg/kg (p.o.) at 15:00 h 10 and 25 mg/kg CHP led to parallel elevations in S-BP, M-BP, and D-BP within 2 h after dosing. BP increased 15-20 mmHg above controls and increases persisted throughout the night and into the next day. HR decreased slightly in rats administered 25 but not 10 mg/kg CHP. T(c) was reduced by treatment with 25 mg/kg CHP and then increased above controls the next day. Motor activity was reduced by treatment with 25 but not 10 mg/kg CHP. Pulse pressure was elevated by 2-4 mmHg for 40 h after exposure to 10 and 25 mg/kg CHP. The increase in BP without an increase in HR suggests that CHP increases total peripheral resistance and may alter the baroreflex control of BP. Cholinergic stimulation of the CNS may explain the initial effects of CHP on BP; however, the persistent elevation suggests an involvement of neurohumoral pressor pathways.

Effect of central and peripheral cholinergic antagonists on chlorpyrifos-induced changes in body temperature in the rat

Exposure to the organophosphate (OP)-based pesticide chlorpyrifos (CHP) in the rat results in an initial period of hypothermia lasting < 24 h, followed by a fever lasting 48-72 h. The purpose of this study was to determine how cholinergic pathways participate in the mediation of the thermoregulatory effects of CHP. The corn oil (CO) vehicle or CHP (25 mg/kg; p.o.) was administered to female rats while core temperature (Tc) and motor activity (MA) were monitored by radiotelemetry. The peripheral muscarinic antagonist, methyl scopolamine (MS) and central antagonist, scopolamine (S) were administered during the period of CHP-induced hypothermia and fever. The hypothermia was attenuated by scopolamine but not by methyl scopolamine. The delayed fever was augmented by scopolamine but blocked by methyl scopolamine. The results indicate that CHP-induced hypothermia is mediated by cholinergic stimulation of heat loss pathways in CNS thermoregulatory centers. Peripheral cholinergic pathways appear to have a minimal role in mediating chlorpyrifos-induced hypothermia. On the other hand, the chlorpyrifos-induced fever appears to be mediated by a peripheral pathway that is blocked by methyl scopolamine. The data provides a possible explanation for the persistent fever in humans exposed to OP pesticides and treated with atropine. Methyl atropine or methyl scopolamine may be a more effective therapy in the treatment of the fever.

Organophosphorus poisoning and anaesthesia

Organophosphorus compounds, used as insecticides and agents of chemical warfare, are a major global cause of health problems. These irreversible inhibitors of cholinesterase produce three well-recognised clinical entities: the initial cholinergic phase, which is a medical emergency often requiring management in an intensive care unit; the intermediate syndrome, during which prolonged ventilatory care is necessary; and delayed polyneuropathy. In addition, disturbances of body temperature and endocrine function, electrolyte imbalances, immunological dysfunction and disorders of reproduction have been reported in animals and man. Vocal cord paralysis, pancreatitis, cardiac arrhythmias and a wide range of neuropsychiatric disorders are known to follow acute and chronic exposure to organophosphorus compounds. As a result of the inhibition of plasma cholinesterase, there can be increased sensitivity to drugs hydrolysed by this enzyme, e.g. suxamethonium and mivacurium. The inhibition of acetylcholinesterase causes dysfunction at the neuromuscular junction which can produce altered responses to nondepolarizing neuromuscular blockers. Anaesthetists may encounter patients exposed to organophosphorus compounds either following acute poisoning, trauma (warfare) or as patients with a wide range of nonspecific disorders presenting for surgery. The traditional use of oximes and atropine in treatment has failed to reduce the morbidity and mortality associated with poisoning. The roles of agents that have reduced the toxicity of organophosphorus compounds in animal experiments are discussed as potential therapeutic agents. There is an urgent need for accurate information on the problems associated with exposure to organophosphorus compounds. This would best be achieved by collaborative research between technologically advanced countries and developing countries, where organophosphorus compounds are a leading cause of ill health.

Are circulating cytokines interleukin-6 and tumor necrosis factor alpha involved in chlorpyrifos-induced fever?

Oral exposure to chlorpyrifos (CHP) in the rat results in an initial hypothermic response followed by a delayed fever. Fever from infection is mediated by the release of cytokines, including interleukin-6 (IL-6) and tumor necrosis factor (TNF alpha). This study determined if the CHP-induced fever involves cytokine-mediated mechanisms similar to that of infectious fevers. Long-Evans rats were gavaged with the corn oil vehicle or CHP (10-50 mg/kg). The rats were euthanized and blood collected at various times that corresponded with the hypothermic and febrile effects of CHP. Plasma IL-6, TNF alpha, cholinesterase activity (ChE), total iron, unsaturated iron binding capacity (UIBC), and zinc were measured. ChE activity was reduced by approximately 50% 4 h after CHP. There was no effect of CHP on IL-6 when measured during the period of CHP-induced hypothermia or fever. TNF alpha levels nearly doubled in female rats 48 h after 25 mg/kg CHP. The changes in plasma cytokine levels following CHP were relatively small when compared to > 1000-fold increase in IL-6 and > 10-fold rise in TNF alpha following lipopolysaccharide (E. coli; 50 microg/kg; i.p.)-induced fever. This does not preclude a role of cytokines in CHP-induced fever. Nonetheless, the data suggest that the delayed fever from CHP is unique, involving mechanisms other than TNF alpha and IL-6 release into the circulation characteristic of infectious fevers.

The clinical significance of hyperamylasemia in organophosphate poisoning

OBJECTIVE

Hyperamylasemia with a presumptive diagnosis of acute pancreatitis has been reported following organophosphate poisoning but there are no large-scale studies incorporating more specific diagnostic criteria.

METHODS

Retrospective review of the medical records of 159 patients with a diagnosis of organophosphate poisoning over 3 years. Serum amylase, pancreatic amylase, salivary amylase, lipase and cholinesterase levels, and the clinical manifestations were analyzed.

RESULTS

Serum amylase data was available for 121 of the 159 study patients. Hyperamylasemia (amylase > or = 360 U/L) was found in 44 patients (36%). Lipase was measured in 28 patients with hyperamylasemia; 9 of 28 had hyperlipasemia (lipase > or = 380 U/L). The finding of hyperamylasemia was closely related to clinical severity and presence of shock. A presumptive diagnosis of painless acute pancreatitis was diagnosed by hyperlipasemia associated with hyperamylasemia, clinical severity, serum LDH, and leukocyte counts. Two patients with presumptive pancreatitis died. Shock, coma, and hypoalbuminemia were the factors predicting fatality.

CONCLUSIONS

Hyperamylasemia is frequent in severe organophosphate poisoning. However, hyperamylasemia is not synonymous with acute pancreatitis and pancreatic amylase is not a reliable parameter in the diagnosis of organophosphate-induced pancreatitis due to its low sensitivity and specificity. Lipase assay is indicated in patients with hyperamylasemia for early diagnosis of pancreatitis. Proper image studies and even pathological examination are also needed to confirm the extent of pancreatic injury. With prompt diagnosis and appropriate treatment, a complete recovery can be anticipated unless the patient has otherwise unrelated complications.

Delayed febrile effects of chlorpyrifos: is there cross-tolerance to bacterial lipopolysaccharide?

Oral chlorpyrifos (CHP) induces hypothermia followed by a fever that persists for several days in the rat. To understand the neuro-immune mechanisms of CHP-induced fever, we compared the tolerance and cross-tolerance between CHP and the fever elicited by lipopolysaccharide (LPS) (Escherichia coli). Female rats were administered the corn oil (CO) vehicle or CHP (10 mg/kg; p.o.) daily for 4 days while core temperature (Tc) and motor activity (MA) were monitored by telemetry. There was a reduction in Tc followed by an elevation the next day after each CHP treatment. The day after the last CHP treatment, rats were administered saline or 50 microg/kg LPS (i.p.). CHP-treated rats had a smaller LPS fever that was attributed to their elevated baseline Tc. In another study, rats were dosed with saline or LPS daily for three days. By the time of the third LPS injection there was no febrile response, indicating tolerance to LPS. Rats were then dosed with CO or CHP (10 mg/kg) 24 h after the third LPS treatment. LPS-tolerant rats displayed an accentuated hypothermic and febrile response to CHP. Plasma cholinesterase activity was unaffected by repeated LPS treatment, suggesting that the metabolism of CHP in the liver was unaffected by LPS. Overall, the neural-immune mechanisms for LPS fever is distinct from that of CHP in view of marked difference in mechanisms of tolerance.

Quantitation of postmortem profenofos levels

CASE REPORT

An 88-year-old woman was found dead, and suicidal ingestion of profenofos, an organophosphate pesticide, was suspected.

METHOD

Gas chromatography-nitrogen phosphorus detection was employed for quantitation of profenofos after its identification by gas chromatography/mass spectrometry.

RESULTS

The levels of profenofos in whole blood, urine, and gastric contents were 1200 ng, 350 ng, and 3.35 mg/mL, respectively.

Poisons and fever

1. Dysfunction of the thermoregulatory system is one of many pathologies documented in experimental animals and humans exposed to toxic chemicals. The mechanism of action responsible for many types of poison-induced fevers is not understood. Some elevations in body temperature are attributed to the peripheral actions of some poisons that stimulate metabolic rate and cause a forced hyperthermia. Exposure to organophosphate (OP) pesticides and certain metal fumes appears to cause a prolonged, regulated elevation in body temperature (Tb). 2. Activation of cyclo-oxygenase (COX) and the production of prostaglandin (PG)E2 in central nervous system (CNS) thermoregulatory centres is required to elicit a fever. Activating the COX-PGE2 pathway by a poison may occur by one of three mechanisms: (i) induction of cell-mediated immune responses and the subsequent release of cytokines; (ii) induction of lipid peroxidation in the CNS; and (iii) direct neurochemical activation. 3. Radiotelemetric monitoring of core temperature in unstressed rodents has led to an experimental animal model of poison-induced fever. Rats administered the OP agents chlorpyrifos and diisopropyl fluorophosphate display an initial hypothermic response lasting approximately 24 h, followed by an elevation in diurnal core temperature for 24-72 h after exposure. The hyperthermia is apparently a result of the activation of the COX-PGE2 pathway because it is blocked by the anti-pyretic sodium salicylate. Overall, the delayed hyperthermia resulting from OP exposure involves activation of thermoregulatory pathways that may be similar to infection-mediated fever.

Behavioral thermoregulatory response to chlorpyrifos in the rat

Chlorpyrifos (CHP) is a heavily used organophosphorous-based insecticide that elicits thermoregulatory dysfunction in the rat characterized by an initial period of hypothermia followed by a delayed hyperthermia lasting 24-72 h after exposure. The purpose of the present study was to determine (1) if the delayed hyperthermia is linked to CHP-induced hypothermia and (2) if the hypothermia and delayed hyperthermia are regulated by the CNS thermoregulatory centers. Core temperature (Tc) and motor activity (MA) of female Long-Evans rats were monitored via radiotelemetry. Rats housed in a temperature gradient were administered the control vehicle or CHP (25 mg/kg (p.o.)) while Tc, MA and ambient temperature (Ta) preferred by rats in the gradient (i.e. selected Ta) were recorded. There was an initial reduction in Tc concomitant with a decrease in selected Taa A gradual recovery in Tc occurred during the first night along with a preference for warmer Ta's and depressed MA. The day after CHP there was an elevation in Tc but no change in selected Ta, suggesting that the delayed rise in Tc was regulated. In another experiment, the hypothermic effects of CHP (25 mg/kg (p.o.)) were blocked by raising Ta from 22 to 31 degrees C immediately after CHP administration. Non-heated rats administered CHP underwent a marked period of hypothermia followed by an elevation in diurnal Tc for 2 days. Heated rats showed no hypothermic response but did undergo a hyperthermic response 48 h after CHP. MA was reduced during the first night after CHP in both non-heated and heated groups. Overall, the CHP-induced hyperthermia is not dependent on the development of hypothermia. Behavioral thermoregulatory observations suggest that both hypothermia and hyperthermia are regulated by CNS thermoregulatory centers.