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Objective: There is insufficient evidence on the effectiveness of gastric lavage in organophosphorus poisoning. This study was done to quantitate the level of chlorpyrifos and quinalphos retrieved in gastric lavage fluid.Methods: Patients presenting within six hours of ingesting quinalphos or chlorpyrifos with International Program on Chemical Safety Poison Severity Score (IPCS PSS) grade 2 or more were included in the study. After the stabilisation of patients, gastric lavage was performed with alliquotes of 200 ml of normal saline till aspirate became clear. Quantification of the pesticide was done in the first 10 ml of lavage fluid aspirated out and in blood with gas chromatography with triple quadruple mass spectrometer (GC-MSMS).Results: There were six patients in each pesticide group. Mean time for reaching hospital after the ingestion of pesticide was 2.8 ± 1.1(range 1.25-6) hours. Median quantity of chlorpyrifos in the lavage fluid was 10.24 (IQR 14.36) µg/L and in quinalphos, it was 1360.62 (IQR 1691.2) µg/L. Other compounds detected in lavage fluid and confirmed in blood were endosulfan, diazinon, pirimiphos, pyridafenthion, pyrazophos, pirimiphos ethyl, and azinphos.Conclusion: Chlorpyrifos and quinalphos are detected in lavage fluid after one hour of ingestion and few milligrams are retrieved by gastric lavage. The presence of other pesticides including endosulfan were confirmed in lavage fluid.

Objective: There is insufficient evidence on the effectiveness of gastric lavage in organophosphorus poisoning. This study was done to quantitate the level of chlorpyrifos and quinalphos retrieved in gastric lavage fluid. Methods: Patients presenting within six hours of ingesting quinalphos or chlorpyrifos with International Program on Chemical Safety Poison Severity Score (IPCS PSS) grade 2 or more were included in the study. After the stabilisation of patients, gastric lavage was performed with alliquotes of 200 ml of normal saline till aspirate became clear. Quantification of the pesticide was done in the first 10 ml of lavage fluid aspirated out and in blood with gas chromatography with triple quadruple mass spectrometer (GC-MSMS). Results: There were six patients in each pesticide group. Mean time for reaching hospital after the ingestion of pesticide was 2.8 ± 1.1(range 1.25-6) hours. Median quantity of chlorpyrifos in the lavage fluid was 10.24 (IQR 14.36) µg/L and in quinalphos, it was 1360.62 (IQR 1691.2) µg/L. Other compounds detected in lavage fluid and confirmed in blood were endosulfan, diazinon, pirimiphos, pyridafenthion, pyrazophos, pirimiphos ethyl, and azinphos. Conclusion: Chlorpyrifos and quinalphos are detected in lavage fluid after one hour of ingestion and few milligrams are retrieved by gastric lavage. The presence of other pesticides including endosulfan were confirmed in lavage fluid. [ABSTRACT FROM AUTHOR]

Background: Human serum paraoxonase 1 (PON1) hydrolyzes organophosphate (OP) compounds and so significantly alters an individual’s susceptibility to the toxicity of these chemicals. The study was designed to assess the serum PON1 activity in a series of patients with OP poisoning. Methods: Suspected OP poisoning patients presented within 6 hours of consumption at emergency department were recruited. Demographic information of patients, clinical findings, treatments given, complications, length of hospital stay and clinical outcome were collected into datasheets. Patients were graded into moderate and severe poisoning. Serum PON1 was measured by ELISA method and serum cholinesterase by butyrylthiocholine method. Results: Mean serum PON1 level in patients with severe poisoning was significantly lower than those with moderate poisoning (426 ± 179 U/L vs. 868 ± 79 U/L, P < 0.001). Serum PON1 significantly correlated with serum cholinesterase levels (r = 0.400, P < 0.001) and negatively associated with total length of hospital stay (r = -0.338, P < 0.001), total atropine dose (r = -0.826, P < 0.001), serum amylase (r = -0.331, P < 0.001), lipase (r = 0.260, P = 0.011) and total creatinine kinase (r = -0.456, P < 0.001). Serum PON1 and cholinesterase levels were significantly lower in expired patients and those who required ventilation assistance as compared to recovered patients who did not require ventilation assistance. Conclusion: Lower PON1 activity was significantly associated with lower serum cholinesterase and poorer outcomes. PON1 activity may be considered as an indicator of prognosis in OP poisoning.

Background: Organophosphates (OPs) are regularly utilized as pesticides all over the world. Exposures to OPs cause countless cases of poisoning and death annually. Organophosphates inebriation generates a range of muscarinic, nicotinic, and cholinergic side effects including both central and peripheral nervous systems. OP compound’s simple accessibility is responsible for expanding rates of pesticide poisoning and the fact that it is a noteworthy reason for morbidity and mortality that presents general medical issues in a growing district. Methods: I performed a review of the published literature. The databases Medline, Embase, Scopus and Google Scholar were searched using the terms intermediate syndrome, organophosphate induces intermediate syndrome and organophosphate poisoning. Databases were merged and a duplicate was removed. Results: In intense organophosphate poisoning, serious and delayed acetylcholinesterase restraint comes with oxidative stress, identified in erythrocyte membranes, that takes place in the initial phases of poisoning and may add to the progress and seriousness of intermediate syndrome (IMS). Conclusion: It normally appears 2-4 days after presentation when the side effects and indications of the intense cholinergic disorder (e.g., muscle fasciculations, muscarinic signs) are not evident anymore. However, IMS has been considered as a noteworthy causative factor of organophosphate-related morbidity and mortality due to its incessant presence and potential occurrence of breathing malfunction. The aim of the article is to bring down the clear idea about the IMS.

Background: Organophosphate (OP) poisoning is a global issue, causing over 200,000 deaths annually especially in developing countries, such as Sri Lanka and India. Clinical presentation of a typical OP poisoning may follow three well-defined phases. The initial phase is an acute cholinergic crisis, after that Intermediate Syndrome (IMS) may develop within 24-96 hours, and lastly, Organophosphate-Induced Delayed Polyneuropathy (OPIDPN) may present after 2-3 weeks. The signs and symptoms of the IMS are weakness of the respiratory muscles, including the diaphragm, intercostal, accessory, neck, and proximal limbs muscles. The aim of this study was to highlight the clinical profile of the IMS following organophosphate poisoning. Methods: This descriptive, prospective, and cross-sectional study was conducted at the Teaching Hospital, Batticaloa, Sri Lanka, over a period of 6 months from March 1, 2017 to August 31, 2017. Results: Of the total 65 enrolled patients, 60% (n=39) were male. All patients ingested OP pesticide for deliberate self-harm and all of them had some degrees of initial cholinergic crises. The prevalence of IMS in the studied patients was 5.88%. All 5 patients with IMS had neck, facial and proximal limbs muscle weakness from whom, two cases (40%) had extra-ocular muscle paralysis. There was no in-hospital fatality among IMS patients. Conclusion: IMS is a rare and life-threatening problem in OP intoxication. Early diagnosis and intensive care management can prevent further complications and mortality. Prevalence of IMS in this study was lower than previous reports with almost similar clinical features.

Background: Deliberate self-harm (DSH) is a global problem which has steadily increased over the past few years in developing countries and has become as one of the major causes of morbidity and mortality in these countries. The aim of this prospective study was to analyze the prevalence of organophosphate poisoning among other acute DSH cases admitted to the medical ward at Batticaloa Teaching Hospital, Sri Lanka. We report the socio-demographic, and outcome of organophosphate poisoning. Method: The prospective study comprises of 121 cases of acute poisoning admitted at Batticaloa Teaching Hospital (BTH), Sri Lanka. This study was conducted for a period of three months from April 12 through July 12, 2017. Results: Among the subjects, 119 (98.34%) cases had intentional poisoning and only two cases (1.65%) accidental poisoning. Poisoning with organophosphate compounds (OP) 23 (19%) was the second leading type. There were 13 (56.5%) males and 10 (43.5%) females. Most of the patients were under the age group of 20-29 years old. 21 cases lived in rural areas and 2 in urban areas. Out of 23 patients, there were 2 (8.7%) deaths, 18 (78.3%) were discharged without any complications. Conclusion: DSH in Sri Lanka is reported to be associated with interpersonal conflict, short premeditation, as well as alcohol misuse among males.

Background: Human serum paraoxonase 1 (PON1) hydrolyzes organophosphate (OP) compounds and so significantly alters an individual's susceptibility to the toxicity of these chemicals. The study was designed to assess the serum PON1 activity in a series of patients with OP poisoning. Methods: Suspected OP poisoning patients presented within 6 hours of consumption at emergency department were recruited. Demographic information of patients, clinical findings, treatments given, complications, length of hospital stay and clinical outcome were collected into datasheets. Patients were graded into moderate and severe poisoning. Serum PON1 was measured by ELISA method and serum cholinesterase by butyrylthiocholine method. Results: Mean serum PON1 level in patients with severe poisoning was significantly lower than those with moderate poisoning (426 ± 179 U/L vs. 868 ± 79 U/L, P < 0.001). Serum PON1 significantly correlated with serum cholinesterase levels (r = 0.400, P < 0.001) and negatively associated with total length of hospital stay (r = -0.338, P < 0.001), total atropine dose (r = -0.826, P < 0.001), serum amylase (r = -0.331, P < 0.001), lipase (r = 0.260, P = 0.011) and total creatinine kinase (r = -0.456, P < 0.001). Serum PON1 and cholinesterase levels were significantly lower in expired patients and those who required ventilation assistance as compared to recovered patients who did not require ventilation assistance. Conclusion: Lower PON1 activity was significantly associated with lower serum cholinesterase and poorer outcomes. PON1 activity may be considered as an indicator of prognosis in OP poisoning. [ABSTRACT FROM AUTHOR]

Background: Organophosphates (OPs) are regularly utilized as pesticides all over the world. Exposures to OPs cause countless cases of poisoning and death annually. Organophosphates inebriation generates a range of muscarinic, nicotinic, and cholinergic side effects including both central and peripheral nervous systems. OP compound's simple accessibility is responsible for expanding rates of pesticide poisoning and the fact that it is a noteworthy reason for morbidity and mortality that presents general medical issues in a growing district. Methods: I performed a review of the published literature. The databases Medline, Embase, Scopus and Google Scholar were searched using the terms intermediate syndrome, organophosphate induces intermediate syndrome and organophosphate poisoning. Databases were merged and a duplicate was removed. Results: In intense organophosphate poisoning, serious and delayed acetylcholinesterase restraint comes with oxidative stress, identified in erythrocyte membranes, that takes place in the initial phases of poisoning and may add to the progress and seriousness of intermediate syndrome (IMS). Conclusion: It normally appears 2-4 days after presentation when the side effects and indications of the intense cholinergic disorder (e.g., muscle fasciculations, muscarinic signs) are not evident anymore. However, IMS has been considered as a noteworthy causative factor of organophosphate-related morbidity and mortality due to its incessant presence and potential occurrence of breathing malfunction. The aim of the article is to bring down the clear idea about the IMS. [ABSTRACT FROM AUTHOR]

Organophosphate (OP) compounds are frequently used agorchemicals for deliberate self-harm in some parts of the world resulting in high mortality and morbidity. Pralidoxime (2PAM) is the most widely used and trialed oxime for treatment of OP poisoning. There have been variations over the results of trials using 2PAM for OP poisoning. 2PAM therapy has led to favorable outcomes in some studies, whereas it has been associated with unfavorable outcomes or without benefit in the others. Why 2PAM works in some trials and why it does not in the others, has been a key question for medical toxicologists with no definite answer. In this systematic review, we sought to investigate possibilities of the variations in the results of different studies conducted on the effectiveness of 2PAM therapy for OP poisoning and we tried to provide solutions for future studies.

Background:Organophosphates are commercially available agrochemicals for pest control, but may be abused for deliberate self-poisoning. We report a case of suicidal ingestion of dimethoate, a moderately toxic organophosphate insecticide, which can cause refractory hemodynamic instability, and the successful use of methylene blue (MB) for counteracting this complication. Case Presentation: An unconscious 47-year-old man was referred to emergency department with history of dimethoate ingestion. He rapidly developed hypotension that was refractory to antidotes, resuscitative hydration and multiple vasopressors including norepinephrine, epinephrine and vasopressin. Pulmonary artery catheterization revealed high cardiac output and low peripheral vascular resistance consistent with distributive shock, a complication previously reported in the setting of acute dimethoate toxicity. MB was initiated for the patient and improved hemodynamic status (increased MAP, systolic and diastolic blood pressures) and seized vasopressor requirement. Laboratory tests revealed that on-admission plasma cholinesterase level and dimethoate serum level were 2247 U and 56 μg/mL, respectively. The patient required 2 week ICU course with eventual tracheotomy for ventilation and later transferred to step down level of care. Discussion:Although MB therapy has been reported to be useful in managing sepsis-induced hypotension, there has been no similar report of its use in organophosphate poisoning. Our patient had no objective evidence for sepsis, and MB infusion improved hemodynamics within 6 hours and the effect was continued even after discontinuation of the therapy. The underlying mechanism of dimethoate-induced hypotension might be related to increase in nitric oxide (NO) formation. MB is effective to inhibit NO synthase. Conclusion:MB treatment was effective to reverse hypotension and restore hemodynamic instability caused by dimethoate poisoning. This index case may pave way to further investigation of MB therapy for OP-induced hemodynamic instabilities.

Background: For effective treatment of organophosphate (OP) poisoning, development of a standardized protocol with flexible dose regimen for atropine and pralidoxime is an essential step. In this study, we aimed to assess the protocol devised in our setting; Bach Mai Hospital Poison Treatment Center, for treatment of OP poisoning that included a higher dose regimen of pralidoxime (2PAM). Methods: A protocol for treatment of OP poisoning was developed during 1995 to 1996, which included an atropinization scoring scale and a modification of 2PAM dose regimen. In this study, OP poisoned patients who were treated during 1997 to 2002 with the new protocol (study group or cases) were compared with historical control group which included OP poisoned patients treated between 1993 and 1994 prior to establishment of the new protocol. Results: One-hundred and eight cases and 54 controls were included. The cases and controls were not significantly different according to age, gender and plasma cholinesterase activity on admission from each other. There was no significant difference of mean duration of 2PAM therapy between the two groups. The controls received mean total 2PAM dose of 7.2±4.1 g, while the patients in the study group received 20.0±12.7 g which was 2.77 times higher than the dose for control group (P

Organophosphate (OP) poisoning is one of the most common causes of poisoning in developing countries especially in Southeastern Asia. Poisoning with phosphorus-containing organic chemicals or OP compounds can be managed with antidotes like oximes which are potential reactivators of acetylcholinesterase (AChE). The efficacy of oxime therapy in OP poisoned patients mainly depends upon various factors such as different dose plans, infusion rate of oximes, genetic differences of patients, type of oxime used and chemical nature of the OP compound ingested. Studies on pralidoxime kinetics in OP poisoned patients have shown that reactivation of AChE depends on the plasma concentration of oximes as well as OP compounds. The plasma concentration of oximes mainly depends on the dose plan from intermittent injection to continuous infusion after a loading dose. The incontrovertible fact is that the intermittent dosing of oximes results in deep troughs in blood pralidoxime/oxime levels (BPL) whereas continuous infusion of oximes maintains steady state plasma concentrations. Many published literature also highlighted pralidoxime via continuous infusion results in better outcomes with minimum fluctuation in BPL compared to intermittent dosing. At therapeutic doses, adverse effects of oximes are reported to be minimal. But high BPL is associated with some common adverse effects including dizziness, blurred vision and diastolic hypertension. Considering all the facts, it is important to note that kinetic studies of oximes are useful not only in deciding the dose regimen, but also in predicting the possible side-effects.

Background: It is becoming apparent that although inhibition of cholinesterase plays a key role in organophosphate (OP) toxicity, other factors are also important. One of the contributing factors for severity of OP poisoning is electrolyte imbalances such as hypokalemia. This study was aimed at evaluating the value of hypokalemia in association with plasma cholinesterase (PChE) levels in predicting morbidity and mortality of acute OP poisoning. Methods: In this cross sectional study patients with definitive diagnosis of OP poisoning were enrolled. Pre-interventional clinical features were observed and noted with severity assessment as per Proudfoot classification, along with measurement of serum potassium ion ([K+]) concentration and PChE level. Results: Fifty OP poisoned patients (33 men, 17 women) were enrolled with median age of 27.1 years. The most common clinical manifestation was congested conjunctiva (82%) followed by miosis (78%) and bronchorrhea (78%). A total of 21 cases presented with one or more severe clinical features according to Proudfoot classification. Among them, 61.9% of cases (13 out of 21) developed hypokalemia. Muscle weakness or fasciculation developed with mean serum [K+] of 3.31 ± 0.11. Ventilatory support was required at the mean serum [K+] of 3.27 ± 0.10 mmol/L. Fatality was noted when the mean serum [K+] reduced to 2.90 ± 0.06 mmol/L. Correlation of the clinical effects and serum [K+] was significant (P < 0.001). In addition, muscle weakness, fasciculation, convulsion and respiratory distress were associated with marked suppression of PChE (>75%). Death was mostly observed among patients who had respiratory distress associated with hypokalemia and grossly reduced PChE. Conclusion: For severe clinical features of OP poisoning, serum [K+] and PChE level are greatly reduced. Hence, these biochemical findings can be proposed as OP poisoning predictive markers. Clinicians and medical toxicologists should consider hypokalemia associated with reduced PChE level as alarming signs of poor prognosis in OP poisoned patients.

Background:Acute poisoning with organophosphorus (OP) pesticides is a common method of suicide and entails considerable mortality in Bangladesh. The objective of this study was to evaluate the effects and outcomes of a protocol for treatment of OP poisoning that included titrated incremental atropine as loading dose and slow infusion for maintenance. Methods:In this prospective descriptive case series, definitive OP poisoned patients were enrolled in an adult medicine unit of Dhaka Medical College Hospital from April 2006 to April 2007. Clinical examinations were done as soon as the patient entered the ward. Patient’s demographics, comorbid conditions and the occurrence of specific clinical outcomes including death, need for assisted ventilation and clinical complications were recorded. The patients were treated according to the protocol. Results: A total of 56 patients were enrolled over the study period. The median age of the study population was 22.5 years. Most patients were men (67.8%). The most common clinical presentation was miosis (58.9%). In total, 11 patients died (19.6%). Intermediate syndrome developed in 12 patients (21.4%) and 6 of them died. Assisted ventilation was required in 16 cases (28.5). Patients with diastolic blood pressure ≤ 70 mmHg and/or GCS ≤ 10 were significantly less likely to survive (P = 0.02, 0.006, respectively). Moreover, early respiratory failure (P < 0.001) and the need for assisted ventilation (P < 0.001) were significantly higher among deceased cases. The mortality rate in this study was similar to previous studies. The frequency of atropine toxicity in the present study (1.8%) was considerably lower than conventional regimen used in previous studies. Conclusion:Using the new protocol, lower rate of atropine toxicity developed in victims. Hence, the new protocol appears to be safer and its effectiveness should be further evaluated in case control studies in Bangladesh. How to cite this article: Ahmed AS, Basher A, Amin MR, Faiz MA. Effect of Intensive Atropine Doses (Rapid Incremental Loading and Titration) for Management of Organophosphorus Pesticide Poisoning: a Case Series. Asia Pac J Med Toxicol 2014;3:23-6.

Background: The effective therapeutic dose of pralidoxime methylsulphate for organophosphate (OP) poisoning is necessary to be clarified. This study was designed to comparatively assess the blood level of pralidoxime (BPL) and clinical outcomes in OP poisoned patients treated with intermittent dosing and patients treated with continuous infusion. Methods: This was a prospective, open labelled, cross-sectional, nonrandomized observational study which was done from 2009 to 2012 in a tertiary care hospital in Manipal, India. A high-performance liquid chromatography (HPLC) method with prominence diode array (PDA) detector was developed to measure BPL. Patients were categorized into study and control groups. Patients in study group were divided into 3 subgroups as they were treated with (a) intermittent pralidoxime dosing (1 g/q8h) or (b) continuous pralidoxime infusion (500 mg/h) or (c) continuous pralidoxime infusion (1 g/h). Patients who were not treated with pralidoxime were considered as the control group. The level of acetylcholinesterase (AChE) was measured before and pralidoxime therapy. Results: The developed HPLC method was linear over the range of 0.5-50 µg/mL and the correlation coefficient was found to be greater than 0.99. The median (IQR) of BPL in intermittent dosing (4.63 (5.26)) was comparatively lower than patients treated with continuous infusion. The highest BPL was maintained in 1 g/h group with median (IQR) serum level of 38.86 (16.75). The reactivation rate of AChE was higher in continuous infusion groups compared to intermittent dosing. Comparison of AChE before and after pralidoxime therapy showed that higher BPL was associated with greater reactivation of AChE. Conclusion: HPLC can be used as alternative method for measurement of pralidoxime level in blood. Continuous infusion of pralidoxime maintained a steady higher blood concentration compared to intermittent dosing with vast fluctuations. The reactivation rate of AChE was higher in continuous infusion compared to intermittent dosing. Hence, continuous infusion of pralidoxime can more rapidly recover the OP poisoned patients with less morbidity. How to cite this article: Thunga G, Pandey S, Nair S, Mylapuri R, Vidyasagar S, Kunhikatta V, et al. Comparative Study of Continuous Pralidoxime Infusion versus Intermittent Dosing: Application of High-Performance Liquid Chromatography Method on Serum of Organophosphate Poisoned Patients. Asia Pac J Med Toxicol 2013;2:105-10.

Background: Deliberate self-harm (DSH) is a global problem which has steadily increased over the past few years in developing countries and has become as one of the major causes of morbidity and mortality in these countries. The aim of this prospective study was to analyze the prevalence of organophosphate poisoning among other acute DSH cases admitted to the medical ward at Batticaloa Teaching Hospital, Sri Lanka. We report the socio-demographic, and outcome of organophosphate poisoning. Method: The prospective study comprises of 121 cases of acute poisoning admitted at Batticaloa Teaching Hospital (BTH), Sri Lanka. This study was conducted for a period of three months from April 12 through July 12, 2017. Results: Among the subjects, 119 (98.34%) cases had intentional poisoning and only two cases (1.65%) accidental poisoning. Poisoning with organophosphate compounds (OP) 23 (19%) was the second leading type. There were 13 (56.5%) males and 10 (43.5%) females. Most of the patients were under the age group of 20-29 years old. 21 cases lived in rural areas and 2 in urban areas. Out of 23 patients, there were 2 (8.7%) deaths, 18 (78.3%) were discharged without any complications. Conclusion: DSH in Sri Lanka is reported to be associated with interpersonal conflict, short premeditation, as well as alcohol misuse among males. [ABSTRACT FROM AUTHOR]

Organophosphate (OP) compounds are frequently used agorchemicals for deliberate self-harm in some parts of the world resulting in high mortality and morbidity. Pralidoxime (2PAM) is the most widely used and trialed oxime for treatment of OP poisoning. There have been variations over the results of trials using 2PAM for OP poisoning. 2PAM therapy has led to favorable outcomes in some studies, whereas it has been associated with unfavorable outcomes or without benefit in the others. Why 2PAM works in some trials and why it does not in the others, has been a key question for medical toxicologists with no definite answer. In this systematic review, we sought to investigate possibilities of the variations in the results of different studies conducted on the effectiveness of 2PAM therapy for OP poisoning and we tried to provide solutions for future studies. [ABSTRACT FROM AUTHOR]

Background: Organophosphates are commercially available agrochemicals for pest control, but may be abused for deliberate self-poisoning. We report a case of suicidal ingestion of dimethoate, a moderately toxic organophosphate insecticide, which can cause refractory hemodynamic instability, and the successful use of methylene blue (MB) for counteracting this complication. Case Presentation: An unconscious 47-year-old man was referred to emergency department with history of dimethoate ingestion. He rapidly developed hypotension that was refractory to antidotes, resuscitative hydration and multiple vasopressors including norepinephrine, epinephrine and vasopressin. Pulmonary artery catheterization revealed high cardiac output and low peripheral vascular resistance consistent with distributive shock, a complication previously reported in the setting of acute dimethoate toxicity. MB was initiated for the patient and improved hemodynamic status (increased MAP, systolic and diastolic blood pressures) and seized vasopressor requirement. Laboratory tests revealed that on-admission plasma cholinesterase level and dimethoate serum level were 2247 U and 56 µg/mL, respectively. The patient required 2 week ICU course with eventual tracheotomy for ventilation and later transferred to step down level of care. Discussion: Although MB therapy has been reported to be useful in managing sepsis-induced hypotension, there has been no similar report of its use in organophosphate poisoning. Our patient had no objective evidence for sepsis, and MB infusion improved hemodynamics within 6 hours and the effect was continued even after discontinuation of the therapy. The underlying mechanism of dimethoate-induced hypotension might be related to increase in nitric oxide (NO) formation. MB is effective to inhibit NO synthase. Conclusion: MB treatment was effective to reverse hypotension and restore hemodynamic instability caused by dimethoate poisoning. This index case may pave way to further investigation of MB therapy for OP-induced hemodynamic instabilities. [ABSTRACT FROM AUTHOR]

Organophosphate (OP) poisoning is one of the most common causes of poisoning in developing countries especially in Southeastern Asia. Poisoning with phosphorus-containing organic chemicals or OP compounds can be managed with antidotes like oximes which are potential reactivators of acetylcholinesterase (AChE). The efficacy of oxime therapy in OP poisoned patients mainly depends upon various factors such as different dose plans, infusion rate of oximes, genetic differences of patients, type of oxime used and chemical nature of the OP compound ingested. Studies on pralidoxime kinetics in OP poisoned patients have shown that reactivation of AChE depends on the plasma concentration of oximes as well as OP compounds. The plasma concentration of oximes mainly depends on the dose plan from intermittent injection to continuous infusion after a loading dose. The incontrovertible fact is that the intermittent dosing of oximes results in deep troughs in blood pralidoxime/oxime levels (BPL) whereas continuous infusion of oximes maintains steady state plasma concentrations. Many published literature also highlighted pralidoxime via continuous infusion results in better outcomes with minimum fluctuation in BPL compared to intermittent dosing. At therapeutic doses, adverse effects of oximes are reported to be minimal. But high BPL is associated with some common adverse effects including dizziness, blurred vision and diastolic hypertension. Considering all the facts, it is important to note that kinetic studies of oximes are useful not only in deciding the dose regimen, but also in predicting the possible side-effects. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular effects of acute organophosphate (OP) poisoning are common. This study was aimed to assess the cardiovascular effects of OP poisoned patients in Nepal. Methods: This was a prospective hospital-based cross-sectional study of 115 acute OP poisoned patients presenting in emergency department of a tertiary care teaching hospital of central Nepal during November 2008 to October 2011. Cardiovascular manifestations were assessed by physical examination and electrocardiogram (ECG). All data including demographic features, clinical findings and outcomes were entered into a pre-structured proforma. Results: A total of 115 OP poisoned patients were studied. Mean age of the patients was 29.8±13.9 years. Fifty-seven patients (49.6%) developed cardiac effects that all had sinus tachycardia. Sinus bradycardia was observed in 3 patients (2.61%). Hypertension was detected in 23 patients (20%) and pulmonary edema developed in 24 patients (20.9%). The most common ECG abnormalities recorded were prolonged QTc in 21 patients (18.26%) and ventricular extrasystole in 14 patients (12.2%). Five patients developed polymorphic ventricular tachycardia (VT) and 3 patients developed ventricular fibrillation (VF) which could not be reverted back despite adequate treatments and led to death (mortality rate: 6.9%). Conclusion: Cardiac effects of OP poisoning can be life-threatening. Prompt diagnosis, early supportive and definitive therapies with atropine and oximes along with vigilant monitoring of the patients for prominent cardiac effects such as QT prolongation, VT or VF during hospital stay can definitely save lives of the victims. [ABSTRACT FROM AUTHOR]

Background: It is becoming apparent that although inhibition of cholinesterase plays a key role in organophosphate (OP) toxicity, other factors are also important. One of the contributing factors for severity of OP poisoning is electrolyte imbalances such as hypokalemia. This study was aimed at evaluating the value of hypokalemia in association with plasma cholinesterase (PChE) levels in predicting morbidity and mortality of acute OP poisoning. Methods: In this cross sectional study patients with definitive diagnosis of OP poisoning were enrolled. Pre-interventional clinical features were observed and noted with severity assessment as per Proudfoot classification, along with measurement of serum potassium ion ([K+]) concentration and PChE level. Results: Fifty OP poisoned patients (33 men, 17 women) were enrolled with median age of 27.1 years. The most common clinical manifestation was congested conjunctiva (82%) followed by miosis (78%) and bronchorrhea (78%). A total of 21 cases presented with one or more severe clinical features according to Proudfoot classification. Among them, 61.9% of cases (13 out of 21) developed hypokalemia. Muscle weakness or fasciculation developed with mean serum [K+] of 3.31 ± 0.11. Ventilatory support was required at the mean serum [K+] of 3.27 ± 0.10 mmol/L. Fatality was noted when the mean serum [K+] reduced to 2.90 ± 0.06 mmol/L. Correlation of the clinical effects and serum [K+] was significant (P < 0.001). In addition, muscle weakness, fasciculation, convulsion and respiratory distress were associated with marked suppression of PChE (>75%). Death was mostly observed among patients who had respiratory distress associated with hypokalemia and grossly reduced PChE. Conclusion: For severe clinical features of OP poisoning, serum [K+] and PC hE level are greatly reduced. Hence, these biochemical findings can be proposed as OP poisoning predictive markers. Clinicians and medical toxicologists should consider hypokalemia associated with reduced PChE level as alarming signs of poor prognosis in OP poisoned patients. [ABSTRACT FROM AUTHOR]

Background: Acute poisoning with organophosphorus (OP) pesticides is a common method of suicide and entails considerable mortality in Bangladesh. The objective of this study was to evaluate the effects and outcomes of a protocol for treatment of OP poisoning that included titrated incremental atropine as loading dose and slow infusion for maintenance. Methods: In this prospective descriptive case series, definitive OP poisoned patients were enrolled in an adult medicine unit of Dhaka Medical College Hospital from April 2006 to April 2007. Clinical examinations were done as soon as the patient entered the ward. Patient's demographics, comorbid conditions and the occurrence of specific clinical outcomes including death, need for assisted ventilation and clinical complications were recorded. The patients were treated according to the protocol. Results: A total of 56 patients were enrolled over the study period. The median age of the study population was 22.5 years. Most patients were men (67.8%). The most common clinical presentation was miosis (58.9%). In total, 11 patients died (19.6%). Intermediate syndrome developed in 12 patients (21.4%) and 6 of them died. Assisted ventilation was required in 16 cases (28.5). Patients with diastolic blood pressure ≤ 70 mmHg and/or GCS ≤ 10 were significantly less likely to survive (P = 0.02, 0.006, respectively). Moreover, early respiratory failure (P < 0.001) and the need for assisted ventilation (P < 0.001) were significantly higher among deceased cases. The mortality rate in this study was similar to previous studies. The frequency of atropine toxicity in the present study (1.8%) was considerably lower than conventional regimen used in previous studies. Conclusion: Using the new protocol, lower rate of atropine toxicity developed in victims. Hence, the new protocol appears to be safer and its effectiveness should be further evaluated in case control studies in Bangladesh. [ABSTRACT FROM AUTHOR]

Background: The role and proper dose of pralidoxime in the treatment of Organophosphorus (OP) compounds poisoning is an unresolved issue .This study was designed to compare the regimen recommended by the World Health Organization (WHO) with the commonly used standard regimen of pralidoxime. Methods: This was a randomized open labeled prospective study on OP poisoned patients admitted to JSS Hospital, Mysore, India during November 2009 to January 2012. WHO regimen of 2 g pralidoxime bolus followed by 8mg/kg/h infusion (study group) compared with standard regimen of 2 g pralidoxime bolus followed by 1g 6 hourly (control group). Results: In total, 82 patients were studied. Thirty-seven patients were randomized into the study group and 45 patients to the control group. All patients had moderate clinical severity. Although fewer patients in the study group required mechanical ventilation in comparison to the controls (12 vs. 22), the difference was not significant (P = 0.13). The death rate was lower in the study group though the difference was not also significant (P = 0.17). Mean (SD) duration of mechanical ventilation in the study group was significantly lower than controls (4.1 (1.6) vs. 6.6 (1.7) days; P = 0.01). Mean dosage of atropine administered was significantly lower in the study group compared to controls (345.0 (90.6) vs. 933.1 (162.3) mg; P = 0.001). Furthermore, 15 controls (33.3%) developed intermediate syndrome whereas no patient (0%) in the study group had such complication, which showed a significant difference (P< 0.001). Conclusion: A dose regimen of pralidoxime consisting of 2 g pralidoxime bolus followed by 8mg/kg/h infusion reduces morbidity and mortality in moderate cases of OP poisoning. The WHO dose regimen had significantly better outcomes compared to the standard dose regimen. [ABSTRACT FROM AUTHOR]