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

AChE reactivation in precision-cut lung slices following organophosphorus compound poisoning

Precision-cut lung slices (PCLS) are a suitable model for analyzing the acetylcholinesterase (AChE) activity and subsequent effects after exposure to organophosphorus (OP) compounds. In this study, the AChE activity was determined in intact PCLS for the first time. Since the current standard therapy for OP poisoning (atropine + oxime + benzodiazepine) lacks efficiency, reliable models to study novel therapeutic substances are needed. Models should depict pathophysiological mechanisms and help to evaluate the beneficial effects of new therapeutics. Here PCLS were exposed to three organophosphorus nerve agents (OPNAs): sarin (GB), cyclosarin (GF), and VX. They were then treated with three reactivators: HI-6, obidoxime (OBI), and a non-oxime (NOX-6). The endpoints investigated in this study were the AChE activity and the airway area (AA) change. OPNA exposure led to very low residual AChE activities. Depending on the reactivator properties different AChE reactivation results were measured. GB-inhibited PCLS-AChE was reactivated best, followed by VX and GF. To substantiate these findings and to understand the connection between the molecular and the functional levels in a more profound way the results were correlated to the AA changes. These investigations underline the importance of reactivator use and point to the possibilities for future improvements in the treatment of OPNA-exposed victims.

A-agents, misleadingly known as "Novichoks": a narrative review

"Novichok" refers to a new group of nerve agents called the A-series agents. Their existence came to light in 2018 after incidents in the UK and again in 2020 in Russia. They are unique organophosphorus-based compounds developed during the Cold War in a program called Foliant in the USSR. This review is based on original chemical entities from Mirzayanov's memoirs published in 2008. Due to classified research, a considerable debate arose about their structures, and hence, various structural moieties were speculated. For this reason, the scientific literature is highly incomplete and, in some cases, contradictory. This review critically assesses the information published to date on this class of compounds. The scope of this work is to summarize all the available and relevant information, including the physicochemical properties, chemical synthesis, mechanism of action, toxicity, pharmacokinetics, and medical countermeasures used to date. The environmental stability of A-series agents, the lack of environmentally safe decontamination, their high toxicity, and the scarcity of information on post-contamination treatment pose a challenge for managing possible incidents.

Organophosphate insecticide poisoning with monocrotophos-induced fabricated illness in a 7-year-old girl with refractory seizures over a 4-year period

Munchausen syndrome by proxy is a form of abuse in which an adult, usually the mother, deceives health workers by exaggerating, falsifying or directly inducing psychological or physical symptoms in the child victim for psychological gratification. In 2013, the American Academy of Pediatrics coined the term 'caregiver-fabricated illness in a child' to describe this form of child abuse. A 7-year-old girl had many encounters with health workers over a period of 4 years and presented with evolving clinical features including refractory seizures and red urine for which she was followed up as a case of acute intermittent porphyria. She was later discovered to be the victim of chronic monocrotophos organophosphate poisoning by her mother. If all medical staff who manage children are to avoid becoming inadvertent participants in medical child abuse, this case report is an important reminder that a high index of suspicion is warranted in cases which present a diagnostic dilemma and who respond unexpectedly to treatment.Abbreviations AIP: Acute intermittent porphyria; APSAC: American Professional Society on the Abuse of Children; ASM: anti-seizure medication; CFIC: caregiver-fabricated illness in a child; CT: computed tomography: DVT: deep vein thrombosis; EEG: electroencephalogram: ESR: erythrocyte sedimentation rate; HDW: high-dependency ward; ICU: intensive care unit; LFT: liver function test; MBP: Munchausen syndrome by proxy; NICU: neonatal intensive care unit; RFT: renal function test; TB: Tuberculosis; UTH-CH: University Teaching Hospitals Children's Hospital.

Refractory and Super-Refractory Status Epilepticus in Nerve Agent-Poisoned Rats Following Application of Standard Clinical Treatment Guidelines

Nerve agents (NAs) induce a severe cholinergic crisis that can lead to status epilepticus (SE). Current guidelines for treatment of NA-induced SE only include prehospital benzodiazepines, which may not fully resolve this life-threatening condition. This study examined the efficacy of general clinical protocols for treatment of SE in the specific context of NA poisoning in adult male rats. Treatment with both intramuscular and intravenous benzodiazepines was entirely insufficient to control SE. Second line intervention with valproate (VPA) initially terminated SE in 35% of rats, but seizures always returned. Phenobarbital (PHB) was more effective, with SE terminating in 56% of rats and 19% of rats remaining seizure-free for at least 24 h. The majority of rats demonstrated refractory SE (RSE) and required treatment with a continuous third-line anesthetic. Both ketamine (KET) and propofol (PRO) led to high levels of mortality, and nearly all rats on these therapies had breakthrough seizure activity, demonstrating super-refractory SE (SRSE). For the small subset of rats in which SE was fully resolved, significant improvements over controls were observed in recovery metrics, behavioral assays, and brain pathology. Together these data suggest that NA-induced SE is particularly severe, but aggressive treatment in the intensive care setting can lead to positive functional outcomes for casualties.

Successful management of a kitten with chlorpyrifos and cypermethrin toxicosis with pralidoxime and atropine

CASE SUMMARY

Organophosphates and pyrethroids have been widely used as agricultural and domestic insecticides. This case report describes a 3-month-old free-roaming female kitten, weighing 930 g, that developed hypersalivation, hypothermia, dyspnoea due to increased bronchial secretion, bradycardia, miosis and neurological signs, including restlessness, ataxia, disorientation, apparent hallucination, muscle twitching and seizures within 6 h of accidental ingestion of an insecticide containing chlorpyrifos (500 g/l) and cypermethrin (50 g/l). The kitten was treated empirically with intramuscular atropine and dexamethasone, and rectal diazepam. The history of insecticide exposure was obtained after 6 h of treatment and intramuscular 2-pyridine aldoxime methochloride (pralidoxime [2-PAM]) and atropine therapy was started 2 h later. Recovery was complicated by suspected aspiration, but there were no sequelae from the insecticide exposure and by 7 days post-ingestion the kitten was normal and playful.

RELEVANCE AND NOVEL INFORMATION

To the best of our knowledge, this is the first report of successful management of chlorpyrifos and cypermethrin toxicosis in a cat in Bangladesh. This case report suggests that 2-PAM followed by atropine and other supportive therapy may be an effective strategy to manage a cat poisoned by chlorpyrifos and cypermethrin; however, expanded clinical trials are needed.

Role of penehyclidine in acute organophosphorus pesticide poisoning

BACKGROUND

Penehyclidine is a newly developed anticholinergic agent. We aimed to investigate the role of penehyclidine in acute organophosphorus pesticide poisoning (OP) patients.

METHODS

We searched the Pubmed, Cochrane library, EMBASE, Chinese National Knowledge Infrastructure (CNKI), Chinese Biomedical literature (CBM) and Wanfang databases. Randomized controlled trials (RCTs) recruiting acute OP patients were identified for meta-analysis. Main outcomes included cure rate, mortality rate, time to atropinization, time to 60% normal acetylcholinesterase (AchE) level, rate of intermediate syndrome (IMS) and rate of adverse drug reactions (ADR).

RESULTS

Sixteen RCTs involving 1,334 patients were identified. Compared with the atropine- or penehyclidine-alone groups, atropine combined with penehyclidine significantly increased the cure rate (penehyclidine+atropine vs. atropine, 0.97 vs. 0.86, RR 1.13, 95% CI [1.07-1.19]; penehyclidine+atropine vs. penehyclidine, 0.93 vs. 0.80, RR 1.08, 95% CI [1.01-1.15]) and reduced the mortality rate (penehyclidine+atropine vs. atropine, 0.015 vs. 0.11, RR 0.17, 95% CI [0.06-0.49]; penehyclidine+atropine vs. penehyclidine, 0.13 vs. 0.08, RR 0.23, 95% CI [0.04-1.28]). Atropine combined with penehyclidine in OP patients also helped reduce the time to atropinization and AchE recovery, the rate of IMS and the rate of ADR. Compared with a single dose of atropine, a single dose of penehyclidine also significantly elevated the cure rate, reduced times to atropinization, AchE recovery, and rate of IMS.

CONCLUSION

Atropine combined with penehyclidine benefits OP patients by enhancing the cure rate, mortality rate, time to atropinization, AchE recovery, IMS rate, total ADR and duration of hospitalization. Penehyclidine combined with atropine is likely a better initial therapy for OP patients than atropine alone.

Pediatric Thermoregulation: Considerations in the Face of Global Climate Change

Predicted global climate change, including rising average temperatures, increasing airborne pollution, and ultraviolet radiation exposure, presents multiple environmental stressors contributing to increased morbidity and mortality. Extreme temperatures and more frequent and severe heat events will increase the risk of heat-related illness and associated complications in vulnerable populations, including infants and children. Historically, children have been viewed to possess inferior thermoregulatory capabilities, owing to lower sweat rates and higher core temperature responses compared to adults. Accumulating evidence counters this notion, with limited child-adult differences in thermoregulation evident during mild and moderate heat exposure, with increased risk of heat illness only at environmental extremes. In the context of predicted global climate change, extreme environmental temperatures will be encountered more frequently, placing children at increased risk. Thermoregulatory and overall physiological strain in high temperatures may be further exacerbated by exposure to/presence of physiological and environmental stressors including pollution, ultraviolet radiation, obesity, diabetes, associated comorbidities, and polypharmacy that are more commonly occurring at younger ages. The aim of this review is to revisit fundamental differences in child-adult thermoregulation in the face of these multifaceted climate challenges, address emerging concerns, and emphasize risk reduction strategies for the health and performance of children in the heat.

Tonic inhibition of brown adipose tissue sympathetic nerve activity via muscarinic acetylcholine receptors in the rostral raphe pallidus

KEY POINTS

A tonically active, muscarinic cholinergic inhibition of rostral raphe pallidus (rRPa) neurons influences thermogenesis of brown adipose tissue (BAT) independent of ambient temperature conditions. The tonically active cholinergic input to rRPa originates caudal to the hypothalamus. Muscarinic acetylcholine receptor (mAChR) activation in rRPa contributes to the inhibition of BAT sympathetic nerve activity (SNA) evoked by activation of neurons in the rostral ventrolateral medulla (RVLM). The RVLM is not the sole source of the muscarinic cholinergic input to rRPa. Activation of GABA receptors in rRPa does not mediate the cholinergic inhibition of BAT SNA.

ABSTRACT

We sought to determine if body temperature and energy expenditure are influenced by a cholinergic input to neurons in the rostral raphe pallidus (rRPa), the site of sympathetic premotor neurons controlling thermogenesis of brown adipose tissue (BAT). Nanoinjections of the muscarinic acetylcholine receptor (mAChR) agonist, oxotremorine, or the cholinesterase inhibitor, neostigmine (NEOS), in the rRPa of anaesthetized rats decreased cold-evoked BAT sympathetic nerve activity (SNA, nadirs: -72 and -95%), BAT temperature (Tbat, -0.5 and -0.6°C), expired CO₂ (Exp. CO₂ , -0.3 and -0.5%) and heart rate (HR, -22 and -41 bpm). NEOS into rRPa reversed the increase in BAT SNA evoked by blockade of GABA receptors in rRPa. Nanoinjections of the mAChR antagonist, scopolamine (SCOP), in the rRPa of warm rats increased BAT SNA (peak: +1087%), Tbat (+1.8°C), Exp. CO₂ (+0.7%), core temperature (Tcore, +0.5°C) and HR (+54 bpm). SCOP nanoinjections in rRPa produced similar activations of BAT during cold exposure, following a brain transection caudal to the hypothalamus, and during the blockade of glutamate receptors in rRPa. We conclude that a tonically active cholinergic input to the rRPa inhibits BAT SNA via activation of local mAChR. The inhibition of BAT SNA mediated by mAChR in rRPa does not depend on activation of GABA receptors in rRPa. The increase in BAT SNA following mAChR blockade in rRPa does not depend on the activity of neurons in the hypothalamus or on glutamate receptor activation in rRPa.

Outbreak of Sudden Death with Acute Encephalitis Syndrome Among Children Associated with Exposure to Lychee Orchards in Northern Bangladesh, 2012

Recurrent outbreaks of acute encephalitis syndrome (AES) among children in lychee growing areas in Asia highlight the need to better understand the etiology and the context. We conducted a mixed-methods study to identify risk factors for disease, and behaviors and practices around lychee cultivation in an AES outbreak community in northern Bangladesh in 2012. The outbreak affected 14 children; 13 died. The major symptoms included unconsciousness, convulsion, excessive sweating, and frothy discharge. The median time from illness onset to unconsciousness was 2.5 hours. The outbreak corresponded with lychee harvesting season. Multiple pesticides including some banned in Bangladesh were frequently used in the orchards. Visiting a lychee orchard within 24 hours before onset (age-adjusted odds ratio [aOR] = 11.6 [1.02–109.8]) and 3 days (aOR = 7.2 [1.4–37.6]), and family members working in a lychee orchard (aOR = 7.2 [1.7–29.4]) and visiting any garden while pesticides were being applied (aOR = 4.9 [1.0–19.4]) in 3 days preceding illness onset were associated with illness in nearby village analysis. In neighborhood analysis, visiting an orchard that used pesticides (aOR = 8.4 [1.4–49.9]) within 3 days preceding illness onset was associated with illness. Eating lychees was not associated with illness in the case–control study. The outbreak was linked to lychee orchard exposures where agrochemicals were routinely used, but not to consumption of lychees. Lack of acute specimens was a major limitation. Future studies should target collection of environmental and food samples, acute specimens, and rigorous assessment of community use of pesticides to determine etiology.

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.

Survey on Hypothermia and Hyperthermia in Poisoned Patients in a Unique Referral Hospital, Tehran, Iran

Background

Body temperature is a critical criterion of health. Drugs and a variety of poisons can affect body temperature in poisoned patients, causing hyperthermia and hyperpyrexia.

Objectives

Our previous study’s findings in patients poisoned with organophosphate led us to the goal of this study: obtaining the initial tympanic temperature in patients poisoned by a variety of toxins.

Materials and Methods

A cross-sectional study reviewed the records of poisoned patients who were admitted to the toxicological intensive care unit (TICU) at Loghman Hakim hospital poison center (LHHPC) from February 2014 to February 2015. The data collected included gender, age, type of poisoning, the season during which poisoning occurred, vital signs, initial tympanic temperature (first four hours), presence of seizures, white blood cell (WBC) count, creatinine phosphokinase (CPK), length of stay and patient outcome. We determined the mean (SD) for normally distributed continuous variables, the median and interquartile range for non-normally distributed continuous variables, and the absolute and relative frequency (%) for categorical variables. All were determined using SPSS version 16.

Results

Data were collected from 310 eligible patients. The mean patient age was 32.65 (with a standard deviation of 14.40). Of the patients in the study, 183 (59%) were male. Intentional poisoning in an attempted suicide was documented in 253 (81.6%) patients. The most prevalent poisoning agent was aluminum phosphate (18.70%), followed by methadone (10%) and opium (10%). Seventy percent of the patients (n = 217) were diagnosed and classified with fever or hyperthermia. A temperature ≥ 40°C was detected in just three cases. The highest mean temperature was found in patients poisoned with amphetamine, organophosphate and tramadol. Patients with alcohol and phenobarbital poisoning were included in the sample, but these patients were not diagnosed with hypothermia. WBC ≥ 10,000 cells/mL and CPK ≥ 975 IU/L were recorded in 57.7% and 13.2% of subjects, respectively.

Conclusions

Body temperature changes in human poisonings are a matter in need of special attention. A literature review did not reveal any controversy over hypothermia, but poisoning cases exhibit a variety of patterns of fever and hyperthermia. If there are no limits to the diagnosis of fever and hyperthermia, all cases with a poor prognosis which fail to respond to treatment could be categorized as drug-induced hyperthermia. Therefore, a different approach is needed for poisoning cases.

Severe oral and intravenous insecticide mixture poisoning with diabetic ketoacidosis: a case report

Background

The widespread use of pesticides in public health protection and agricultural pest control has caused severe environmental pollution and health hazards, especially in developing countries, including cases of severe acute and chronic human poisoning. Diabetic ketoacidosis is an uncommon manifestation of acute pesticide poisoning. Suicidal pesticide poisoning by injection is also an unusual way to take poison. We report a severe pesticide mixture poisoning case with diabetic ketoacidosis in an adult with improved outcome after supportive treatment and large doses of atropine.

Case presentation

A 30-year-old unmarried Moroccan Arab male with a previous history of active polysubstance abuse and behavior disorders had ingested and self injected intravenously into his forearm an unknown amount of a mixture of chlorpyrifos and cypermethrin. He developed muscarinic and nicotinic symptoms with hypothermia, inflammation in the site of the pesticide injection without necrosis. Red blood cell cholinesterase and plasma cholinesterase were very low (<10%). By day 3, the patient developed stroke with hypotension (80/50 mmHg) and tachycardia (143 pulses /min). Laboratory tests showed severe hyperglycemia (4.49 g/dL), hypokaliemia (2.4 mEq/L), glycosuria, ketonuria and low bicarbonate levels (12 mEq/L) with improvement after intensive medical treatment and treatment by atropine.

Conclusion

Suicidal poisonings with self-injection of insecticide were rarely reported but could be associated with severe local and systemic complications. The oxidative stress caused by pyrethroids and organophosphates poisoning could explain the occurrence of hyperglycemia and ketoacidosis.

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.