Pesticide exposure and poisoning in Brazil: Outcome severity, clinical manifestations and management of cases reported to a poison control center.

This work aimed to identify variables associated with increased risk of outcome severity as well as to describe clinical manifestations/symptoms and management of pesticide-related cases reported to a poison center in Brazil. An increased risk of more severe outcomes was observed when exposures occurred in rural areas, involved suicide attempts and moderately to extremely hazardous pesticides. Clinical manifestations with higher frequencies included vomiting, nausea, sialorrhea, headache, miosis and sweating. From the treatment initially applied to the patient, 51.91% encompassed gastric lavage, but this procedure was only recommended in 20.01% of cases by the CIATox. Identifying risk factors associated with poor outcome, describing clinical manifestations, and contrasting initial treatment measures adopted against those recommended by the Poison Center can help determine diagnosis, prognosis and ensure appropriate clinical interventions are used in cases of pesticide poisoning.

Sociodemographic characteristics and exposure patterns of pesticide-related cases reported to a poison service center in Brazil between 2012 and 2016.

Pesticide poisoning is a significant public health problem responsible for an estimated three million poisoning cases per year and more than 250,000 deaths, most of which occur in underdeveloped countries. We evaluated pesticide exposure cases reported to a toxicological service center in Brazil, between 2012 and 2016. There were 3211 cases of pesticide exposure, with a high prevalence in adults aged 20-39 years (41.2%). Attempted suicide was the leading cause of pesticide cases (48%). Occupational exposure to pesticides of agricultural use was more frequently observed among men. Accidental exposure and attempted suicide were more frequently observed in urban areas while occupational exposure was more prevalent in rural areas. A higher exposure rate was observed among men in counties with higher agricultural activities. Establishing prevalence and cause of pesticide exposure is important to provide subsidy for evidence-based interventions in the field.

Aerotoxic syndrome, discussion of possible diagnostic criteria.

Introduction: The term aerotoxic syndrome (ATS) was proposed 20 years ago to describe a constellation of symptoms reported by pilots and cabin crew following exposure to hydraulic fluids, engine oil, and pyrolysis products during flight. Hydraulic fluids and engine oil contain a large number of potentially toxic chemicals, including various organophosphate compounds (OPCs). However, ATS is not yet recognised as a valid diagnosis in aviation or general medicine, because the incidence and aetiology continues to be debated.Discussion: Early studies report findings from symptom surveys or cognitive assessments of small samples of self-selected aircrew, but objective measures of exposure were lacking. Over the last decade, researchers have used more sophisticated techniques to measure exposure, such as on board monitoring studies and biomarkers of exposure (e.g., reduced levels of serum butyrylcholinesterases [BChE]) and more sophisticated techniques to detect nervous system injuries such as fMRI and autoantibody testing. Consideration has also been given to inter-individual differences in the ability to metabolise certain chemical compounds as a result of genetic polymorphisms and exclusion of other potential causes of ill health.Conclusions: We discuss factors which suggest a diagnosis of probable ATS; recommend an assessment protocol which incorporates the aforementioned techniques; and propose diagnostic criteria for probable ATS, based on our previously reported findings in aircrew and the results of recent studies.

Anxiety and depression following cumulative low-level exposure to organophosphate pesticides.

Previous research suggests that individuals with a prior history of pesticide poisoning are at increased risk of psychiatric disorder (Freire and Koifman, 2013), but findings regarding the impact of cumulative low-level exposure are inconsistent. The aim of the current study was to investigate whether sheep farmers with a history of low-level exposure to organophosphate pesticides (1) report a higher level of psychological distress on subjective symptom questionnaires, compared to unexposed controls (2) also meet internationally agreed diagnostic criteria for a psychiatric disorder more often than unexposed controls. 127sheep farmers were evaluated and compared to 78 unexposed controls, matched in terms of gender, education, level of intelligence, working status and area of residence. Both self-report measures and structured clinical interviews were used to assess mental health. The exposed cohort reported significantly higher rates of anxiety and depression when self-report questionnaires were used to evaluate mood, even when stressful life events, demographic and physical health factors were taken into account. However, when diagnostic interviews were used to assess mood, this pattern only held true for anxiety.

Delayed cognitive and psychiatric symptoms following methyl iodide and manganese poisoning: Potential for misdiagnosis.

This paper describes two patients who were exposed to toxic substances in the workplace, but for whom diagnosis proved difficult, particularly in case 2. Case 1 was exposed to methyl iodide and case 2 to manganese. Poisoning was characterised by delayed onset of symptoms following exposure and symptom progression after cessation of exposure. The clinical consequences of exposure to these substances include cerebellar and Parkinsonian symptoms followed by the development of cognitive impairment and the late appearance of psychiatric disturbances. Both cases were evaluated by physicians with little training in toxicology. Apart from abnormal liver function in case 1 and decreased power, coordination and proprioception in case 2, results of most routine medical investigations were normal. Both cases were referred for MRI brain scan and neuropsychological assessment. Abnormalities were noted on MRI but reported as being absent initially in case 1and of unknown significance in case 2. There was evidence of cognitive impairment in both and personality change in case 1 of sufficient severity to prevent both cases from returning to work and to impact on family life. There is no antidote to methyl iodide or manganese poisoning. Successful treatment requires early diagnosis and cessation of exposure, but neurotoxic syndromes are difficult to diagnose when a time lag exists between exposure and symptom onset and there is no biomarker of exposure. These syndromes may initially be confused with other neurodegenerative conditions, infectious processes, and psychiatric disorders. Clinician's lack of familiarity with the potential toxicity of environmental and industrial chemicals can lead to misdiagnosis and mismanagement, and this lack of recognition can lead to continued exposure. These cases highlight the importance of taking a detailed occupational history in patients who present with atypical neurological symptoms.

Reflections on the process of using systematic review techniques to evaluate the literature regarding the neurotoxicity of low level exposure to organophosphate pesticides.

We undertook a systematic review (incorporating meta-analysis) of the literature concerning the neurotoxicity of cumulative low level occupational exposure to organophosphate pesticides, which was published online by the journal Critical Reviews in Toxicology in 2012. As far as we are aware, we were the first research team to attempt quantitative evaluation of study findings on this topic, using meta-analysis. We wish to encourage others to apply systematic review techniques in chemical risk assessment to reduce bias, increase transparency and better inform public policy. We thought it would be useful to share our experience of undertaking a systematic review in the hope of dispelling misconceptions about the complexity, time and resource issues involved along with the view that meta-analysis is meaningless when studies are not homogeneous. In this commentary paper we reflect on aspects of the process which were relatively straightforward; aspects which were more challenging; the advantages of using systematic review techniques; and the advantages and limitations of using statistical techniques such as meta-analysis in this context.

Neuropsychological and psychiatric functioning in sheep farmers exposed to low levels of organophosphate pesticides.

The study aim was to determine whether low level exposure to organophosphate pesticides (OPs) causes neuropsychological or psychiatric impairment. Methodological weaknesses of earlier studies were addressed by: recruiting participants who had retired on ill health grounds; excluding participants with a history of acute poisoning, medical or psychiatric conditions that might account for ill health; and exploring factors which may render some individuals more vulnerable to the effects of OPs than others. Performance on tests of cognition and mood of 127 exposed sheep farmers (67 working, 60 retired) was compared with 78 unexposed controls (38 working, 40 retired) and published test norms derived from a cross section of several thousand adults in the general population. Over 40% of the exposed cohort reported clinically significant levels of anxiety and depression compared to less than 23% of controls. Exposed subjects performed significantly worse than controls and standardisation samples on tests of memory, response speed, fine motor control, mental flexibility and strategy making, even after controlling for the effects of mood. The pattern was similar for both working and retired groups. The cognitive deficits identified cannot be attributed to mood disorder, malingering, a history of acute exposure or genetic vulnerability in terms of PON1(192) polymorphisms. Results suggest a relationship may exist between low level exposure to organophosphates and impaired neurobehavioural functioning and these findings have implications for working practice and for other occupational groups exposed to OPs such as aviation workers and Gulf War veterans.