An unusual case of fatal accidental paraquat poisoning

A Forensic Case of Suicide Ingestion of Paraquat Herbicide: New Histological Insights and Revision of the Literature

ABSTRACT

Paraquat (PQ) is one of the most widely used herbicides in the world, and poisoning is generally associated with accidental, suicidal, or homicidal events. Therefore, in the forensic context, PQ could be in various ways involved as a possible cause of death of a subject. However, even though its systemic toxicity is known, the biological effects exerted on individual viscera have been explored only to some extent, especially in case of victim's survival. Therefore, a case concerning a suicidal ingestion of PQ with survival of 3 days was deemed of interest. Clinical toxicological analyses confirmed acute PQ intoxication, and after the death of the victim, an autopsy was performed showing local and systemic signs of ingestion of a caustic substance. Histologic examination revealed marked cellular damage to the major viscera, particularly the gastroesophageal tract, liver, kidneys, and lungs, with initial alveolar fibrosis noted despite the patient's short survival. This finding represents a new element in the context of PQ lung injury, as it has not been previously documented in the literature. Thus, histological findings in lethal intoxications after survival can reveal specific peculiarities still unknown and, therefore, assume transversal relevance not only at forensic but also clinical level.

Paraquat Exposure of Pregnant Women and Neonates in Agricultural Areas in Thailand

This study aimed to assess paraquat concentrations in the urine of women at 28 weeks of pregnancy, delivery and 2 months postpartum and in the meconium of neonates. In all, 79 pregnant women were recruited from three hospitals located in agricultural areas in Thailand. The subjects were interviewed about personal characteristics, agricultural activities and pesticide use patterns. Paraquat was analyzed in urine and meconium using high performance liquid chromatography equipped with a fluorescence detector. The geometric mean (GSD) of urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum were 2.04 (4.22), 2.06 (5.04) and 2.42 (5.33) ng/mL, respectively. The urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum between agriculturist and non-agriculturist were not significantly different (p = 0.632, p = 0.915, p = 0.57, respectively). The geometric mean (GSD) of paraquat concentration in the meconium was 33.31 (4.59) ng/g. The factors predicting paraquat exposures among pregnant women and neonates included working outside, living near farmland, having family members who work on a farm, drinking well water and using herbicides or paraquat.

Pneumomediastinum predicts early mortality in acute paraquat poisoning

CONTEXT

In paraquat (PQ) poisoning, death often occurs after the appearance of pneumomediastinum (PM). However, the clinical features and eventual outcome of PM in PQ intoxication remains unclear.

OBJECTIVE

We aimed to characterize PM following PQ poisoning and its prognostic value for predicting mortality.

MATERIALS AND METHODS

Enrolled PQ-poisoned patients (n = 75) were divided into two groups according to whether PM could be detected by chest computed tomography or not. The study outcomes included 5- and 90-day death after intoxication. Survival curves were derived using the Kaplan-Meier method, and mortality risk factors were analyzed by forward stepwise Cox regression analysis.

RESULTS

PM was documented in 21.3% of the patients (16/75); in 13 of them PM set in within 3 days of PQ ingestion. 15 patients died within 3 days of appearance of PM. Compared with patients without PM, those with PM were younger (P = 0.011), and had higher scores of Acute Physiology and Chronic Health Evaluation (P < 0.001) and Sequential Organ Failure Assessment (P = 0.003). In addition, patients with PM had a higher incidence of acute renal failure (P = 0.001), toxic hepatitis (P = 0.008), and respiratory insufficiency (P = 0.003). PM predicted an increased risk of 90-day death (93.8% of patients with PM vs. 40.7% among those without PM; hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.0-5.6; P = 0.045), and increased risk of 5-day death (81.3% vs. 27.1%; HR, 3.2; 95% CI, 1.2-8.1; P = 0.017).

DISCUSSION AND CONCLUSION

Early PM, occurring within 8 days, is a specific predictor of mortality in PQ poisoning.

Paraquat poisoning in pediatric patients

OBJECTIVE

This observational study examined the outcome of Taiwanese pediatric patients with paraquat poisoning and compared these data with the published data on paraquat poisonings from other international poisoning centers.

METHODS

We performed a retrospective study on children with acute paraquat poisoning that were admitted to the Chang Gung Memorial Hospital during a period of 10 years (2000-2010). Of the 193 paraquat poisoning patients, only 6 were children.

RESULTS

The mean age was 8.85 ± 5.55 (1-15.6) years. Younger patients had accidentally swallowed paraquat, whereas older patients had intentionally ingested paraquat. Most patients were referred within a relatively short period (0.5-2.0 hours). Paraquat poisoning was associated with high morbidity and often resulted in severe complications, including acute respiratory distress syndrome and multiple-organ failure. The complications included shock (50.0%), hypoxemia (33.3%), respiratory failure (33.3%), nausea/vomiting (16.7%), abdominal pain (33.3%), hepatitis (66.7%), gastrointestinal tract bleeding (33.3%), acute renal failure (33.3%), and seizures (16.7%). Patients were treated aggressively with a standard detoxification protocol consisting of gastric lavage, active charcoal, charcoal hemoperfusion, and cyclophosphamide and steroid pulse therapies. Secondary bacterial infections were common after hospitalization and included sepsis (33.3%), pneumonia (33.3%), and urinary tract infection (50.0%). In the end, 2 patients (33.3%) died from multiple-organ failure, despite intensive resuscitation.

CONCLUSIONS

Our data (mortality rate, 33.3%) are comparable to the data of other published reports from other international poison centers. Evidently, a prompt diagnosis of paraquat poisoning and an immediate institution of a detoxification protocol is a prerequisite for a favorable outcome.

Homicide by paraquat poisoning

We report on two cases of homicide by paraquat poisoning. Both cases occurred in children and the common clinical presentations were gastrointestinal ulceration and acute respiratory distress, with pneumomediastinitis. Bullous emphysema was a common autopsy finding. Physicians and pathologists should be aware of these findings, for they are almost diagnostic of acute paraquat poisoning.