Pyrethroid poisoning: Insecticide with mild human toxicity

Background

Pyrethroid insecticides are commonly used insecticides. This study was undertaken to characterize the clinical profile and outcome of deliberate self-harm (DSH) with type 1 and type 2 pyrethroids and identify factors associated with need for hospitalization.

Methods

This retrospective study was conducted in a tertiary care hospital in South India to study the clinical features, treatment, and outcome of patients with pyrethroid poisoning due to DSH. Patients were categorized as poisoning with type 1 or type 2 pyrethroid compounds. Factors associated with need for hospital admission was explored using bivariate and multivariate regression analysis and expressed as odds ratio (OR) with 95% confidence intervals (CIs).

Results

A total of 379 patients presented with pyrethroid poisoning; 202 (53.3%) patients were male. The median (interquartile range) age was 26 (22–33) years. Transfluthrin (n = 48, 58%) and cypermethrin (n = 149, 50%) were the most frequently implicated type 1 compounds and type 2 compounds, respectively. Of the 130 (34.3%) patients who were admitted, 13 (3.4%) patients required mechanical ventilation. All patients survived. On multivariate logistic regression analysis, ingestion of type 2 pyrethroids (OR: 2.55, 95%CI: 1.31–4.97), history of seizures (OR: 2.62, 95%CI 1.06-6.48), and treatment prior to presentation to the referral hospital (OR: 2.99, 95%CI: 1.87–4.74) were associated with the need for hospitalization.

Conclusion

A third of patients with pyrethroid poisoning require hospitalization. Type 2 pyrethroid poisoning is more frequent in clinical practice. Ingestion of type 2 pyrethroids, seizures, and need for pre-hospital treatment are associated with hospitalization.