Acute carbamate and organochlorine toxicity causing convulsions in an agricultural pilot: a case report

Agricultural pilots are involved in a particularly hazardous occupation with a high occupational mortality rate. They face many risks, not least of which is exposure to the agricultural chemicals that they spray. Many accidents and illnesses have been reported previously in the literature, attributable to the acute and chronic effects of chemical exposure, most notably the organophosphate family of insecticides. There are few reports of post-crash exposure to carbamate and organochlorine insecticides. This report documents the case of a professional agricultural pilot who, following an emergency landing, was soaked with Methomyl (a carbamate) and Endosulfan (an organochlorine) leaking from his aircraft. He developed cholinergic symptoms within an hour of the accident, which settled spontaneously, but suffered a tonic-clonic seizure some 6 h later while in the hospital. The seizure was attributed to exposure to the organochlorine, however, subsequent EEG recordings demonstrated a non-specific epileptiform focus in the frontal lobes. The pilot made a full recovery and has remained seizure-free without treatment. The pathophysiology of carbamate and organochlorine poisoning is reviewed, and the differential diagnoses of seizures in this pilot discussed. The difficulty facing a licensing authority in determining the aeromedical disposition of a pilot who has suffered a provoked seizure is also highlighted.