Evidence of necrosis in human intercostal muscle following inhalation of an organophosphate insecticide.

Intercostal muscle samples obtained from autopsy of a 51 year old male, exposed to an organophosphate insecticide by inhalation, were analyzed for cholinesterase (ChE) activity and muscle fiber integrity. Muscle ChE activity, five days after exposure, was still reduced to 53% of control values. Histological analysis indicated the presence of muscle fibers with subsarcolemmal grouped granular basophilic inclusions and scattered necrotic fibers. Results indicate that acute organophosphate exposure through inhalation can lead to skeletal muscle fiber damage in humans, similar to results obtained by ingestion. Furthermore, the pathology is comparable to the histological alterations observed in rats following acute injection of organophosphates.