Delayed neurotoxicity produced by an organophosphorus compound (Sumithion). A case report

A case of late-onset manifestation of organophosphorous insecticide poisoning is described. The patient was a 70-year-old female who ingested 40 ml Sumithion emulsion (50% fenitrothion). At first, no toxic symptoms were apparent. However, 48 h after ingestion certain signs became apparent. An impediment in consciousness was observed. Fasciculation and muscular weakness were noted, while plasma and urinary 4-nitro-3-methylphenol (NMC), the degradation product of Sumithion, reached a maximum. Neither atropine sulfate nor PAM (pyridine 2-aldoxime methiodine) were effective. For 3 weeks the patient required ventilatory support, and consequently her muscle strength and neurological status gradually recovered with falling NMC levels.