Intermediate syndrome in organophosphate poisoning: case series

Abstract

Acute organophosphate insecticide poisoning is very common in developing countries and the mortality is high because of lack of adequate hospitalization, inadequate atropinization and undiagnosed intermediate syndrome which occur within 24-96 hour after the ingestion of poison. Acute organophosphate poisoning can manifest 3 different phases of toxic effects, namely, acute cholinergic crisis, intermediate syndrome (IMS), and delayed neuropathy. Among them, IMS has been considered as a major contributing factor of organophosphate-related morbidity and mortality because of its frequent occurrence and probable consequence of respiratory failure. The clinical manifestations of IMS typically occur within 24 to 96 hours, affecting conscious patients without cholinergic signs, and involve the muscles of respiration, proximal limb muscles, neck flexors, and muscles innervated by motor cranial nerves. With appropriate therapy that commonly includes artificial respiration; complete recovery develops 5-18 days later. The treatment of IMS is mainly supportive. Nevertheless, because IMS generally concurs with severe organophosphate toxicity and persistent inhibition of acetylcholinesterase, early aggressive decontamination, appropriate antidotal therapy, and prompt institution of ventilatory support should be helpful in ameliorating the magnitude and/or the incidence of IMS. The prognosis of IMS, however, is likely to be favorable if respiratory failure can be promptly recognized and treated accordingly.