[Intermediate syndrome after organophosphate poisoning despite continuous infusion of pralidoxime]

Acute organophosphate poisoning leads to a cholinergic crisis secondary to an acetylcholine rise, developed by an acetylcholinesterase inhibition. In some cases, after the resolution of the initial cholinergic signs and symptoms, an intermediate syndrome occurs, characterized by a delayed development of proximal and diaphragmatic muscle paralysis. We describe a case of a 67-year-old man who developed an intermediate syndrome after oxydemeton-metryl ingestion in a suicide attempt, despite a continuous pralidoxime infusion. Several hypotheses have been developed to explain the aetiology of this intermediate syndrome (neuromuscular junction dysfunction, inadequate poisoning treatment, late beginning of the oxime administration, etc). Intermediate syndrome manifestation will depend on the organophosphate's organism persistence and its chemical structure, and also on the time elapsed between the poisoning and the antidote administration.