Extrapyramidal syndrome as a delayed and reversible complication of acute dichlorvos organophosphate poisoning.

We describe 4 cases of delayed extrapyramidal disorder following acute dichlorvos poisonings. All patients were seriously poisoned since all exhibited profound coma and respiratory failure, and they were all tracheally intubated and mechanically ventilated. On admission, plasma cholinesterase activity was greaty decreased, < 10 micromol/ml/h at 37 C in all patients (< 10% of normal for our laboratory). Extrapyramidal symptoms occurred between 5 and 15 d and were characterized by dystonia of arms and legs, resting tremor, cogwheel rigidity, and hypereflexia. With bromocriptine therapy the features of extrapyramidal syndrome disappeared progressively with complete recovery in all patients. Our observations suggest a delayed extrapyramidal syndrome should be taken into account during the course of acute dichlorvos organophosphate poisonings.