ABSTRACT
The neuromuscular transmission failure in acute anticholinesterases [e.g. organophosphorus compounds and carbamates] poisoning occurs because of inactivation of the enzyme acetylcholinesterase located in the neuromuscular junction, and is distinguished by single electrical stimulus induced repetitive responses and decrement response upon high rate repetitive nerve stimulation [RNS]. Oxime therapy with its action at different sites in the neuromuscular junction would alter the neuroelectrophysiological findings in acute anticholinesterases poisoning. The aim of this study is to evaluate the usefulness of RNS as a prognostic indicator of severity in acute anticholinesterase poisoning and the recovery process and its use as a guide for oxime therapy continuation or discontinuation. The study was conducted on 32 patients with acute organophosphorus poisoning admitted to the poison control center, Ain Shams University Hospitals during the period from January 2007 to June 2007. Patients were subdivided into group I [mild group n=6], group II [moderate group n=20], and group III [severe group n=6]. All the cases were clinically evaluated, pseudocholinesterase levels were estimated and RNS was done before and after oxime therapy. The patients were classified according to the decremental response into 3 categories, type 1 response [initial improvement and subsequent lack of improvement], type 2 responce [Initial improvement and subsequent normalization of neuromuscular transmission] and type 3 response [lack of improvement with initial dose of toxogonin]. RNS is a sensitive prognostic test which can be used as an early predictor of acute anticholinesterase poisoning for grading its severity, and assessment of obidoxime [Toxogonin] therapy. As therapeutic benefit of obidoxime is limited by its short duration of action, it is recommended to be administered for a longer period of time under neuroelectrophysiological guidance