Electrophysiological assessment of peripheral nerves and neuro-muscular junctions in patients following self-poisoning with paraquat

Paraquat is neurotoxic. We aimed to study the electrophysiological effects of peripheral nerves and neuromuscular junction (NMJ) in the survivors of paraquat poisoning. A cohort study was conducted on patients following paraquat poisoning. Controls were recruited. The assessments were performed around one and six weeks after the exposure. Motor nerve conduction velocity (MNCV), amplitude of compound muscle action potential (CMAP), sensory nerve conduction velocity (SNCV), F-wave studies, cardiovascular response to different stimuli, sympathetic skin response (SSR) studies, and exercise modified supramaximal slow repetitive stimulation (RNS) and electromyography (EMG) were performed. There were 28 (21 males) patients and 56 controls. The mean (SD) age of the patients and the controls were 29 (12) and 31 (11) years. Significant impairment at the first assessment in the SNCV of ulnar nerve, amplitude of ulnar nerve CMAP on distal stimulation, and F-wave occurrence in median, ulnar and tibial nerves; change of systolic blood pressure three minutes after standing and SSR amplitude ( vs controls) was observed. All parameters reverted to normal at six weeks after the exposure. There was electrophysiological evidence for somatic nerve, autonomic, and NMJ dysfunction following acute paraquat poisoning which was not seen at six weeks after the exposure.