Clinical and electrophysiological study of intermediate syndrome in patients with organophosphorous poisoning

Intermediate syndrome (IS) developed in 38 of 214 cases with organophosphorous compound poisoning (OPCP). Neck muscle weakness, motor cranial nerve palsy, respiratory muscle paralysis, proximal limb weakness were the chief neurological signs developed 16-120 hours after consumption of the insecticide. Two patients had pyramidal tract signs. Mean duration of IS was 9.26 (+/- 4.84) days. Electrophysiological study (EPS) was done in 21 patients. 18 patients showed decremental response to repetitive stimulation at 3Hz 5 pulses and absence of post tetanic facilitation. Motor conduction studies were abnormal in on (prolonged distal latency and reduced conduction velocity), 'F' responses were abnormal in, sensory nerve conduction was abnormal in two, and simple repetitive response were observed in 11 patients. 4 patients died. In IS neuromuscular junctional dysfunction is the predominant factor.