MOTOR NERVE CONDUCTION VELOCITY DURING DIPHENYLHYDANTOIN INTOXICATION

Twenty-four patients with serum diphenylhydantoin (DPH) levels above 20 mg per 1 underwent an examination of the motor conduction velocity (mev) in the right deep peroneal nerve. Subsequently, when the serum DPH level was normalized, each patient was re-examined. For the material as a whole the difference between the paired measurements was significant (p<0.01). However, it could be shown that solely the patients with a serum DPH level above 30 mg per 1 contributed to this difference. No correlation could be found between the serum DPH value under intoxication and the reduction of mev or between the degree of clinical intoxication and the reduction of mcv. Obviously the duration of the intoxication could not account either for the reduction of the examined parameter. Perhaps a combination of the height and the duration of the augmented serum DPH level renders the clue to the question, but for an adequate elucidation of this aspect the material was too small. That temperature differences could account for the differences in mev is unlikely, considering the technique employed. The mcv-reducing effect of DPH must be considered a pharmacological one, and the average value of mcv after correction of the serum DPH leyel did not differ from that of a normal material. Apparently no causal relationship exists between the decrease of mcv and the symptomatology of DPH-intoxication.