[Neurological signs in diphenylhydantoin intoxication (case reports and review) (author's transl)].

Five patients who were treated with long-term diphenylhydantoin for epilepsy developed neurological signs of poisoning. In 4 cases the symptoms appeared following treatment of status epilepticus with additional phenytoin medication. All patients had an acute symptomatic psychosis and a diffuse slowing of the curves in the EEG. All 5 patients showed cerebellar signs and two of them complained additionally of objective polyneuropathy, a third case complaining of itching only. An axonal polyneuropathy with minimal reduction in motor nerve conduction and a considerable extension of distal latency and diminution of compound action potential was found. In one case the biopsy showed concentric lamellar bodies coming from the axon, with intact myelin sheaths. All alterations were reversible. The pathogenesis of toxicity is discussed. Cumulation of toxic products in the plasma arising from delayed elimination of DPH metabolites is pointed out. However, one case with cerebellar signs had normal DPH levels.