[Painful tonic seizures in multiple sclerosis. Clinical and electromyographic aspects (author's transl)].

This case report deals with a 29 year-old female patient with a prior history of a vestibular syndrome and elapsing optic neuritis that presented paroxystic episodes of painful tonic contractions affecting the right hemibody, especially the upper limb. In the hand the clinical picture was similar to that of the carpal spasm of tetany. When inducing a crisis with ischemia the electromyogram showed diplets, triplets, and multiplets following the appearance of an interference pattern syncronous with contraction of the hand. Occasionally an interference pattern was observed that was associated only to a subjective sensation of paresthesia. During the crisis and in the intercritical periods the following measurements gave normal results: serum calcium, phosphorus, sodium, potassium, magnesium, pH, and pCO2. The administration of calcium had no effect on the frequency and intensity of the crisis. The response to carbemazepine was dramatic, with complete cessation of the crisis and disappearance of the spontaneous activity in the electromyogram. Interruption of treatment one year later was followed by relapse of the painful tonic crisis. The importance of certain electromyographic features and the therapeutic response to carbemazepine in the differential diagnosis of painful tonic crisis and tetany are emphasized. The existence of two clinical-electromyographic patterns in painful tonic crisis is pointed out.