[Electromyographic diagnosis of tetany]

Whilst the classical picture of tetany is easily to be diagnosed, diagnostic problems may arouse if vegetative, visceral or vascular symptoms predominate. The well-known clinical signs of provocation (Chvostek, Trousseau, Bonsdorff) frequently do not allow any diagnostic ascertainment. With the help of the classical electrodiagnostics after Erb (in the positive case the provocation of the cathodal opening contraction with an intensity of current below 5 mA is possible) or the electromyography we, as a rule, succeed in proving the diagnosis. In the EMG characteristic repetetive potentials in derivation from a small hand muscle are found, either spontaneous or after provocation by means of ischaemia and hyperventilation. The electromyographic examination is regarded as the most sensitive method in the diagnostic spectre at disposal and should be used for proving or excluding a tetany in unclear stenocardias, vasomotor circulatory disturbances, in spastic disturbances in the gastrointestinal tract, in unclear headache as well as in tetanic cataract and after operations of the thyroid gland.