Myotonia congenita is a rare disorder caused by a defect in the skeletal muscle chloride channel function, which may cause sustained membrane depolarisation. We report a case regarding a 52-year-old man affected by this muscular pathology and scheduled for shoulder surgery that was performed under sedation and peripheral nerve block. The international literature does not elucidate clear preference toward a particular anaesthesia technique, but we believe that in this setting, regional anaesthesia and complete monitoring should be preferentially utilized when possible. In any case, the anaesthesia plan should be prudent and avoid exposure to known dangerous anaesthetics.