[From writer's cramp to butcher's spasms: a case of interprofessional dystonia].

INTRODUCTION: Occupational or professional dystonia is a focal motor dystonic disorder which affect motor programs necessaries for the exercise of the patient's profession. Clinical case. A patient with writer's cramp in the childhood presented at the age of 22 years a new dystonia, which we name 'butcher's spasm', giving rise to a laboral incapacity. Neurological exam was normal except for right arm distal (writer's cramp) and proximal dystonias (butcher's cramp), with intentional tremor in the upper extremities. We classified, after complementary exams, the disease as idiopathic.

CONCLUSIONS: Idiopathic focal dystonias can progress to segmentary or multifocal dystonias, and, in exceptional cases as ours, can interfere with two different professional activities.