A rare case of peripherally induced action-specific movement and sensory disorder of the hand and forearm

Abstract

Hand surgeons are familiar with action-specific focal dystonia like golfer's or musician's dystonia. They may lack expertise in more sophisticated disturbances of the central nervous system which can mimic, by complex neurophysiological processes, the more common peripheral nerve disorders. We present the case of a 34-year-old female journalist. Supraspinatus tendinitis lasting 2 years was treated with arthroscopic subacromial decompression and resection of the acromioclavicular joint 3 years earlier. Pain, cramps and uncontrolled dystonic movements in the ulnar part of her right hand and wrist began shortly after this otherwise uneventful operation. The usual postoperative support of the right arm on an abduction pillow was initially blamed for having triggered compression neuropathy of the ulnar nerve at the elbow, even though nerve conduction studies did not support the clinical diagnosis. Symptoms such as pain on the radial side of the forearm and pronation cramps disputed the diagnosis of ulnar compression neuropathy furthermore. Those seemingly contradictory clinical signs in conjunction with normal electrophysiologic and ultrasound results were conclusively attributed to a typical case of a central action-specific sensory and movement disorder, here of the right hand and forearm. Occupational mirror therapy was successful within a few sessions. The patient, who suffered from nearly continuous pain before, is now symptom-free.