title: Spinal myoclonus in the periscapular muscles after mastectomy assessed by FDG-PET.
abstract: We describe a 64-year-old woman who developed spinal myoclonus around the left scapula after long thoracic nerve injury by mastectomy. Involuntary muscle twitching was semi-rhythmic, and ultrasonography identified contraction of the serratus anterior, teres major, and rhomboid muscles. FDG-PET imaging revealed markedly increased glucose uptake only in the serratus anterior. Lidocaine injection into this muscle resulted in complete cessation of the involuntary movement, and then she was successfully treated with botulinum toxin type A. These findings raise the possibility that the myoclonus was primarily caused by ectopic firing of the injured long thoracic nerve, then spreading to adjacent muscles possibly via a central mechanism mediated by group Ia afferents. The new imaging tools, such as FDG-PET and ultrasonography, were useful to determine the therapeutic target muscle.
authors.affiliation: Department of Neurology, Graduate School of Medicine, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8670, Japan. sonoko.m@mb.infoweb.ne.jp
authors.forename: S
authors.initials: S
authors.lastname: Misawa
authors.forename: S
authors.initials: S
authors.lastname: Hayakawa
authors.forename: K
authors.initials: K
authors.lastname: Himuro
authors.forename: S
authors.initials: S
authors.lastname: Sawai
authors.forename: Y
authors.initials: Y
authors.lastname: Akaogi
authors.forename: S
authors.initials: S
authors.lastname: Ito
authors.forename: S
authors.initials: S
authors.lastname: Kuwabara
mesh_terms: D019274:Botulinum Toxins, Type A / Q000627:therapeutic use; D020820:Dyskinesias / Q000209:etiology; D004576:Electromyography; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008408:Mastectomy / Q000009:adverse effects*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000503:physiopathology; D009207:Myoclonus / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000209:etiology*; D009465:Neuromuscular Agents / Q000627:therapeutic use; D049268:Positron-Emission Tomography; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000188:drug therapy; D019275:Radiopharmaceuticals; D012540:Scapula / Q000502:physiology; D014463:Ultrasonography
chemical_list: D009465:Neuromuscular Agents; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D019274:Botulinum Toxins, Type A