title: Muscle paralysis produced by botulinum toxin type A injection in treated torticollis patients compared with toxin naive individuals.
abstract: We sought to determine whether the response to varying doses of botulinum toxin type A (BTX-A) injected in BTX-A-treated torticollis patients differed from the same injections given in toxin-naive individuals. We have developed a technique to objectively measure muscle weakness resulting from BTX injections in humans and have validated the technique in those not previously treated with BTX. We now examine BTX-A-treated torticollis patients to see if their response to BTX-A injection is similar to that of toxin-naive individuals. We injected 11 torticollis patients who had been receiving BTX-A injections with a standard 5-mouse unit (mu) dose into one extensor digitorum brevis (EDB) muscle and a varying dose into the other EDB, measuring muscle paralysis 2 weeks after the injection. Nine of the 11 patients were clinical and electrophysiologic responders. Two patients were non-responders. In the 9 responding patients the dose response curve to increasing doses of BTX-A was very similar to that seen in toxin-naive individuals. The mean muscle paralysis from the standard 5 mu dose was also similar to that previously reported in toxin-naive individuals. Torticollis patients who continue to respond clinically to BTX-A injections demonstrate essentially the same degree of muscle paralysis from the EDB injections as do subjects who have never been exposed to BTX-A.
authors.affiliation: Department of Neurology, Loma Linda University School of Medicine, California, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Sloop
authors.forename: D
authors.initials: D
authors.lastname: Cole
authors.forename: M C
authors.initials: MC
authors.lastname: Patel
mesh_terms: D000328:Adult; D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005528:Foot; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009465:Neuromuscular Agents / Q000008:administration & dosage / Q000009:adverse effects*; D010243:Paralysis / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology*; D012720:Severity of Illness Index; D014103:Torticollis / Q000188:drug therapy*
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A