title: Abnormal vocal cord movement treated with botulinum toxin in patients with asthma resistant to optimised management.
abstract: OBJECTIVE
  Abnormal vocal cord movement may coexist with asthma and cause additional upper/middle airway obstruction. The condition may be a form of muscular dystonia that could contribute to asthma resistant to optimised treatments. Botulinum toxin causes temporary paralysis of muscle and may be an effective local treatment that improves asthma control.
  
  
  METHODS
  In an observational study, we evaluated the benefits of unilateral vocal cord injection with botulinum toxin in 11 patients (total 24 injections). Subjects had asthma resistant to optimised treatment and abnormal vocal cord movement. Responses after botulinum toxin treatment were assessed using asthma control test (ACT) scores, vocal cord narrowing quantified by computerised tomography (CT) of the larynx and spirometry. Side-effects were recorded.
  
  
  RESULTS
  ACT scores improved overall (9.1 ± 2.4 before and 13.5 ± 4.5 after treatment; difference 4.4 ± 4.2; P < 0.001). There was also an improvement in airway size on CT larynx (time below lower limit of normal at baseline 39.4 ± 37.63% and improved to 17.6 ± 25.6% after injection; P = 0.032). Spirometry was not altered. One patient experienced an asthma exacerbation but overall side-effects were moderate, chiefly dysphonia and dysphagia.
  
  
  CONCLUSIONS
  Although a placebo effect cannot be ruled out, local injection of botulinum toxin may be an effective treatment for intractable asthma associated with abnormal vocal cord movement. Further mechanistic studies and a double-blind randomised controlled trial of botulinum toxin treatment are merited.
authors.affiliation: Ear, Nose and Throat Surgery, Monash Medical Centre and Monash Institute of Medical Research (MIMR), Monash University, Melbourne, Victoria, Australia.
authors.forename: Malcolm
authors.initials: M
authors.lastname: Baxter
authors.forename: Nizam
authors.initials: N
authors.lastname: Uddin
authors.forename: Sanjay
authors.initials: S
authors.lastname: Raghav
authors.forename: Paul
authors.initials: P
authors.lastname: Leong
authors.forename: Kathy
authors.initials: K
authors.lastname: Low
authors.forename: Kais
authors.initials: K
authors.lastname: Hamza
authors.forename: Peter W
authors.initials: PW
authors.lastname: Holmes
authors.forename: Garun
authors.initials: G
authors.lastname: Hamilton
authors.forename: Dominic
authors.initials: D
authors.lastname: Thyagarajan
authors.forename: Ken
authors.initials: K
authors.lastname: Lau
authors.forename: Philip G
authors.initials: PG
authors.lastname: Bardin
mesh_terms: D065087:Acetylcholine Release Inhibitors / Q000008:administration & dosage / Q000009:adverse effects; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology; D001905:Botulinum Toxins / Q000008:administration & dosage / Q000009:adverse effects; D004351:Drug Resistance; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular / Q000379:methods; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D064706:Vocal Cord Dysfunction / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D014827:Vocal Cords / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000503:physiopathology
chemical_list: D065087:Acetylcholine Release Inhibitors; D018927:Anti-Asthmatic Agents; D001905:Botulinum Toxins
keywords: asthma; botulinum toxin; vocal cord dysfunction