Treatment of Laryngeal Dystonia with Botulinum Toxin Tratamento da Distonia Laríngea com Toxina Botulínica

Abstract

INTRODUCTION: Focal laryngeal dystonia encompasses a set of pathological processes, characterized by involuntary and intermittent contractions of the internal laryngeal muscles, which can affect predominantly phonatory or respiratory tasks. The injection of botulinum toxin into the affected muscles causes a transient paralysis, allowing a good symptomatic control in these patients.
METHODS: Retrospective analysis of patients with laryngeal dystonia undergoing treatment with botulinum toxin in the Otolaryngology department of our institution between January/2011 and December/2016.
RESULTS: During the 6-year interval, 11 patients with laryngeal dystonia were identified (91% female, mean age 42 years). In this group, 45.5% had adductor type laryngeal dystonia and 9.1% mixed type, while 45.5% presented respiratory laryngeal dystonia.
These patients underwent 43 injections of botulinum toxin (mean of four procedures per patient), in which 39.5% were performed in an outpatient clinic under electromyographic control and 60.5% under general anesthesia. The injections were unilateral in 30.2% and bilateral in 67.4%. The mean dose injected was 11.7 U per session. Partial or total symptomatic improvement occurred in 83.7%, with temporary dysphagia after 20.9% of the procedures. The median duration of botulinum toxin effect was 7 months.
DISCUSSION AND CONCLUSION: Laryngeal dystonia is thought to arise from chronic neurological disorders of central motor processing and considerable delays still occur before appropriate therapeutic intervention, due to difficulties in achieving the correct diagnosis. Among several medical and surgical treatments, botulinum toxin remains nowadays as the first-line treatment, although individual optimization of the therapeutic dose may limit the initial results.