(422) Therapeutic Utility of Pyridostigmine for Distant Botulinum Dissemination Following Cervicofacial Injection: A Systematic Review

Introduction: Cervicofacial injection of botulinum toxin is used for cosmesis and therapeutic management of hyperkinetic disorders. Rarely, systemic absorption of the toxin can cause neuromuscular weakness, for which treatment options beyond antitoxin are limited. This systematic review aims to investigate the characteristics and outcomes of patients treated with pyridostigmine, an acetylcholinesterase inhibitor, for distant dissemination of botulinum toxin following cervicofacial injection.

Methods: PubMed, Embase, Cochrane, and Scopus databases were searched for studies describing pyridostigmine use in distant botulinum spread. Of 472 articles screened, 15 met inclusion criteria. Eligible studies were limited to case reports/series and retrospective reviews describing pyridostigmine treatment for distant botulinum effects following cervicofacial injection.

Results: Thirty-one patients were included with mean age 47.8 years (17 female, 4 male, 10 unreported). Indications for botulinum injection included adductor spasmodic dysphonia (41.9%), aesthetics (25.5%), and sialorrhea (6.5%). Common symptoms were dysphagia (45.2%), ptosis (25.8%), and generalized weakness (22.6%). After pyridostigmine initiation, 30 patients had improved symptoms after a mean of 6.1 days, with 3 patients noting immediate benefit after administration. Of note, 4 partial responders required adjunct antitoxin. In 2 cases, botulinum injection unmasked myasthenic gravis, with neuromuscular symptoms improving with pyridostigmine despite its limited utility in true myasthenic crisis.

Conclusions: Pyridostigmine may offer an effective treatment for distant botulinum dissemination following cervicofacial injection. Further research is needed to define optimal patient selection and criteria for antitoxin escalation.