Botulinum toxin treatment for oropharyngeal dysphagia associated with diabetic neuropathy

No specific treatment for oropharyngeal dysphagia related to diabetic neuropathy has been described to date. Chemical myotomy of the cricopharyngeus (CP) muscle by botulinum neurotoxin type A (BoNT/A) has been effective in reducing or abolishing dysphagia associated with upper esophageal sphincter (UES) hyperactivity of different etiologies. In the present study, we evaluated the efficacy of BoNT/A injections into the CP muscle in diabetic patients with severe oropharyngeal dysphagia associated with diabetic autonomic and/or somatic peripheral neuropathy.

Twelve type 2 diabetic patients with severe dysphagia for both solid and liquid foods associated with autonomic and/or peripheral somatic neuropathy were investigated. Swallowing function was evaluated by clinical examination, videofluoroscopy, and simultaneous needle electromyography (EMG) of the CP and pharyngeal inferior constrictor (IC) muscles. Clinical evaluation using a four-level dysphagia severity score was performed every other day for the 1st week and thereafter every other week until week 24. Videofluoroscopy and EMG follow-up were carried out at week 1, 4, 12, 16, 18, and 24 after BoNT/A injection. BoNT/A was injected percutaneously into the CP muscle under EMG control.

BoNT/A induced the complete recovery of dysphagia in 10 patients and had a significant (P = 0.0001, ANOVA) improvement in 2 patients within 4 +/- 1.1 days (range 3-7). Clinical improvement was confirmed by videofluoroscopy and EMG.

Our findings suggest a potential benefit from BoNT/A treatment in dysphagia associated with diabetic neuropathy. Randomized controlled trials are needed to confirm this observation.