Post-stroke Bruxism Improvement Following Botulinum Toxin Injection Into Salivary Glands: A Case Report

Sialorrhea and bruxism may occur after central nervous system injury and usually require separate management strategies.The effect of intraglandular botulinum toxin injection on bruxism is not well documented.A 37-year-old woman was admitted for rehabilitation after a right capsulolenticular hemorrhagic stroke.Four months later, she presented with left hemiplegia, dysarthria, dysphagia with aspiration, and severe sialorrhea, with a Drooling Severity and Frequency Scale (DSFS) score of 8/9.Awake bruxism characterized by tonic jaw muscle activity at rest was identified and graded 2 on the Standardised Tool for the Assessment of Bruxism (STAB), with tonic masseter activity on surface electromyography.Ultrasound-guided injections of onabotulinumtoxinA were performed in both parotid glands (30 units per side) and sublingual glands (20 units per side).At three weeks, sialorrhea improved with a DSFS reduction from 8/9 to 4/9.Bruxism decreased from STAB grade 2 to grade 1, with a reduction in masseter electromyographic activity.In this patient, intraglandular botulinum toxin injection for post-stroke sialorrhea was associated with improvement of bruxism.Further studies are required to clarify the relationship between salivary secretion and masticatory motor activity.