MedPage Today: Chronic Tics in Kids, Evidence Tilts Against Strep as Cause of Worsening

By Judy George

Children with chronic tic disorders, mainly Tourette syndrome, did not have tic exacerbations when exposed to group A Streptococcus, a longitudinal study suggested.

No significant association with tic exacerbations emerged across four definitions of pharyngeal strep exposure over mean follow-up of 16 months, although trends suggested a possible weak link (OR 1.006-1.235, all P>0.3), reported Davide Martino, MD, PhD, of the University of Calgary in Canada, and co-authors.

However, strep was significantly associated with longitudinal changes of hyperactivity-impulsivity symptom severity that ranged from 17% to 21% depending on how exposure was defined, the team wrote in Neurology.

Group A Streptococcus has been studied as a possible environmental agent associated with tic disorders for the past 2 decades, observed Andrea Cavanna, MD, PhD, of the University of Birmingham in England, and Keith Coffman, MD, of Children's Mercy Hospital in Kansas City, Missouri, in an invited editorial.

"Our study of the largest prospective cohort of youth with chronic tic disorders ever documented to date provides evidence against a temporal association between group A Streptococcus exposure and clinically relevant tic exacerbations," Martino and co-authors wrote.

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Learn more about the Tourette Syndrome Center of Excellence at Children's Mercy