Children’s strep infections linked to tics – study

By Andrew Stern

CHICAGO (Reuters) – Strep throat infections triple a
child’s risk of developing compulsive behaviors or tics, an
indication that the same antibodies that attack the infection
may also damage brain cells, a study said on Tuesday.

As many as one in four children develop some kind of tic
disorder that can range from a compulsive ordering of objects
to obsessive hand-washing to the uncontrolled lashing out of
Tourette’s syndrome sufferers.

In many cases, the tic disappears after a period of time,
but Tourette’s and obsessive-compulsive disorder may be
lifelong afflictions that can be quelled only with powerful
drugs.

“Genetics more than likely play a major role in these
conditions, but strep throat might be one of the triggers,”
said Dr. Robert Davis of the Center for Health Studies in
Seattle, one of the authors of the study.

The study identified children aged 4 to 13 with tics who
were patients of Davis’ Seattle-based Group Health Cooperative
between 1992 and 1999, and they were matched with children
without tics.

Based on their medical histories, children with tics were
twice as likely as tic-free children to have had a
streptococcal infection – primarily strep throat – within the
previous three months. For those who had multiple infections,
the risk of developing a tic tripled.

Davis said many scientists believe the body’s response to
infection, and to the antibiotics prescribed to fight it, is to
produce antibodies that attack not only the infection but may
also damage brain cells that control movement and behavior.

“Strep infections share certain proteins that stimulate a
set of antibodies that cross-react with the brain,” he said.

The result is an autoimmune response, where the body’s own
immune system attacks healthy cells as in multiple sclerosis or
lupus. So far, science has failed to find cures for autoimmune
diseases.

Strep infections are common, but Davis said it was too
early to know whether choosing one treatment option or none at
all would help stave off tics.

“This is scientific research at this point,” Davis said.
“One thing we didn’t study was whether treatment (with
penicillin) modifies these conditions.”

The study was published in Pediatrics, the monthly journal
of the American Academy of Pediatrics.