Pediatric Movement Disorders - Tics

Mechanism

The cause of tics and these associated disorders is not known. The association with other basal ganglia disorders suggests that tics may represent release phenomena with insufficient inhibition by the basal ganglia. However, direct evidence for this suggestion is not available. Treatment of tics is usually most successful with medications such as neuroleptics that block the type 2 dopamine (D2) receptors. The reason for this is not yet known but is presumed to be due to facilitation of the inhibitory indirect basal ganglia pathway. Akathisia may be caused by the same medicines that treat tics. So, the relation between these two disorders is unknown.

There has been speculation that infection with streptococcus may lead to tics and even Tourette's syndrome. This hypothesis has been based on the association of streptococcal infection with another basal ganglia disorder, Sydenham's chorea. The resulting syndrome has been labeled "pediatric autoimmune neuropsychiatric disorder associated with streptococcus (PANDAS)." This syndrome is presumed to include obsessive-compulsive traits and other behavioral changes. However, it remains difficult to prove a direct association between streptococcus and tic disorders. Thus far, studies have not been able to show any improvement in the tics when children are treated with antibiotics for streptococcus. The frequency of both streptococcal infections and tics in children makes it difficult to prove a clear statistical relation.