RESUMO
The data which addresses the validity of the proposed unique subgroup of children with early and abrupt onset of obsessive-compulsive disorder (OCD) and/or tic disorder subsequent to streptococcal infection was reviewed. The aetiology of OCD and tic disorder is unknown, although it appears that both disorders may arise from a variety of genetic and environmental factors. Post-streptococcal autoimmunity has been postulated as one such mechanism. Although much research remains to be done, an increasing body of evidence provides support for the postulate that OCD may arise from post-streptococcal autoimmunity. The unique clinical characteristic of the PANDAS sub group, the presence of volumetric changes in basal ganglia and the dramatic response to immunomodulatory treatment suggest that symptoms arise from a combination of local, regional and systemic dysfunction and further research is required in order to provide novel strategies of prevention and treatment.