Preventive Measures for Childhood-Onset Obsessive-Compulsive Disorder and Tic Disorders (PANDAS Subgroup)

A subgroup of patients with childhood-onset obsessive-compulsive disorder (OCD) and/or tic disorders has been identified who share a common clinical course characterized by dramatic onset and symptom exacerbations following group A beta-hemolytic streptococcal (GABHS) infections. This subgroup is designated by the acronym PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections). There are five clinical characteristics that define the PANDAS subgroup: presence of OCD and/or tic disorder; prepubertal symptom onset; sudden onset or abrupt exacerbations (relapsing-remitting course); association with neurological abnormalities (presence of adventitious movements or motoric hyperactivity during exacerbations); and temporal association between symptom exacerbations and GABHS infections. In this subgroup, periodic exacerbations appear to be triggered by GABHS infections in a manner similar to that of Sydenham's chorea, the neurological variant of rheumatic fever. Rheumatic fever is a disorder with a presumed post-streptococcal autoimmune etiology. The streptococcal pathogenesis of rheumatic fever is supported by studies that have demonstrated the effectiveness of penicillin prophylaxis in preventing recurrences of this illness. A trial of penicillin prophylaxis in the PANDAS subgroup demonstrated that penicillin was not superior to placebo as prophylaxis against GABHS infections in these children, but this outcome was felt to be secondary to non-compliance with treatment, and there was no decrease in the number of neuropsychiatric symptom exacerbations in this group. In a study comparing azithromycin and penicillin, both drugs were completely effective in preventing streptococcal infections - there were no documented titer elevations during the year-long study period for children taking either penicillin or azithromycin. Comparable reductions in the severity of tics and obsessive-compulsive symptoms were also observed. Thus, penicil