Group A Β-Hemolytic Streptococcal Infection in Children and the Resultant Neuro-Psychiatric Disorder; A Cross Sectional Study; Tehran, Iran

introduction: group a beta-hemolytic streptococcus (gabhs) can induce pandas(pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection).gabhs is the most important and common bacterial cause of acute pharyngitis in iranianchildren. we studied the role of gabhs (anti-streptococcal antibodies) in suspected cases ofpandas in a cross sectional studies. methods: across sectional study was done in 2 pediatric psychiatric /and neurologic clinicsin tehran (rasul akram and aliasghar hospital) during 2008-2010. we studied serum antistreptococcalantibodies (anti streptolysin o, anti deoxyribonuclease b, and anti-streptokinase(abcam-elisa, usa) in 76 cases with psychiatric manifestation (ocd, adhd) in comparewith 39 healthy controls. these antibodies were studied in 53 cases with movement disorders(tic/ tourette syndrome ) in compare with 76 healthy controls. sensitivity, specificity andpositive predictive value of tests were calculated. results: in movement disorders asot, anti-dnase and anti streptokinase was significantlyhigher than controls (p<0.0001, p=0.000, p<0.00001)asot (cut off level> 200iu/ml) had 75% sensitivity; 84% specificity and 80% ppv; antistreptokinase(cut off level> 332 iu/ml) had 34% sensitivity; 85% specificity, and 72% ppv;anti-dnase (cut off level> 140iu/ml) had 70% sensitivity; 99% specificity and ppv 90% fordifferentiating the group. asot, anti-dnase and anti streptokinase titer was significantly higherthan controls (p<0.0001, p=0.000, p<0.0001). asot had 90% sensitivity; 82% specificity,ppv 92%; anti streptokinase: 82% sensitivity; 82% specificity, ppv 95%; anti dnase: 92%sensitivity; 82% specificity, ppv 92% for differentiation the cases from normal controls. discussion: these findings support that a post infectious immune mechanism to gabhsmay play a role in the pathogenesis of pandas in our children. a combination of throatculture, rapid antigen detection test, and serologic testing for gabhs is required to achievemaximum sensitivity and specificity for diagnosis. we prefer to use antibiotic prophylaxis inpandas cases for preventing recurrent streptococcal infections. ongoing research is neededfor identifying optimum diagnostic, prevention and therapeutic approach especially, aggressivetreatment (intravenous immunoglobulin, plasmaphresis).