Studies Of The Relationship Of GAS to OCD/PANDAS
Findings: (N=12) Patient had abrupt appearance of severe OCD behaviors, accompanied by mild symptoms and signs of acute GABHS tonsillopharyngitis. Recurrence occurred in 6 patients with GABHS confirmed by culture. Symptoms resolved with antibiotics.
Critique: sample size is small with no explicit control
REFERENCE: [Snyder 2002]
Findings: (N=553, K-6) Motor tics and problem behaviors are frequent occurrences among school age children and occurred more frequently in winter months. For the majority of children, the tics were mild and observed on only one occurrence.
Critique: association with GABHS was not established
REFERENCE: [Mell 2002]
Findings: (N=142, boys=102, girls=42, C=609) Epidemiologic study that patients with OCD, TS or tic disorder were more likely to have prior strep infection in the 3 months before onset. Risk was higher for children with multiple strep infections in prior 12 months. Subjects were selected based on access to laboratory confirmation of GABHS infection.
Critique: study was on single clinic and needs repeat. Ratio of girls low.
REFERENCE: [Leslie 2008]
Findings: (N=108, C=331) No significant association was found between a GABHS infection in preceding year and subsequent diagnosis for TS, OCD or tic disorder. However, children with TS, OCD or tic disorder were 3 times more likely to have a subsequent GABHS infection than controls.
Critique: Unlike Mell, study did not have laboratory confirmation of GABHS. Accuracy of time of onset of TS, OCD, tic disorder similarly unclear from reports.
REFERENCE: [Murphy 2007]
Findings: (N=639) Behavior/tic abnormalities strongly correlated with positive culture for GABHS in the preceding 3 months (p<.0001). Children with repeated GABHS infections showed increased observation of behavior and distal choreiform (p=.005)
Critique: Potential rating bias due to researchers not being blinded to GABHS results
REFERENCE: [Garvey 1999]
Findings: (N=37, double-blind, cross-over) Infections were not prevented in the children on prophylaxis. There was no change seen in OCD or symptom severity in the cross-over.
Critique: Patients failed to comply with daily antibiotic dosing and therefore prophylaxis was not achieved. No conclusions can be drawn from this study.
REFERENCE: [Snyder 2005]
Findings: (N=23, double-blind) Subjects meeting the PANDAS criteria were selected. Prophylaxis was achieved with both azithromycin and penicillin. Significant decreases in neuropsychiatric exacerbations were found in both the azithromycin and penicillin group (p<.01).
Critique: While results are compelling, the use of an active placebo limits conclusions. Study needs to be repeated with an inactive placebo.