STREPTOCOCCAL INFECTION, TOURETTE SYNDROME, AND OCD: IS THERE A CONNECTION? PANDAS: HORSE OR ZEBRA?

Abstract

Schrag et al.1 found “insufficient supportive evidence for a causal relationship between PANDAS and group A SI” (streptococcal infections), which led Gilbert and Kurlan2 to equate pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) to a “rare, unmarked horse” that escapes both detection and description. Neither conclusion is justified by the study design or its results, as the 5 clinical criteria that define PANDAS3 were not used to select the subjects for the investigation. Of the criteria, the sole one met was the presence of OCD or tic disorder; by contrast, unmet criteria were prepubertal onset, episodic course, association with group A streptococcal (GAS) infection, and associated neurologic abnormalities. This sample cannot provide useful information about the PANDAS cohort. Inappropriate ages and clinical presentations were included, and the 2- and 5-year intervals used were too long to allow an etiologic association. The diagnostic codes used to identify SI (see table e-1) included healthy children and individuals with diagnoses specifically known not to be GAS infections. Furthermore, GAS infections were not confirmed for any of the subjects because “too few patient records had supporting diagnostic evidence from throat swabs (n = 67) and ASO titers (n = 6).”1 This fatal flaw should have precluded further analysis, since GAS can be distinguished from other etiologies only by throat culture. In addition, interpretations and significance were based on faulty assumptions. The authors wrote, “finding increased numbers of SIs not treated with antibiotics” among the subjects with obsessive-compulsive disorder (OCD) or tics was “in the opposite direction of predicted.” An increase in untreated GAS infections is the expected result, as cross-reactive antibodies are produced only when the bacteria persist without treatment for 3–5 days or longer.4 In PANDAS, as in the model disorder Sydenham chorea (SC), prompt recognition …