[Evaluation of a Neuropsychiatric Disorder: From PANDAS to PANS and CANS]

PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections) syndrome is a disorder seen before adolescence that possesses an abrupt onset of obsessive-compulsive disorder symptoms and/or tics. Swedo and colleagues defined this disorder in 1998 as a syndrome related to Group A streptoccoccus (GAS) infection with neurological issues, such as motor hyperactivation and choreiform movements. The progress of the disorder may be described as wax-and-waning, apart from abrupt onset, and this relapse and remission course is associated with exacerbating infections, according to the creators of PANDAS syndrome. Ruling out of Rheumatoid Fever and Sydenham's Chorea was a necessity for making a proper diagnosis. Since the recognition of this syndrome, clinicians encountered many children who could not fulfill all 5 criteria, which must be met for PANDAS diagnosis. In addition, due to literature showing failure and lack of strong evidence of a major role of GAS, the newly-defined categories PANS (Pediatric Acute-onset Neuropsychiatric Syndrome) and CANS (Childhood Acute Neuropsychiatric Syndrome) were created to encompass those of "almost met" non-PANDAS cases. PANS and CANS include concurrent significant psychiatric symptoms with abrupt onset of OCD symptoms and/or tics but do not require identification of any infection agent, immune dysfunction, or enviromental precipitants. In this paper, we aimed to discuss PANS/ CANS, alterations of PANDAS, and diagnoses in which "almost met" PANDAS patients should be classified on the basis of a case who developed an abrupt onset of anxiety, obsessions, and vocal tics.