PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections) and PANS (Pediatric Acute-onset Neuropsychiatric Syndrome)
PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections) and PANS (Pediatric Acute-onset Neuropsychiatric Syndrome) are immune-mediated neuropsychiatric disorders characterized by the abrupt onset of obsessive-compulsive behaviors, tics, and mood or anxiety disturbances. In PANDAS, the condition is triggered by Group A Streptococcus infections, whereas PANS can be precipitated by a broader range of infectious, inflammatory, or autoimmune events. Although historically described in children, emerging evidence suggests that adult-onset PANDAS/PANS may occur, likely due to lingering or reactivated autoimmune responses. Estimated prevalence in children is low, with PANDAS affecting roughly 0.2–1% of school-aged children, though exact rates are difficult to determine due to underdiagnosis and overlapping conditions. The underlying pathophysiology involves autoantibodies that cross-react with basal ganglia proteins (e.g., dopamine D1/D2 receptors, lysoganglioside GM1, and tubulin), triggering microglial activation, dopaminergic dysregulation, and disruption of cortico-striatal-thalamo-cortical circuits, which collectively produce the hallmark neuropsychiatric symptoms.