PANDAS — Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infection is a syndrome that combines all neuropsychiatric symptoms in children with a proven autoimmune nature and association with streptococcal infection.
PANS — Pediatric Acute-onset Neuropsychiatric Syndrome is a syndrome also characterized by neuropsychiatric disorders in children, but for which the etiology (viral, bacterial, or tumor-related) is later specified.
The main etiologic factor of PANDAS syndrome is group A beta-hemolytic streptococcus, which causes angina and scarlet fever. It can persist in the body even outside the acute infection, creating conditions for frequent relapses, which in turn increases the risk of autoimmune damage. The immune system attacks its own tissues, because the streptococcus is characterized by so-called "antigenic mimicry" — the similarity of some bacterial proteins to the body's own proteins.
PANS syndrome is generally similar to PANDAS but can be caused by other factors (herpesviruses, toxoplasmosis, M. pneumoniae, borrelia, influenza, tumors, etc.).
PANS is a pediatric neuropsychiatric syndrome with an acute onset. It is characterized by the onset of obsessive-compulsive disorder (OCD), tics, eating disorders, and other changes. PANDAS is considered a subtype of PANS, but the main difference is that it develops against a streptococcal infection and is most commonly diagnosed in children aged 6-8 years. PANS/PANDAS syndrome affects patients between the ages of 3 and 12 years and is most commonly diagnosed in children aged 6-8 years, with 2.6 times as many boys than girls affected.