Since the 17th century when Sydenham's chorea (SC) was described, no other neuropsychiatric entity was attributed to streptococcal infections until recently. PANDAS (pediatric autoimmune neuropsychiatric disorder associated with a streptococcal infection) was first described by Swedo et al (1998). Criteria include prepubertal sudden onset of obsessive compulsive disorder (OCD) and/or tics with neuropsychiatic symptoms (hyperactivity, emotional lability, anxiety, or choreiform movements) temporally associated with streptococcal infection. Whereas the association between SC and streptococcal infections is robust, casual and temporal association between tics/OCD and streptococcal infection in PANDAS remains challenging since these are common in school-aged children.
CANS (childhood acute neuropsychiatric symptoms), another entity defined by Singer et al (2011), includes dramatic onset of symptoms. This classification of a group of disorders with multiple causal factors has little practical implication. While active search for specific causes cannot be overemphasized, extensive lists of etiologies adds little to regular clinical practice.
PANDAS-CANS debate demonstrates different psychiatric (PANDAS)/ neurologic (CANS) approaches. Recent studies demonstrated that PANDAS with "choreiform" movements have a similar autoimmune profile to SC (anti-D1/2-Receptor antibodies); thus these cases should be regarded as SC. Non-motor manifestations such as emotional lability and OCD are common in SC and fall within the PANDAS spectrum.
Regardless of ongoing terminology debate there are 2 main messages:
1) Acute onset of neuropsychiatric disorders cannot be regarded as PANDAS without further etiological evaluation excluding treatable causes.
2) Children with chorea after streptococcal infections, including those with "PANDAS with choreiform movements", should be regarded and treated as SC requiring prophylactic penicillin treatment.