PANDAS

PANDAS
Streptococcus pyogenes (stained red), a common group A streptococcal bacterium. PANDAS is hypothesized to be an autoimmune condition in which the body's own antibodies to streptococci attack the basal ganglion cells of the brain, by a concept known as molecular mimicry.
Classification and external resources
Specialty	Neurology
ICD-9-CM	279.49
Patient UK
MeSH	C537163
Orphanet	66624
[]

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) describes a hypothesis that there exists a subset of children with rapid onset of obsessive-compulsive disorder (OCD) or tic disorders and these symptoms are caused by . The proposed link between infection and these disorders is that an initial autoimmune reaction to a GABHS infection produces antibodies that interfere with basal ganglia function, causing symptom exacerbations. It has been proposed that this autoimmune response can result in a broad range of neuropsychiatric symptoms.

The PANDAS hypothesis was based on observations in clinical case studies at the US National Institutes of Health and in subsequent clinical trials where children appeared to have dramatic and sudden OCD exacerbations and tic disorders following infections. There is supportive evidence for the link between streptococcus infection and onset in some cases of OCD and tics, but proof of causality has remained elusive. The PANDAS hypothesis is controversial; whether it is a distinct entity differing from other cases of Tourette syndrome (TS)/OCD is debated.

PANDAS has not been validated as a disease entity; it is not listed as a diagnosis by the International Statistical Classification of Diseases and Related Health Problems (ICD) or the Diagnostic and Statistical Manual of Mental Disorders (DSM).

PANDAS is hypothesized to be an autoimmune disorder that results in a variable combination of tics, obsessions, compulsions, and other symptoms that may be severe enough to qualify for diagnoses such as chronic tic disorder, OCD, and Tourette syndrome (TS or TD). The cause is thought to be akin to that of Sydenham's chorea, which is known to result from childhood leading to the autoimmune disorder acute rheumatic fever of which Sydenham's is one manifestation. Like Sydenham's, PANDAS is thought to involve autoimmunity to the brain's basal ganglia. Unlike Sydenham's, PANDAS is not associated with other manifestations of acute rheumatic fever, such as inflammation of the heart. Pichechero notes that PANDAS has not been validated as a disease classification, for several reasons. Its proposed age of onset and clinical features reflect a particular group of patients chosen for research studies, with no systematic studies of the possible relationship of GAS to other neurologic symptoms. There is controversy over whether its symptom of choreiform movements is distinct from the similar movements of Sydenham's. It is not known whether the pattern of abrupt onset is specific to PANDAS. Finally, there is controversy over whether there is a temporal relationship between GAS infections and PANDAS symptoms.

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