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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 group A beta-hemolytic streptococcal (GABHS) infections.〔 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). Pediatric acute-onset neuropsychiatric syndrome (PANS) is a 2012 proposal describing another subset of acute-onset OCD cases including "not only disorders potentially associated with a preceding infection, but also acute-onset neuropsychiatric disorders without an apparent environmental precipitant or immune dysfunction".〔 ==Classification== 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 Group A streptococcal (GAS) infection 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.〔 To establish that a disorder is an autoimmune disorder, Witebsky criteria require # that there be a self-reactive antibody, # that a particular target for the antibody is identified (autoantigen) # that the disorder can be caused in animals and # that transferring antibodies from one animal to another triggers the disorder (passive transfer). In addition, to show that a microorganism causes the disorder, the Koch postulates would require one show that the organism is present in all cases of the disorder, that the organism can be extracted from those with the disorder and be cultured, that transferring the organism into healthy subjects causes the disorder, and the organism can be reisolated from the infected party.〔 Giovanonni notes that the Koch postulates cannot be used in the case of postinfection disorders (such as PANDAS and SC) because the organism may no longer be present when symptoms emerge, multiple organisms may cause the symptoms, and the symptoms may be a rare reaction to a common pathogen.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「PANDAS」の詳細全文を読む スポンサード リンク
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