Sydenham's chorea

Sydenham's chorea, also known as chorea minor and historically referred to as St Vitus' dance, is a disorder characterized by rapid, uncoordinated jerking movements primarily affecting the face, hands and feet. Sydenham's chorea results from childhood infection with Group A beta-haemolytic Streptococcus and is reported to occur in 20–30% of people with acute rheumatic fever. The disease is usually latent, occurring up to 6 months after the acute infection, but may occasionally be the presenting symptom of rheumatic fever. Sydenham's chorea is more common in females than males and most below 16 years of age. Adult onset of Sydenham's chorea is comparatively rare and the majority of the adult cases are associated with exacerbation of chorea following childhood Sydenham's chorea. Sydenham's chorea, also known as chorea minor and historically referred to as St Vitus' dance, is a disorder characterized by rapid, uncoordinated jerking movements primarily affecting the face, hands and feet. Sydenham's chorea results from childhood infection with Group A beta-haemolytic Streptococcus and is reported to occur in 20–30% of people with acute rheumatic fever. The disease is usually latent, occurring up to 6 months after the acute infection, but may occasionally be the presenting symptom of rheumatic fever. Sydenham's chorea is more common in females than males and most below 16 years of age. Adult onset of Sydenham's chorea is comparatively rare and the majority of the adult cases are associated with exacerbation of chorea following childhood Sydenham's chorea. Sydenham's chorea is characterized by the abrupt onset (sometimes within a few hours) of neurologic symptoms, classically chorea, usually affecting all four limbs. Other neurologic symptoms include behavior change, dysarthria, gait disturbance, loss of fine and gross motor control with resultant deterioration of handwriting, headache, slowed cognition, facial grimacing, fidgetiness and hypotonia. Also, there may be tongue fasciculations ('bag of worms') and a 'milk sign', which is a relapsing grip demonstrated by alternate increases and decreases in tension, as if hand milking. Non-neurologic manifestations of acute rheumatic fever are carditis, arthritis, erythema marginatum, and subcutaneous nodules. The PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) syndrome is similar, but is not characterized by Sydenham's motor dysfunction. PANDAS presents with tics and/or a psychological component (e.g., OCD) and occurs much earlier, days to weeks after GABHS infection rather than 6–9 months later. It may be confused with other conditions such as lupus and Tourette syndrome. Movements cease during sleep, and the disease usually resolves after several months. Unlike in Huntington's disease, which is generally of adult onset and associated with an unremitting autosomal dominant movement disorder and dementia, neuroimaging in Sydenham's chorea is normal and other family members are unaffected. Other disorders that may be accompanied by chorea include abetalipoproteinemia, ataxia-telangiectasia, biotin-thiamine-responsive basal ganglia disease, Fahr disease, familial dyskinesia-facial myokymia (Bird-Raskind syndrome) due to an ADCY5 gene mutation, glutaric aciduria, Lesch-Nyhan syndrome, mitochondrial disorders, Wilson disease, hyperthyroidism, lupus erythematosus, pregnancy (chorea gravidarum), and side effects of certain anticonvulsants or psychotropic agents. A major manifestation of acute rheumatic fever, Sydenham's chorea is a result of an autoimmune response that occurs following infection by group A β-hemolytic streptococci that destroys cells in the corpus striatum of the basal ganglia. Molecular mimicry to streptococcal antigens leading to an autoantibody production against the basal ganglia has long been thought to be the main mechanism by which chorea occurs in this condition. In 2012, antibodies in serum to the cell surface antigen; dopamine 2 receptor were shown in up to a third of patients in a cohort of Sydenham's chorea. Dopamine receptor autoantibodies correlate with clinical symptoms. Whether these antibodies represent an epi-phenomenon or are pathogenic, remains to be proven. There are many causes of childhood chorea, including cerebrovascular accidents, collagen vascular diseases, drug intoxication, hyperthyroidism, Wilson's disease, Huntington's disease, abetalipoproteinemia, Fahr disease, biotin-thiamine-responsive basal ganglia disease due to mutations in the SLC19A3 gene, Lesch-Nyhan syndrome, and infectious agents.