Sydenham's chorea

What is Sydenham's chorea?

Sydenham's chorea (SC) is a neuropsychiatric movement disorder characterised by rapid and uncoordinated jerking movements, which mainly affect the face, hands and feet. SC is a long-established condition, first described by Thomas Sydenham in 1686. An alternative eponym for SC, ‘Saint Vitus Dance’, makes reference to St. Vitus, martyred in 303 AD, and the manic dancing that historically took place in front of his statue on his feast day.

Pathophysiology 

SC is temporally associated with group A β-hemolytic streptococcus infection, and the diagnosis fulfills Jones criteria for rheumatic fever (RF). Streptococcal pharyngitis caused by group A streptococcus is a common bacterial infection in children and young adults. Most infections are uncomplicated and respond easily to appropriate antibiotics. Infections may be so minor, resolving without intervention, that affected individuals do not seek medical attention. The causal relationship of group A streptococcus infection to SC is supported by epidemiologic observations. These include the temporal relationship to documented infections and co-occurrence of chorea with other manifestations of rheumatic disease, carditis and arthritis, as well as the reduction in SC cases in the post antibiotic era.

Its pathogenesis is not clearly understood, but it is most likely caused by Streptococcus -induced antibodies that cross-react with basal ganglia antigens. The diagnosis of SC relies on the presence of typical clinical features and exclusion of alternative causes.

Prevalence

The prevalence of RF varies across the world however SC is the commonest form of acquired chorea. SC occurs in approximately a third of children suffering from RF and is more common in girls than boys. The prevalence of movement and emotional disorders in first degree family members suggests that a genetic predisposition is important in disease development in addition to environmental and neurochemical triggers. 

Clinical features

The usual age for onset of SC is 8–9 years. However, there have been reports of adult presentations of SC. Typically, patients develop this disease 4–8 weeks after an episode of group A beta-hemolytic streptococcal pharyngitis. It does not occur after streptococcal infection of the skin. The chorea, characterised by a random and continuous flow of contractions, spreads rapidly and usually becomes generalized. Approximately 20% of patients remain affected with hemichorea. SC patients display motor impersistence, particularly noticeable during tongue protrusion and ocular fixation. The muscle tone is usually decreased; in severe and rare cases the decrease of muscle tone can be so pronounced that the patient may become bedridden (chorea paralytica).

Common psychiatric manifestations include obsessive-compulsive disorder, affective disorders, anxiety disorders (e.g. separation anxiety) and cognitive changes such as decreased verbal fluency and dysexecutive syndrome. In addition there have been a number of case reports describing psychotic features presenting in SC.

In up to 50 % of patients, SC has a persistent course and can recur during pregnancy or in women with oestrogen exposure.

Treatment

Based on the clinical presentation of SC, the treatment has four main tenets:

1) Elimination and secondary prophylaxis of streptococcal infection with penicillin.

2) Symptomatic treatment of the involuntary movements and incoordination with anticonvulsants (e.g. Sodium valproate or carbamazepine) or neuroleptics (e.g. Risperidone, Haloperidol, or pimozide) however neuroleptics must be used with caution in SC patients because of the increased risk of extrapyramidal side effects. Although there are anecdotal reports of success in the literature relating to steroids, plasma exchange and IVIG, there is insufficient evidence to support any of these as routine treatment.

3) Symptomatic treatment of psychiatric complications.

4) Supportive measures: Supportive work with the families and liaising with education to ensure that the child’s condition is well understood and supported in school.