[1] Sydenham's chorea is an autoimmune disease that results from childhood infection with Group A beta-haemolytic Streptococcus.

The disease occurs typically a few weeks, but up to 6 months, after the acute infection, which may have been a simple sore throat (pharyngitis).

Underlying the abnormal movements is often low tone (hypotonia) which may not become obvious until treatment is started to suppress the chorea.

[7] Non-neurologic manifestations of acute rheumatic fever may be present, namely carditis (up to 70% of cases, often subclinical, so echocardiography required), arthritis, erythema marginatum, and subcutaneous nodules.

Differentiating these signs from other involuntary movements such as tics and stereotypies can be difficult, and since these things are not uncommon they can potentially co-exist.

The controversial PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) hypothesis has overlapping clinical features, but Sydenham's chorea is one of the exclusion criteria.

Although some of these can similarly present in an acute way, there will typically be other neurological signs (such as ataxia or cognitive impairment), or other disease manifestations, or positive family history, which will help distinguish between them.

[11] One of the important manifestations of acute rheumatic fever, Sydenham's chorea is believed to be caused by an autoimmune response following infection by group A β-hemolytic streptococci.

[12][4] Two cross-reactive streptococcal antigens have been identified, the M protein and N-acetyl-beta-D-glucosamine, whereby infection leads to autoantibodies being produced against host tissues (molecular mimicry) causing a variety of streptococcal related diseases including Sydenham's chorea but also rheumatic heart disease and nephritic syndrome.

Further testing is directed more towards alternative diagnoses and other manifestations of rheumatic fever: Management of Sydenham's chorea is based on the following principles: Treatment with sodium valproate is effective for controlling symptoms, but it does not speed up recovery.

Case reports exist to support carbamazepine and levetiracetam; other drugs tried include pimozide, clonidine, and phenobarbitone.

[25] Penicillin prophylaxis is essential to treat cardiac features of rheumatic fever, even if subclinical (American Heart Association guideline).

[26] If there are not features to warrant a diagnosis of rheumatic fever, it is arguable whether cardiac risk justifies prophylaxis or not; however, it is likely to reduce recurrence.

There are several historical case series reporting successful treatment of Sydenham's chorea by inducing fever.

[32] The prevalence of Acute Rheumatic Fever and Sydenham's Chorea has declined progressively in developed countries over the last decades.