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Sydenham’s chorea (SC), also known as St. Vitus dance, is a neurological manifestation of acute rheumatic fever (ARF). It presents as involuntary, rapid, irregular, and purposeless movements, primarily affecting the face, hands, and feet, and is more common in children and adolescent girls.
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Boy with Sydenham's Chorea | NEJM
Molecular and cellular basis of Sydenham's chorea: In Sydenham's chorea, neurons in the basal ganglia are attacked by antibodies against the group A carbohydrate of Streptococcus spp. that react with the surface of the neuron. This reaction activates signalling through calcium/calmodulin-dependent protein kinase type II (CAMK2), which involves an increase in tyrosine hydroxylase in dopaminergic neurons. Receptors, such as the D1 and D2 dopamine receptors, and lysoganglioside might be autoantibody targets on the neuronal cell. This targeting could lead to altered cell signalling and increased levels of dopamine, in turn leading to abnormal movements and behaviours.
Carapetis, J., Beaton, A., Cunningham, M. et al. Acute rheumatic fever and rheumatic heart disease. Nat Rev Dis Primers 2, 15084 (2016). https://doi.org/10.1038/nrdp.2015.84
| Motor Symptoms | Other Features |
|---|---|
| Involuntary choreiform movements | Emotional lability, irritability |
| Hypotonia (especially in acute phase) | Behavioral changes, OCD-like symptoms |
| Milkmaid’s grip (irregular squeezing) | Speech disturbances (dysarthria) |
| Darting tongue, facial grimacing | Difficulty with fine motor tasks |
| Asymmetrical or generalized movements | Symptoms worsen with stress, disappear in sleep |