Sydenham's chorea vs Saint Vitus dance

Sydenham's chorea and Saint Vitus dance both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sydenham's chorea	Yes	No	No	No
Saint Vitus dance	Yes	No	No	No

As nouns, Sydenham's chorea and Saint Vitus dance are synonyms defined as:

Sydenham's chorea and Saint Vitus dance: chorea occurring chiefly in children and associated with rheumatic fever

Other synonyms of Sydenham's chorea include St. Vitus dance.

Sydenham's chorea (noun)	Saint Vitus dance (noun)
chorea occurring chiefly in children and associated with rheumatic fever	chorea occurring chiefly in children and associated with rheumatic fever