Final answer:
Sydenham's chorea is typically associated with rheumatic fever and involves involuntary movements, emotional instability, and muscle weakness, occurring as an autoimmune reaction to a prior group A Streptococcus infection.
Step-by-step explanation:
Sydenham's chorea is a disease that one would suffer in association with rheumatic fever. This condition is characterized by rapid, involuntary, and purposeless movements of the face and limbs, emotional lability, and muscle weakness. It is believed to be an autoimmune reaction that can occur after an infection with group A Streptococcus bacteria, often as a complication of rheumatic fever. This is known to affect the brain and nervous system, causing these characteristic movements.