This patient is presenting with Sydenham chorea, which is erratic, purposeless movements associated with rheumatic fever. Symptoms are often asymmetric choreiform movements, emotional lability, and hypotonia. It is one of the five major criteria for rheumatic fever, an autoimmune syndrome seen 1-6 months after streptococcal pharyngitis. The other criteria for rheumatic fever include polyarthritis, carditis, erythema marginatum, and subcutaneous nodules. Penicillin is the treatment of choice and patients usually recover within 12-15 weeks.