Sydenham's chorea

Sydenham's chorea or Chorea minor (also known as "Saint Vitus' Dance") is a disease characterized by rapid, uncoordinated jerking movements affecting primarily the face, feet and hands. Sydenham's chorea (SC) results from childhood infection with Group A beta-hemolytic Streptococci and is reported to occur in 20-30% of patients with acute rheumatic fever (ARF). The disease is usually latent, occurring up to 6 months after the acute infection, but may occasionally be the presenting symptom of RF. SC is more common in females than males and most patients are children, below 18 years of age. Adult onset of SC is comparatively rare and most of the adult cases are associated with exacerbation of chorea following childhood SC.

It is named for British physician Thomas Sydenham, (1624–1689). The alternate eponym, Saint Vitus' dance, is in reference to Saint Vitus, a Christian saint who was persecuted by Roman emperors and died as a martyr in AD 303. Saint Vitus is considered to be the patron saint of dancers, with the eponym given as homage to the manic dancing that historically took place in front of his statue during the feast of Saint Vitus in Germanic and Latvian cultures.

Characteristics
SC is characterised by the acute onset (sometimes a few hours) of motor symptoms, classically chorea, usually affecting all limbs. Other motor symptoms include facial grimacing, hypotonia, loss of fine motor control and a gait disturbance. Fifty percent of patients with acute SC spontaneously recover after 2 to 6 months whilst mild or moderate chorea or other motor symptoms can persist for up to and over 2 years in some cases (for example a patient in the UK who has suffered the illness since 1999). Sydenham's is also associated with psychiatric symptoms with obsessive compulsive disorder being the most frequent manifestation. The PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infections) syndrome is similar, but is not characterized by Sydenham's motor dysfunction, but presenting with tics and/or with psychological components (OCD) and much sooner, days to week after GABHS infection rather than 6–9 months. It is related to other illnesses such as Lupus and Tourette's.

Movements cease during sleep, and the disease usually resolves after several months. It is associated with post-streptococcal rheumatic fever, pregnancy, hyperthyroidism, and systemic lupus erythematosus.

Neurologic symptoms of SC include behavior change, dysarthria, gait change, loss of fine and gross motor control with resultant deterioration of handwriting, headache, slowed cognition, facial grimacing, fidgetiness and hypotonia. Nonneurologic manifestations of ARF are carditis, arthritis, erythema marginatum, and subcutaneous nodules.

Causes
A major manifestation of ARF, Sydenham's chorea is a result of an autoimmune response that occurs following infection by group A β-hemolytic streptococci that destroys cells in the basal ganglia. The incidence of ARF and rheumatic heart disease (RHD) is not declining. Recent figures quote the incidence of ARF as 0.6 - 0.7/1 000 population in the USA and Japan compared with 15 - 21/1 000 population in Asia and Africa. The prevalence of ARF and SC has declined progressively in developed countries over the last decades. There are many causes of childhood chorea, including cerebrovascular accidents, collagen vascular diseases, drug intoxication, hyperthyroidism, Wilson's disease, Huntington's disease, and infectious agents.

Treatment or Management
Treatment of SC is based on the following three principles:
 * 1) The first tenet of treatment is to eliminate the streptococcus at a primary, secondary and tertiary level. Strategies involve the adequate treatment of throat and skin infections, with a 10-day course of penicillin when SC is newly diagnosed, followed by long-term penicillin prophylaxis. Behavioural and emotional changes may precede the movement disorders, in a previously well child.
 * 2) Treatment of movement disorders. Therapeutic efforts are limited to palliation of the movement disorders. Haloperidol is frequently used because of its dopaminergic effect as described above. It has serious potential side-effects, e.g. tardive dyskinesia. In a study conducted at the RFC, 25 out of 39 patients on haloperidol reported side-effects severe enough to cause the physician or parent to discontinue treatment or reduce the dose. Other medications which have been used to control the movements include pimozide, clonidine, valproic acid, carbamazepine and phenobarbitone.
 * 3) Immunomodulatory interventions include steroids, intravenous immunoglobulins, and plasma exchange. Patients may benefit from treatment with steroids; controlled clinical trials are indicated to explore this further.

Society and culture
St. Vitus' dance is noted as the malady suffered by the elderly physician from whom Dr. Watson purchased a medical practice in "The Stock-Broker's Clerk" by Arthur Conan Doyle, included in a number of Holmes' stories published collectively in The Memoirs of Sherlock Holmes.

American artist Andy Warhol was afflicted with rheumatic fever as a young child, and developed the symptoms of St. Vitus Dance.