General · EdgepediaSeptember 17, 20267 min read

Sydenham chorea

Sydenham's chorea (also called chorea minor, rheumatic chorea, or St. Vitus dance) is a neurological disorder characterized by involuntary, purposeless, brief, abrupt, irregular, non-stereotyped movements, motor abnormalities, and neurobehavioral symptoms. It is a major manifestation of acute rheumatic fever and results from a dysregulated immune response to Group A β-hemolytic streptococcal (GAS) infection, typically following streptococcal pharyngitis.¹^•²

Key fact	Detail
Cause	Dysregulated immune response to superficial GAS infection; a major manifestation of acute rheumatic fever (ARF)¹
Typical patient	Usual onset at 8–9 years of age, with a female preponderance in most series³
Timing	Chorea typically develops 4–8 weeks after an episode of GAS pharyngitis; SC has not been reported after streptococcal skin infection³
Diagnosis	A modification of the Jones criteria: chorea with acute or subacute onset and lack of evidence of an alternative cause³
Prognosis	Usually clears up in a few months⁴
Relapse prevention	Secondary antibiotic prophylaxis is associated with a 72% decrease in the odds of SC relapse¹
Current guidance	2025 international consensus guidelines from a 27-expert panel, with 88 recommendations¹

History

The first documented epidemic of Sydenham's chorea was in 1418.⁵ In 1686, Thomas Sydenham, the English physician known as "The English Hippocrates" and author of Observationes Medicae, provided an accurate description of the condition he termed chorea minor; he also described rheumatic fever but did not associate the two.⁵^•⁶

The link to rheumatic disease came later. Richard Bright first made the association between chorea and rheumatic fever, dated 1831 in one historical account and 1839 in another.⁵^•⁶ In 1850, See stated that "chorea is the result of a rheumatic diathesis" and that "for every two rheumatic children there is at least one who is choreic."⁷ In 1866, Roger postulated that chorea, arthritis, and heart disease had a common cause.⁸ In the early 1930s, the antistreptolysin O titer became available as an indicator of prior streptococcal pharyngitis, making it possible to establish conclusively that every feature of rheumatic fever, Sydenham's chorea included, follows from group A streptococcal pharyngitis.⁹ Until the 19th century there was speculation that Sydenham's chorea was the same condition as Huntington's disease, which also presents with chorea, but the two are now recognized as clearly different diseases.¹⁰

Clinical features

The chorea itself is a random and continuous flow of contractions. The usual age at onset is 8–9 years, although there are reports of patients developing chorea during the third decade of life, and most series show a female preponderance. Patients typically develop chorea 4–8 weeks after an episode of GAS pharyngitis, and SC has not been reported after streptococcal infection of the skin.³

Neurobehavioral symptoms accompany the movement disorder, and consensus guidance directs clinicians to screen for behavioral, mobility, swallowing, speech, and cognitive impairments as well as ARF features including carditis.¹ Among rheumatic fever patients in whom Sydenham chorea arises, an extremely large share experience carditis and go on to acquire valvular heart disease.¹¹ A previous history of rheumatic fever is infrequent in Sydenham's chorea, especially without heart disease.¹²

Mechanism

An autoimmune mechanism is believed to underlie the condition: antibodies produced against group A β-hemolytic streptococcal antigens cross-react with basal ganglia cells of the central nervous system through molecular mimicry (antibodies accidentally attacking body cells resembling germs).¹¹ Serum antibodies against dopamine D1 and D2 receptors have been identified in enzyme-linked immunosorbent assay titers, although attempts to confirm binding to these receptors in their conformational states in human cell lines have been mixed; this activation is believed to cause clinical symptoms by altering neuronal cell signal transduction, especially involving dopamine.¹³

Epidemiology

Since World War II, rates of both rheumatic fever and SC have fallen in the USA and western Europe, thanks to better medical care, more frequent use of antibiotics, and streptococcal strains of reduced virulence. In Fairfax County, Virginia, the annual age-adjusted incidence of initial rheumatic fever attacks per 100,000 children declined from 3.0 in 1970 to 0.5 in 1980.³ SC primarily affects children living in low-resource regions and in indigenous populations, but still occurs in high-income nations, usually in underserved population groups. The prevalence of rheumatic heart disease, the main sequela of ARF, has increased 1.5-fold since the 1990s.¹

Diagnosis

Today, SC is diagnosed under updated Jones criteria, which call for chorea beginning acutely or subacutely alongside the absence of clinical or laboratory findings pointing to another cause.³ Laboratory markers include anti-streptolysin O and anti-DNase B titers; the relevance of anti-basal ganglia antibodies and dopamine D2 receptor antibody testing is unclear, with specificity not clearly proven.¹⁴ Throat culture for GAS is positive in 25% to 40% of patients with SC.¹⁰ In the consensus guideline's evidence base, evidence of recent streptococcal infection was found in 85% of patients in total but mainly by serological testing, and by positive throat culture in only 37%.¹

The differential diagnosis includes Huntington's disease and other familial choreas, autoimmune encephalitis (in particular anti-NMDAR, anti-GABA_AR and anti-D2R encephalitis), systemic lupus erythematosus and antiphospholipid syndrome, drug intoxication, hyperthyroidism, hypoparathyroidism, Lyme disease, Wilson's disease, and hormonally induced chorea.²^•¹⁵ An alternative etiology such as moyamoya syndrome, benign hereditary chorea, or a functional disorder should be considered in patients with atypical presentation.¹

Treatment

Management can be divided into three areas: penicillin given to prevent recurrence, medications aimed at the symptoms, such as antipsychotic or anticonvulsant drugs, and immune-directed approaches, including steroid treatment, IVIG, and plasma exchange.¹¹

Antibiotics. Antibiotic pharmacotherapy is recommended at diagnosis in all patients with SC, independently of microbiological confirmation of streptococcal throat infection. In the absence of penicillin allergy, a single dose of intramuscular benzathine benzylpenicillin G, or a 10-day course of oral penicillin V or amoxicillin, are the treatments of choice; oral cephalexin or a macrolide may be used with penicillin allergy. Long-term secondary antibiotic prophylaxis is recommended in all children with SC, even in isolated SC without ARF, because of the 72% decrease in the odds of relapse and the prevention of rheumatic heart disease.¹

Symptomatic therapy. In a meta-analysis of first-episode treatment, 78.6% of 687 patients received symptomatic pharmacological treatments, including haloperidol for 36.3% and sodium valproate for 20.5% of 663 patients. Clinician-reported benefit was most frequent for sodium channel blockers (90.0% of 20 patients) and antihistamines (81.2% of 16 patients). Adverse events occurred in 8.8% of 408 patients receiving symptomatic treatments, including severe events attributed to haloperidol in 13 patients, chlorpromazine and other phenothiazines in 9, and sodium valproate in 1.¹⁶ A separate systematic review of 11 articles covering 579 patients found dopamine antagonists, particularly haloperidol, were the primary treatment choice, while valproic acid was favored among antiepileptics.¹⁷

Immunotherapy. In the same meta-analysis, immunotherapy was used in 25.7% of 898 patients: corticosteroids in 23.2%, IVIG in 2.3%, and plasma exchange in 1.3%.¹⁶ Evidence for steroids comes from one placebo-controlled trial along with multiple case series; that trial found that, among 22 patients on high-dose (2 mg/kg) prednisone versus 15 on placebo, chorea improved more quickly (one week instead of two) and full remission arrived sooner (54 days instead of 120).¹³^•¹⁸ The 2025 consensus guidelines recommend corticosteroids for moderate to severe SC, and IVIG or plasma exchange for those with inadequate recovery.¹

Prognosis and related conditions

Sydenham chorea usually clears up in a few months; in rare cases an unusual form may begin later in life.⁴ After SC, recurrence may be triggered not by streptococcal infection but by other triggers such as hormonal changes, including oral contraceptive use or pregnancy, the latter termed chorea gravidarum; some authors postulate this reflects permanent subclinical damage to the basal ganglia after the initial episode.¹⁸

SC also serves as a model for related post-streptococcal neuropsychiatric conditions. Like PANDAS (pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections), it follows streptococcal infection and involves autoimmune-mediated basal ganglia dysfunction, but the overlap in psychiatric symptoms means the two are distinguished on the basis of the neurological examination.² Prevention centers on early treatment of streptococcal sore throats to prevent acute rheumatic fever.⁴

References

Topic: Encyclopedia › Life and health › Human health and medicine › Diseases and injuries › Nervous and sensory conditions › Neurodegenerative diseases, dementias, and prion disease

Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 21, 2026 · Edited: Sep 30, 2026; Oct 21, 2026 · Last review: Oct 21, 2026

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