Sydenham chorea (SC), also historically known as "St. Vitus' dance," is a neurological disorder characterized by rapid, jerky, involuntary movements and muscle weakness. It is the most common cause of acquired chorea in children and represents a major manifestation of acute rheumatic fever (ARF), occurring in 20-30% of ARF cases[@tarbox2021]. The condition is named after Thomas Sydenham, the English physician who first described it in 1686[@church2020].
Sydenham chorea is classified as a manifestation of rheumatic fever according to the revised Jones criteria and serves as a major diagnostic criterion. It typically follows streptococcal infection by a latency period of weeks to months, through an autoimmune mechanism involving molecular mimicry between streptococcal antigens and neuronal tissues in the basal ganglia[@swedo2019].
Epidemiology
Sydenham chorea predominantly affects children between the ages of 5 and 15 years, with a mean age of onset around 9 years[@tarbox2021]. There is a female predominance, with females affected approximately twice as often as males. The condition is more common in developing countries and in populations with limited access to healthcare, where rheumatic fever remains prevalent[@church2020].
The incidence of Sydenham chorea has declined dramatically in industrialized nations since the mid-20th century due to antibiotic use and improved living conditions. However, it remains an important cause of childhood chorea worldwide, particularly in resource-limited settings[@swedo2019].
Pathophysiology
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Sydenham Chorea
Overview
Sydenham chorea (SC), also historically known as "St. Vitus' dance," is a neurological disorder characterized by rapid, jerky, involuntary movements and muscle weakness. It is the most common cause of acquired chorea in children and represents a major manifestation of acute rheumatic fever (ARF), occurring in 20-30% of ARF cases[@tarbox2021]. The condition is named after Thomas Sydenham, the English physician who first described it in 1686[@church2020].
Sydenham chorea is classified as a manifestation of rheumatic fever according to the revised Jones criteria and serves as a major diagnostic criterion. It typically follows streptococcal infection by a latency period of weeks to months, through an autoimmune mechanism involving molecular mimicry between streptococcal antigens and neuronal tissues in the basal ganglia[@swedo2019].
Epidemiology
Sydenham chorea predominantly affects children between the ages of 5 and 15 years, with a mean age of onset around 9 years[@tarbox2021]. There is a female predominance, with females affected approximately twice as often as males. The condition is more common in developing countries and in populations with limited access to healthcare, where rheumatic fever remains prevalent[@church2020].
The incidence of Sydenham chorea has declined dramatically in industrialized nations since the mid-20th century due to antibiotic use and improved living conditions. However, it remains an important cause of childhood chorea worldwide, particularly in resource-limited settings[@swedo2019].
Pathophysiology
Autoimmune Basis
Sydenham chorea results from an autoimmune response triggered by group A β-hemolytic streptococcus (GABHS) infection[@tarbox2021]. The mechanism involves:
Molecular mimicry: Antibodies against streptococcal M protein cross-react with neuronal antigens in the basal ganglia (particularly the caudate nucleus and putamen)[@church2020]
Dopaminergic dysfunction: This cross-reactivity leads to dysfunction of dopaminergic [neurons](/entities/neurons) in the striatum
Inflammatory response: Local neuroinflammation contributes to neuronal dysfunction
Neuropathology
Post-mortem studies have shown:
Perivascular lymphocytic infiltrates in the basal ganglia
Loss of neurons in the caudate and putamen
Gliosis without overt necrosis[@swedo2019]
Neuroimaging Findings
MRI may show:
T2 hyperintensities in the caudate nucleus, putamen, or globus pallidus
Diffusion restriction in acute cases
Atrophy of the basal ganglia in chronic cases[@church2020]
Clinical Features
Core Symptoms
The movement disorder in Sydenham chorea has characteristic features[@tarbox2021]:
In severe cases, mutism or severe motor impairment[@church2020]
Disease Course
Onset: Usually insidious, developing over days to weeks
Duration: Typically 2-6 weeks, but can persist for months
Recurrence: Up to 25% of patients experience recurrence, often associated with subsequent streptococcal infections[@swedo2019]
Recovery: Most children make a complete recovery, though some may have residual motor or behavioral issues
Diagnosis
Clinical Criteria
According to the 2015 revised Jones criteria, Sydenham chorea is a major manifestation of acute rheumatic fever. Diagnosis requires[@tarbox2021]:
Evidence of preceding streptococcal infection (positive throat culture, rapid antigen test, or elevated ASO/anti-DNase B titers)
PLUS either:
Two major manifestations, OR
One major and two minor manifestations
Laboratory Findings
Supporting evidence of streptococcal infection[@church2020]:
Elevated anti-streptolysin O (ASO) titer
Elevated anti-DNase B titer
Positive throat culture for GABHS
Other laboratory findings (nonspecific):
Elevated erythrocyte sedimentation rate (ESR)
Elevated C-reactive protein (CRP)
Mild anemia
Leukocytosis
Differential Diagnosis
| Condition | Distinguishing Features | |-----------|------------------------| | Huntington disease | Family history, progressive course, cognitive decline | | Wilson disease | Kayser-Fleischer rings, hepatic dysfunction | | Chorea gravidarum | Occurs in pregnancy | | Drug-induced chorea | Temporal relation to medications | | Autoimmune encephalitis | Psychiatric symptoms, seizures, specific antibodies | | PANDAS | Younger age, abrupt onset, OCD features |
Treatment
General Management
Supportive care[@tarbox2021]:
Safe environment to prevent injury
Nutritional support if feeding difficulties
Physical therapy to maintain function
Psychological support for emotional lability
Antimicrobial Therapy
Penicillin V or erythromycin for streptococcal eradication[@church2020]
Long-term antibiotic prophylaxis may be considered to prevent recurrence
Immunomodulatory Therapy
First-line[@swedo2019]:
Corticosteroids: Prednisone 1-2 mg/kg/day for 2-4 weeks, then taper
May reduce duration of symptoms and prevent recurrence
Second-line[@church2020]:
Intravenous immunoglobulin (IVIG): For severe or steroid-refractory cases
Plasma exchange: May be considered in refractory cases
Symptomatic Treatment
For chorea[@tarbox2021]:
Valproic acid: First-line for movement symptoms
Carbamazepine: Alternative
Benzodiazepines: For anxiety and mild chorea
Tetrabenazine: Reserved for severe, persistent cases
For behavioral symptoms[@church2020]:
SSRIs for OCD symptoms
Behavioral interventions
Prognosis
Long-Term Outcomes
The prognosis for Sydenham chorea is generally favorable[@swedo2019]:
Complete recovery in 70-80% of cases within weeks to months
Recurrence in approximately 25% of cases
Persistent chorea in 10-15% of patients
Most long-term neurological deficits are mild
Cardiac Complications
The major concern in Sydenham chorea is concurrent or subsequent carditis[@tarbox2021]:
60-70% of SC patients have evidence of carditis
Mitral valve disease may develop years later
Regular cardiac follow-up is essential
Relationship to PANDAS
Sydenham chorea is closely related to the PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections) spectrum[@church2020][@swedo2019]. Both conditions:
Follow GABHS infection
Involve autoimmune mechanisms targeting the basal ganglia
May present with choreiform movements and behavioral symptoms
May respond to immunomodulatory therapy
However, Sydenham chorea is defined in the context of acute rheumatic fever, while PANDAS encompasses a broader spectrum of post-streptococcal neuropsychiatric disorders without meeting ARF criteria.
Related Conditions
[Chorea gravidarum](/diseases/chorea-gravidarum) - Chorea occurring during pregnancy