Sydenham's chorea
Sydenham's chorea, also known as chorea minor and historically and occasionally referred to as St Vitus' dance, is a disorder characterized by rapid, uncoordinated jerking movements primarily affecting the face, hands and feet. Sydenham's chorea results from childhood infection with Group A beta-haemolytic Streptococcus and is reported to occur in 20–30% of people with acute rheumatic fever. The disease is usually latent, occurring up to 6 months after the acute infection, but may occasionally be the presenting symptom of rheumatic fever. Sydenham's chorea is more common in females than males and most below 16 years of age. Adult onset of Sydenham's chorea is comparatively rare, and the majority of the adult cases are associated with exacerbation of chorea following childhood Sydenham's chorea.
Signs and symptoms
Sydenham's chorea is characterized by the abrupt onset of neurologic symptoms, classically chorea, usually affecting all four limbs. Other neurologic symptoms include behavior change, dysarthria, gait disturbance, loss of fine and gross motor control with resultant deterioration of handwriting, headache, slowed cognition, facial grimacing, fidgetiness and hypotonia. Also, there may be tongue fasciculations and a "milk sign", which is a relapsing grip demonstrated by alternate increases and decreases in tension, as if hand milking.Non-neurologic manifestations of acute rheumatic fever are carditis, arthritis, erythema marginatum, and subcutaneous nodules.
The PANDAS syndrome is similar, but is not characterized by Sydenham's motor dysfunction. PANDAS presents with tics and/or a psychological component and occurs much earlier, days to weeks after GABHS infection rather than 6–9 months later. It may be confused with other conditions such as lupus and Tourette syndrome.
Movements cease during sleep, and the disease usually resolves after several months. Unlike in Huntington's disease, which is generally of adult onset and associated with an unremitting autosomal dominant movement disorder and dementia, neuroimaging in Sydenham's chorea is normal and other family members are unaffected. Other disorders that may be accompanied by chorea include abetalipoproteinemia, ataxia–telangiectasia, biotin-thiamine-responsive basal ganglia disease, Fahr disease, familial dyskinesia–facial myokymia due to an ADCY5 gene mutation, glutaric aciduria, Lesch–Nyhan syndrome, mitochondrial disorders, Wilson disease, hyperthyroidism, lupus erythematosus, pregnancy, and side effects of certain anticonvulsants or psychotropic agents.
Causes
A major manifestation of acute rheumatic fever, 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 corpus striatum of the basal ganglia. Molecular mimicry to streptococcal antigens leading to an autoantibody production against the basal ganglia has long been thought to be the main mechanism by which chorea occurs in this condition. In 2012, antibodies in serum to the cell surface antigen; dopamine 2 receptor were shown in up to a third of patients in a cohort of Sydenham's chorea. Dopamine receptor autoantibodies correlate with clinical symptoms.Diagnosis
The health care provider will perform a physical exam. Detailed questions will be asked about the symptoms.If a streptococcus infection is suspected, tests will be done to confirm the infection. These include:
- Throat swab
- Anti-DNAse B blood test
- Antistreptolysin O blood test
- Blood tests such as erythrocyte sedimentation rate, complete blood count
- Magnetic resonance imaging or computed tomography scan of the brain
Treatment
- 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 course of penicillin when Sydenham's chorea is newly diagnosed, followed by long-term penicillin prophylaxis. Behavioural and emotional changes may precede the movement disorders in a previously well child.
- Treatment of movement disorders. Therapeutic efforts are limited to palliation of the movement disorders. Haloperidol is frequently used because of its anti-dopaminergic effect. 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.
- 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.
- There are several historical case series reporting successful treatment of Sydenham's chorea by inducing fever.
Prognosis
History
Sydenham's chorea became a well defined disease entity only during the second half of the nineteenth century. Such progress was promoted by the availability of large series of clinical data provided by newly founded paediatric hospitals. A 2005 study examined the demographic and clinical features of patients with chorea admitted to the first British paediatric hospital between 1852 and 1936. The seasonal and demographic characteristics of Sydenham's chorea during this time appear strikingly similar to those observed today, Great Ormond Street hospital case notes provide detailed descriptions of the "typical cases" of Sydenham's chorea, and show that British physicians working in the early age of paediatric hospitals recognized the most distinctive clinical features of this condition.Throughout the nineteenth century the term "chorea" referred to an ill-defined spectrum of hyperkinesias, including those recognised today as chorea, tics, dystonia, or myoclonus. William Osler stated, "In the whole range of medical terminology there is no such olla podrida as Chorea, which for a century has served as a sort of nosological pot into which authors have cast indiscriminately affections characterised by irregular, purposeless movements."
Sydenham's chorea, a frequent cause of paediatric acute chorea, is a major manifestation of rheumatic fever. The association of chorea with rheumatism was first reported in 1802, and confirmed in the following decades by several French and English authors. The inclusion of chorea under the rheumatic umbrella helped discriminate Sydenham's chorea from other "choreic" syndromes. The incidence of acute rheumatic fever and rheumatic heart disease is not declining. Recent figures quote the incidence of Acute Rheumatic Fever as 0.6–0.7/1,000 population in the United States and Japan compared with 15–21/1,000 population in Asia and Africa. The prevalence of Acute Rheumatic Fever and Sydenham's Chorea has declined progressively in developed countries over the last decades. Physicians working in early children's hospitals recognised new clinical syndromes through the definition of "typical clinical cases". Complex multi-systemic diseases, such as rheumatic fever, were categorised only after the observation of large, hospital based series. Therefore, paediatric hospitals gradually became an important setting for the application of a modern "statistical averaging" technique to paediatric syndromes. Historical authorities in paediatrics, such as Walter Butler Cheadle and Octavius Sturges, worked at London's Hospital for Sick Children, and their clinical notes help elucidate how the typical case of Sydenham's chorea was defined.
Between 1860 and 1900 the proportion of choreic patients ranged between 5% and 7% of the total number of patients admitted, whereas from 1900 to 1936 it was constantly below 4%. Chorea was the fourth most frequent cause of admission between 1860 and 1900, and in the 1880s temporarily became the second most frequent diagnosis among inpatients. Contemporary articles report a homogeneous distribution of paediatric chorea all over England However, since many choreic children were "cured" at home, the hospital based rates probably underestimate the incidence of chorea in the general paediatric population.
A higher number of cases were admitted during the colder months, consistent with the reference epidemiological report on chorea at the end of the century. In the 1950s and 1960s the highest frequency of chorea was recorded during the winter months in several Northern and Central European countries. The incidence of rheumatism among Great Ormond Street Hospital inpatients peaked in October, preceding chorea by approximately two months. This is consistent with the current knowledge that most of the rheumatic fever symptoms appear about 10 days after the streptococcal infection, whereas Sydenham's chorea occurs typically 2–3 months after infection.
More than 80% of choreic patients were aged between 7 and 11 years. Due to a referral bias, this age may be falsely low. Indeed, the British Medical Association reported the peak age between 11 and 15 years. In the present series, the female:male ratio was 2.7, in accordance with the general choreic population of Britain towards the end of the 1800s. In children below age 7, the female preponderance is less manifest. This was observed also by Charles West, and subsequently by Osler, who stated that "the second hemi-decade contains the greatest number of cases in males, and the third the greatest number in females". In the majority of the 20th century studies, female preponderance is evident only in children over 10 years of age. These observations suggest a role for oestrogen in Sydenham's chorea expression. Supporting this view, oral contraceptives and pregnancy can cause relapses of disease.
Ten percent of the 1,548 patients whose records were researched for the British study were subsequently admitted with a relapse of chorea. Given that relapse admissions had a negative impact on the hospital cure rate, this rate might underestimate the actual relapse incidence in the general population of patients.