Rheumatic chorea was first described by Thomas Sydenham in 1684, referring to it as a minor choreic syndrome. In 1780, Stoll was the first who observed a relationship between Sydenham chorea and rheumatic fever, but Cheadle is the one that described the main symptoms of rheumatic fever syndrome: carditis, polyarthritis, chorea, subcutaneous nodules and erythema marginatum. The link between streptococcal infection and rheumatic chorea was establish in the twentieth century.
Recent studies show that Sydenham chorea may be associated with certain neuropsychiatric disorders such as obsessive compulsive disorder, attention deficit-hyperactivity disorder (ADHD),anxiety and depression.
Sydenham chorea is the most common cause of acute acquired chorea in young people and is associated with group A beta hemolytic streptococcal infection, the causative agent of rheumatic fever. The incidence of rheumatic fever is 0,5-2 cases per 100,000 inhabitants, but Sydenham chorea represents the main manifestation of acute rheumatic fever in approximately 20% of cases. Rheumatic chorea is more common in females, female/male ratio being 2 to 1.
Sydenham Chorea Causes
Sydenham chorea is a result of an immunological cross-reaction, in which immunoglobin G antibodies produced as a response to antigens in the membrane of group A streptococci, cross-react to antigens (tubulin and lysoganglioside) in the neuronal cytoplasm of the caudate and subthalamic nuclei, due to an immunological similarity between streptococcal and neuronal antigens. In the support of this mechanism were also highlighted high levels of antineuronal antibodies in the cerebrospinal fluid and in the serum of patients with Sydenham chorea.
Sydenham Chorea Symptoms
The disease occurs predominantly in children aged between 5 and 15 years, with a slight predominance in females. Onset may be acute, symptoms develop within a few days or subacute with a progressive appearance of symptoms, over several weeks. At first patients can be very nervous, anxious and have difficulties in writing, drawing and other manual activities, unsteady gait and grimacing.
Choreic movements amplify as the disease evolve, are short, disordered, quick, sudden and polymorphic, localized in the hand and feet fingers and in evolution will interfere with breath and speech. Children begin to drop objects from hand, writing deforms and becomes illegible.
Sudden alterations in rhythm and amplitude of breathing may occur and interfere with the normal rhythm of speech. Speech becomes explosive, uncomprehensive, not only due to respiratory dysrhythmia, but also to involuntary muscle contractions of the tongue, lips, neck and facial muscles. A variable intensity of muscle weakness may be present, leading to inability to sustain a contraction. In clinical forms with predominance of hypotonia (mild chorea) hyperkinesia is attenuated. Singns of muscle weakness and hypotonia are represented by choreic hand (the arms are extended, the wrist will flex and the metacarpophalangeal joints overextend) and by the pronator sign (hyperpronation of the hands, causing the palms to face outward when the arms are held over the head). In most cases choric movements are limited to one side of the body (hemichorea).
It was also describes a form of Sydenham chorea which affects pregnant women, in the first and second trimester of pregnancy and occurs mainly in women who had at least one episode of Sydenham chorea in childhood.
Usually, the disease resolves spontaneously in 3 to 6 months and rarely lasts longer than 1 year. In a small percentage of cases, a mild choric syndrome, without functional disability, may appear after 10 years from the initial attack of Sydenham chorea. Disease recurrences are rare, about 20% of patients may experience 2 to10 recurrences, usually within the first 2 years after the initial attack.
Sydenham Chorea Diagnosis
Sydenham chorea diagnosis may be difficult because, until now no specific test is available. Disease usually develops after 1 to 6 months from a preceding streptococcal infection, but patient may not present a history of rheumatic fever and a preceding streptococcal infection cannot always be documented, due to the fact that infections can have a subclinical evolution. In 25% of Sydenham chorea cases, serologic markers of streptococcal infection can not be highlighted.
In classical cases of rheumatic fever in which chorea is the main symptom may be highlighted cardiac or joint impairments and modified laboratory tests (increased ESR, increased C-reactive protein, increased ASO titer).
Sydenham Chorea Treatment
Due to the fact that Sydenham chorea is a self-limited disease, treatment should be administrated to particular cases with severe evolution.
Anticonvulsant medications (valproic acid and carbamazepine) have proven effective in reducing choreic movements. Other drugs such as dopamine blockers (haloperidol, pimozide and clozapine) are also useful in the treatment of rheumatic chorea, especially in older children. Tetrabenazine and reserpine, as depletion dopamine agents are useful in choreic movements control, but present adverse effects such as dizziness, akathisia and dyskinesia.
Corticosteroid therapy was also used for a long time to treat rheumatic chorea, but no studies have been done in order to confirm its effectiveness.
Immunological therapy (intravenous immunoglobulin and plasmapheresis) is useful in the treatment of Sydenham chorea, but presents important side effects and is very expensive.
Another important aspect of treatment is antibiotherapy against streptococcal infection. Penicillin is administrated, amoxicillin for children. If the patient is allergic to penicillin, erythromycin or second generation cephalosporins are recommended. Children with Sydenham chorea require prophylaxis against streptococcal infections until 18 years of age.