Diagnosis and Treatment of Sydenham's Chorea

Sydenham's Chorea, also known as St. Vitus' Dance, is a neurological movement disorder which occurs in up to 20% of patients with Acute Rheumatic Fever and is characterized by rapid and uncontrolled jerking movements of the face, neck, trunk, and limbs. It can remain latent for up to six months and occurs most often in children between the ages of five and fifteen. Chorea is more common in females than in males and can last from two months to two years. Those who have had Sydenham's Chorea are at risk of recurrence.

Choreatic movements may appear suddenly or they may begin gradually and worsen over the course of a few weeks. In addition to muscle control, Sydenham's Chorea also affects speech and basic skills such as walking and going to the bathroom. Facial grimacing, drooling, and clenched fists sometimes occur in severe cases. Other symptoms include muscle weakness, diminished muscle tone, and emotional disturbances, particularly obsessive-compulsive disorder.

Risk Factors

While the underlying mechanisms are unknown, the main cause of Sydenham's Chorea is believed to be Acute Rheumatic Fever. ARF occurs in response to a streptococcal bacterial infection and can cause permanent damage to the heart. Some experts believe that certain antibodies created in response to the streptococcal bacteria may react against some regions of the brain. In this theory, known as autoimmune mimicry, the bacterial protein is believed to be similar to the body's own protein and the immune system may be unable to distinguish between them. Genetics are believed to increase this risk. Other common factors are malnutrition and overcrowded living conditions. Because Sydenham's Chorea occurs most often in pubescent girls, estrogen is also believed to be a contributing factor.

Diagnosis

Because Sydenham's Chorea may not appear for up to six months after the initial streptococcal infection, diagnosis is entirely clinical. Symptoms must be identified through careful patient history and other movement disorders such as Cerebral Palsy and Huntington's Chorea must be ruled out.

In some cases, an MRI is performed. Patients with Sydenham's Chorea often have abnormal EEG results. These results frequently show slow brain wave patterns and an enlargement of certain areas of the brain such as the basal ganglia, which is associated with motor and learning functions.

A cardiac evaluation should also be performed in order to detect altered blood flow, damaged heart valves, and cardiac murmurs which can be caused by ARF. An enlargement of the heart may also be detected.

Treatment

Antibiotics are given to treat the ARF and any remaining streptococcal bacteria. The antibiotics are sometimes given on an ongoing and indefinite basis to prevent reinfection. In mild cases, Sydenham's Chorea is not treated with any drugs. No pharmaceuticals have been found to be consistently effective and the chorea usually disappears on its own after a few weeks. When the movements are severe, antipsychotic drugs such as risperidone or haloperidol are prescribed to calm the patient and moderate the movements. Anti-inflammatory drugs may be prescribed for heart inflammation. Patients, particularly those with heart damage, should remain watchful for recurrences, but once the movements are controlled and the chorea begins to resolve, regular activity may be resumed.