Pediatric Movement Disorders - Chorea and Choreoathetosis

Workup

If the chorea is a new or acute symptom, it may be helpful to determine whether there has been a prior streptococcal infection (such as "strep throat"). It is known that Sydenham's chorea often follows such an infection. The importance of determining this is due to the fact that untreated streptococcal infections may lead to rheumatic fever. Up to 63% of children with Sydenham's chorea develop heart abnormalities. Sore throats and flu symptoms are very common and laboratory testing for streptococcus is not always reliable. Therefore, it may be difficult to determine if a previous streptococcal infection is the exact cause of a child's symptoms.

Laboratory tests may include a throat culture and streptococcal blood antigen test (ASLO), electrolytes (i.e., sodium, potassium, chloride, bicarbonate), magnesium, calcium, amino and organic acid studies, thyroid function, glucose, ammonia, antinuclear antigen (ANA), antiphospholipid antibodies (APLA), and a complete blood count (CBC). An additional test may be performed for the presence of acanthocytes.

In some cases, an MRI of the head may be important in order to look for structural abnormalities, such as those related to a tumor, stroke, metabolic or degenerative disorders, or a previous injury due to low oxygen.