Chorea: non-genetic causes

The aim of this article is to review the literature on the non-genetic causes of chorea. The differential diagnosis of the large number of causes of sporadic chorea is often a challenging task. Interest has also been growing in the possibility that the mechanism responsible for Sydenham's chorea plays a role in the pathogeneis of other neuropsychiatric disorders.

Stroke is the main cause of sporadic chorea. Sydenham's chorea shares clinical features with tic disorders, such as obsessive-compulsive disorder and attention deficit hyperactivity disorder. However, there are unequivocal differences between Sydenham's chorea and Tourette's syndrome. There is initial evidence suggesting the beneficial effect of immunosuppression in Sydenham's chorea. Other autoimmune causes of chorea include systemic lupus erythematosus as well as paraneoplastic syndromes. The growing list of drugs associated with chorea include lamotrigine, methadone and lithium. Among infectious agents, HIV is the leading reported cause of chorea.

Patients with sporadic chorea require a thorough work up because numerous causes can lead to this condition. It remains unconfirmed whether the pathogenic mechanisms of Sydenham's chorea are responsible for other conditions such as isolated obsessive-compulsive disorder or Tourette's syndrome. Drugs and infectious agents, especially HIV, are often implicated in the causes of chorea.