Chorea: whither comest it?

Chorea-the term itself is a rather peculiar one. The word chorea is derived from the Greek word for dance and originally was applied to describe the dancelike gait of the dancing mania, a hysterical disorder of the late Middle Ages. The term is now used to describe an entire class of abnormal spontaneous movements. Each of these movements is a single, isolated muscle action: a short, rapid , uncoordinated jerk. These jerks can be proximal or distal and are of sufficient magnitude to move the involved limb. The simultaneous or successive occurrence of two or more such isolated movements can result in complex patterns of movement, and the superimposition of these movements on normal movements can cause a dancelike gait. What little we know and understand about chorea is based on our knowledge of a single disease state: Huntington chorea. In Huntington chorea, the major pathologic features are limited to the corpus striatum and cerebral cortex. Striatal atrophy is the most striking change. Although particular involvement of the small neurons of the caudate nucleus is present, it is not unusual to see degeneration of the large caudate neurons as well. Associated with this marked neuronal loss is extensive proliferation of astrocytes. The other striking pathologic feature is diffuse cerebral atrophy. This takes the form of a general reduction in the population of cortical cells, with particularly heavy cell loss in layers 3, 5, and 6. It generally is accepted that the choreiform movements of Huntington disease are related to striatal pathologic changes and that the mental changes are related to cortical pathologic changes. Thomas Sydenham first described acute chorea in 1685. Today the term Sydenham chorea is applied to instances of sporadic chorea that occur during childhood and adolescence. Over the years, it has come to be accepted that in most instances, this syndrome is of rheumatic origin . It is thought