Cerebral MRIs of 24 children with Sydenham’s chorea and 48 matched controls were compared at the National Institutes of Health, Bethesda, MD. The caudate, putamen, and globus pallidus in the chorea group were all significantly greater in volume, whereas the total hemispheres, prefrontal, midfrontal, or thalamus areas were not increased. 
COMMENT. A cross-reactive antibody-mediated inflammation of the basal ganglia is suggested as the pathophysiology of Sydenham’s chorea. The authors admit that volumetric MRI is of limited diagnostic value because of large variability and overlap in basal ganglia size between chorea and control subjects.
Chorea in an infant with holoprosencephaly is reported from the College of Physicians and Surgeons, New York . MRI showed small, fused frontal lobes with hypoplastic caudate nuclei. This example of chorea associated with a congenital structural anomaly and undersized basal ganglia contrasts with the inflammatory hyperplasia of the caudate in Sydenham’s chorea.